Emissions fail - high hydrocarbons in exhaust

[DaraSue]

So my car failed emissions, where AFAIK it passed with flying colors the last two times. It read 200PPM (hydrocarbons) on the 2500 RPM check, 175 on the idle check.

Things we've already tried: Checking the dwell & adjusting the mixture, making sure the O2 sensor wasn't loose, checking for vacuum leaks

Things we're going to try: replacing the spark plug wires

Is there anything else obvious that I'm missing? I feel like I must have screwed something up when I was working on it last fall. I did trip over the mixture unit while it was sitting on the floor, is it possible that I broke something inside it?

The engine was overhauled in winter 2016 at DMCCA and it has a DPI exhaust (new when I bought the car in summer 2016.

[David T]

If the fuel is older than a couple of months use it all up or remove it and get fresh stuff in. Try a can of Techron to clean the injectors. A bad spray pattern can mess up the emissions. Is the frequency valve buzzing?

[DaraSue]

If the fuel is older than a couple of months use it all up or remove it and get fresh stuff in. Try a can of Techron to clean the injectors. A bad spray pattern can mess up the emissions. Is the frequency valve buzzing?

The gas isn't more than a month old and I almost always put Chevron with Techron in it. Not sure about the valve, it should buzz with the mixture is set correctly, is that right?

[David T]

The valve is supposed to buzz whenever the motor is running.

[NckT]

Disconnect the oxygen sensor electrical connection first and see if it buzzes. If it does when the engine is cold but stops when the engine is warm, then the duty cycle may have gone full swing such that the valve is fully open or fully closed.

I'll assume you've not replaced the lambda relay lately, as this needs a double contact single throw type.

Does the DPI "performance" exhaust have catalytic converters in?

Have you done fuel pressures tests?

[bytes311]

I just smogged my car 2 days ago and it failed with higher than normal HC. There were no vacuum leaks, and the dwell was properly set and the FV buzzed loud and continuous. The problem turned out to be a bad or faulty O2 sensor (it was only 3 years old, from DMCH). The shop put in a new Bosch sensor and re-adjusted the duty cycle. The HC was literally cut in half and passed. My car feels like it has so much more power now, too.

[David T]

A sensor can get contaminated easily. One tankful of gas with any amount of lead in it can do it. Using silicone sealer that is not "sensor safe" can do it too. I asked if the FV was buzzing so that would indicate that the Lambda system was functioning and the duty cycle was at least close if he hears it. A place to start and you don't need any tools to check.

[DaraSue]

The car's at the shop so I'll have to go by and check out the frequency valve on Mon.

The exhaust IIRC is dual-cat, but was installed by the guy who sold me the car, not actually done at DPI. He said he put a new O2 sensor in, not sure if it came with the exhaust kit or was purchased elsewhere. Are these sensors specific to the car or can they be bought off the shelf?

I did have an issue where the O2 sensor was coming loose last year. Could something have gotten into it or gotten damaged? Although the last time it happened (that I noticed) was around May and it had passed smog since then. It didn't have any sealer on that I noticed.

I generally only buy name-brand, top-tier certified gas, so it shouldn't have had any lead in it, should it? I didn't think you could even get leaded gas in the US anymore (except from airport fuel trucks). The worst gas I remember buying in the last year or so was Shell and Valero. I can't swear with 100% certainty that I never put generic in if I was out in the middle of nowhere and running low but if I did that would have been on my cross-country trip last May (before last year's smog inspection). I always get 91+, too.

[Chris 16409]

You still need to smog your car!!!!! I thought only us Californians were subject to totalitarian smog laws! Being at DCS this month, everybody from the Midwest was shocked that DeLoreans were still emissions tested.

[AugustneverEnds]

You still need to smog your car!!!!! I thought only us Californians were subject to totalitarian smog laws! Being at DCS this month, everybody from the Midwest was shocked that DeLoreans were still emissions tested.

Even the People's Republic of NY exempts cars 25yrs and older from emissions tests. At least where I am not sure about NYC.

I'd definitely start with the oxygen sensor. If it is NOS it may have been installed recently but it's still 36 or more years old.

[DaraSue]

Technically I could register it as "vintage" and not have to smog it but officially you're not supposed to daily-drive it. I'd rather have it running correctly because I still want to drive it a lot and after all the cash I've dropped on it, I feel like it should be perfect. :banghead: (Also I'd have to give up my vanity plates if I did that and get one with only 5 letters.)

[NckT]

Disconnect the oxygen sensor electrical connection first and see if it buzzes. If it does when the engine is cold but stops when the engine is warm, then the duty cycle may have gone full swing such that the valve is fully open or fully closed.

I'll assume you've not replaced the lambda relay lately, as this needs a double contact single throw type.

Does the DPI "performance" exhaust have catalytic converters in?

Have you done fuel pressures tests?

Done any of the above yet?

Disconnecting the electrical connection from the oxygen sensor defaults the fuel computer to operating the frequency (bleed off) valve to 50% duty cycle ie it buzzes. This is when the car is at operating temperature.
The reason I asked if it buzzes when cold is that the lambda switch should default the duty cycle to 60% and you should hear it buzz.
If it buzzes when cold but not when hot then as described above it goes full swing one way.

If you don't hear it buzz at all with the oxygen sensor disconnected then it'll be an electrical issue. This is usually brought on by someone replacing the relaid in the relay compartment without taking note that the lambda relay is a particular type described in the previous post hence the question.
In a small number of cases with a good oxygen sensor confirmed looking at the trace with an oscilloscope and frequency valve not buzzing due to swing of the duty cycle and fuel mixture is correct with oxygen sensor disconnected, then the quad op amp in the fuel ecu has gone bad and needs replacing.

[DaraSue]

I didn't have time to do much with it today except verify that the FV was buzzing. I'll go over there tomorrow and try disconnecting the sensor to see what happens.

The seller replaced the relay box before I got it and I think everything was legit but I'll double-check that it's the right one.

Haven't done a fuel pressure check yet that I know of. I'll see if they can try that tomorrow. Would I notice other symptoms if that were the issue? Seems to be running pretty normally.

[Rich]

Some answers to earlier questions are inserted below. And an easy check before you go to the trouble of checking the fuel system.

Assuming the business end of the O2 sensor is OK you might also be sure that the black wire to the sensor isn't grounding out anywhere, that no varmints have chewed it apart and that the other end of it is well-connected to the Lambda computer.


The car's at the shop so I'll have to go by and check out the frequency valve on Mon.

The exhaust IIRC is dual-cat, but was installed by the guy who sold me the car, not actually done at DPI. He said he put a new O2 sensor in, not sure if it came with the exhaust kit or was purchased elsewhere. Are these sensors specific to the car or can they be bought off the shelf? They are not D-specific - they were used on lots of cars of our vintage and are still widely available.

I did have an issue where the O2 sensor was coming loose last year. Could something have gotten into it or gotten damaged? Unlikely that the sensor is bad at the business end since it smogged OK after your fix and it had no sealer on it and it's so new. Although the last time it happened (that I noticed) was around May and it had passed smog since then. It didn't have any sealer on that I noticed.

I generally only buy name-brand, top-tier certified gas, so it shouldn't have had any lead in it, should it? Aviation gas still has lead in it, I think. No gas stations sell leaded that I know of.

[DaraSue]

Is the o2 sensor supposed to just unplug somewhere? Mine looks like it's been soldered & heatshrunk on the sensor end.

Also does this look right?

57919

[DaraSue]

Just noticed the top two bolts are off the airbox. I thought they took them off here but the mechanic says they didn't. The bix is pretty loose, would that be enough to screw up the test results?

[David T]

No. Make sure there is a plug in the hole over the mixture screw though.

[dn010]

Is the o2 sensor supposed to just unplug somewhere? Mine looks like it's been soldered & heatshrunk on the sensor end.

Also does this look right?

57919

Follow the 02 wire from the sensor back. The wire is long. It should have a large rubber connector down the line that connects it to the larger blue wire. The connector should be going into the car through the fiberglass behind/above the rear driver side tire, on the outside of where all the blue wires are that you have pictured.

I don't see anything alarming in the photo other than the rubber grommet pushed back from the fiberglass, push it back and into the fiberglass to seal up the hole that is there without it.

[DaraSue]

I couldn't even find the other end of it but one of the mechanics said that where it went into the bulkhead there was a lot of leftover wire knotted up, is that normal?

[dn010]

The 02 sensor wire is pretty long, I wouldn't be surprised if someone tied the excess up. Here is a photo of the wire, courtesy of DAP. It is the only photo I could find quickly for you. When installed correctly, the blue wire is pushed all the way into and sealed into the fiberglass with the rubber piece you see extending.

https://www.deloreanautoparts.com/delorean-parts/images/Lambda-connection.jpg

[DaraSue]

I think I found mine. Is this part supposed to unplug?57920

[dn010]

That is it. Pull on it from the end and it should pull out like seen in the photo I posted. You can then disconnect it. It may also just unplug as you pull on it without the whole connector and blue wire coming out. Either way is good.

[DaraSue]

So my blue wire comes out the bulkhead and goes into this thing, what is it?

57921

[dn010]

Silver box is the “lambda” ECU. Black box with two plugs is the idle ECU.

[DaraSue]

I'm trying the test with the sensor unplugged, seems like it idles a little choppy but the valve is buzzing. How hot does it need to get? Up to the unmarked white line?


https://youtu.be/YElPUoXoAjU

[DaraSue]

https://youtu.be/YElPUoXoAjU

[DaraSue]

It got up to the 220 line and I never heard it stop buzzing but now I've got another problem. My cooling fans didn't come on. :banghead::banghead::banghead:

NOW what?

(Just tried it again and they still don't come on. When I put the a/c on they finally did. Is it the otterstadt? Thr coolant lines by the radiator are stone cold.)

[hippieman9]

It got up to the 220 line and I never heard it stop buzzing but now I've got another problem. My cooling fans didn't come on. :banghead::banghead::banghead:

NOW what?

(Just tried it again and they still don't come on. When I put the a/c on they finally did. Is it the otterstadt? Thr coolant lines by the radiator are stone cold.)

Sounds like the thermostat is not opening. are the hoses in the engine bay getting hot? also is your Otterstat pointing to the ground?

[hippieman9]

https://youtu.be/YElPUoXoAjU

Is it running with out the O2 sensor in the pipe? sounds like it. that would be an exhaust leak.

[DaraSue]

The sensor was in the pipe but the connector was unplugged. I was trying to do the test Nick suggested to see if the frequency valve buzzed when the engine was hot and rule out an electrical issue.

Engine bay hoses were hot, otterstadt is pointed down & connections seemed ok.

[hippieman9]

The sensor was in the pipe but the connector was unplugged. I was trying to do the test Nick suggested to see if the frequency valve buzzed when the engine was hot and rule out an electrical issue.

Engine bay hoses were hot, otterstadt is pointed down & connections seemed ok.

Ok, To test the fans 1. jump the Otterstat wires and the fans should kick on, or 2. set the mode switch to A/C then turn the ignition switch to the run position and listen for the fans to kick on.

Do you have Daves Fan relays??

[DaraSue]

Ok, To test the fans 1. jump the Otterstat wires and the fans should kick on, or 2. set the mode switch to A/C then turn the ignition switch to the run position and listen for the fans to kick on.

Do you have Daves Fan relays??

They come on if I turn the a/c on. I don't think it's Dave's relay but it's a fused one.

[Ron]

I always get 91+, too.
If your engine is stock, it should be running 87.
The capacities chart in the Owner's Manual says "91 octane", but on the next page says:

Fuel Requirements
U.S.A.
Your De Lorean is designed to operate at
factory specifications at UNLEADED
GASOLINE only of at least 87 anti-knock
index (R+M/2) (91 research octane number).



In the US, 91 (R+M/2) is not the same as 91 (RON). Our 91 is mainly for high compression engines. It's harder to ignite and burns longer. What does not burn can collect in the combustion chamber or flow out with the exhaust, raising emissions. This or setting it up with 87, as it should be, then changing to 91 can contribute to/cause a failed smog test. However, many report using 91 w/o problems and even passing the tests...
It's probably not THE problem, but it sure does't help!

91 is a waste of money and not what the D's system is designed for/expects...

fwiw:
Go on a cool/humid day.
If you use cleaning additives, run it until the tank is nearly empty, then run at least a tank full of fuel only through it before your appointment.

[David T]

In my experience the engine runs just fine on 87. Using higher octane seems to improve the mileage slightly and if you are borderline on passing it can help with the emissions BUT. For the difference in price it isn't worth it. If you have problems using 87 octane better to fix the problem than trying to avoid it by using higher octane fuel. For those with turbos, they should be using the highest octane they can get. As for lead, in most States you can't get gasoline with lead anymore. Aviation fuel still contains lead but not as much as it used to. It's called 100LL and it is EXPENSIVE! Then there is racing gas. Meant for off -road use only so if you get caught with it in your car there could be severe fines. Bottom line, if you are stock you can and should use 87.

[hippieman9]

They come on if I turn the a/c on. I don't think it's Dave's relay but it's a fused one.

Fused jumper wire?

[DaraSue]

Fused jumper wire?

No, AFAIK it's a legit relay, it has the yellow wires with the fuses in them. I think it's this one? http://store.delorean.com/p-10219-relay-update-kit.aspx

The seller said he installed an updated relay kit so it was probably that same one.

[hippieman9]

No, AFAIK it's a legit relay, it has the yellow wires with the fuses in them. I think it's this one? http://store.delorean.com/p-10219-relay-update-kit.aspx

The seller said he installed an updated relay kit so it was probably that same one.

Ok Thats the Jumper wire with fuses. Check out Daves relays, They are awesome. Theres a fan fail that if one of the fuses blow, the fan fail light will come on on the dash. With the jumper wire like you have, the fuse can blow and you will never know you have a problem.
Dave also has a Fan relay that starts the fans one at a time (this is the relay next to the jumper wire) eliminates the big load on the charging system when the fans kick on. it also keeps the fans running longer so they don't cycle with the A/C compressor I highly recommend these and his RPM relay. https://dm-eng.weebly.com/

[NckT]

I think I found mine. Is this part supposed to unplug?57920

Yes

[Ron]

The sensor was in the pipe but the connector was unplugged. I was trying to do the test Nick suggested to see if the frequency valve buzzed when the engine was hot and rule out an electrical issue.

Engine bay hoses were hot, otterstadt is pointed down & connections seemed ok.

Probably a good idea to resolve this first... You can turn the key on then jump the Otterstat wires in place, or plug them together, in case you didn't know.

[DaraSue]

Probably a good idea to resolve this first... You can turn the key on then jump the Otterstat wires in place, or plug them together, in case you didn't know.

Yeah, I called the mechanic today and told him to do it but if he hasn't by tomorrow I'll go over there and try it myself.

[DaraSue]

Went to the shop just now and tested the otterstat, fans came on with the wire jumped so hopefully that's one problem solved. Not sure when it went bad, though. It was fine on my road trip in June. I assume it's been working since then but I don't sit in traffic much to notice.

Really hoping it wasn't out while they were idling the car for the emissions test. Would overheating account for these results?:nervous:

[Rich]

....Really hoping it wasn't out while they were idling the car for the emissions test. Would overheating account for these results?:nervous:

I can't answer that question for sure except to say that high coolant/engine temp. isn't listed among these (LINK) 6 causes of high HC emissions readings (https://www.smogtips.com/failed-high-hydrocarbons-HC.cfm).

In reviewing that list:
- #1 is unlikely unless somebody fiddled with the timing since it passed the last smog test
- #5 doesn't apply - these cars don't have an air injection system

That leaves 4 others on the list, in no particular order - bad cat, poor ignition, lean fuel/air ratio, and (uggghhh) low compression.

The links on that webpage show some causes of high CO and high NOx if you go there. If you got either of those tested then depending on pass/fail for each of them maybe those links tell you something useful regarding causes that are also on the high-HC link.

[NckT]

I'm trying the test with the sensor unplugged, seems like it idles a little choppy but the valve is buzzing. How hot does it need to get? Up to the unmarked white line?


https://youtu.be/YElPUoXoAjU

Does the frequency valve still buzz with the sensor plugged in and the engine warm? (Temp gauge between the 2 white lines)

[DaraSue]

We replaced the otterstat today (the mechanic did most of the work while I held the flashlight). The old one didn't want to come out and the new one leaked bad enough that he ended up putting permatex around the edge where the seal goes. Has this happened to anybody else?

Had to wait for the sealant to set so I didn't get to do much else with it. The old one had a fair amount of reddish crud on it which might have been why it wasn't working as expected. Hoping that was just leftover from my previous block rot woes and not a sign that the creeping crud is back. :nervous:

[opethmike]

Have you hugged the car? DeLoreans are quite needy and respond well to hugs.

[DaraSue]

Have you hugged the car? DeLoreans are quite needy and respond well to hugs.

At this point I'd cheerfully make out with it, if it would get it back on the road any faster... :tongue_stick:

[hippieman9]

We replaced the otterstat today (the mechanic did most of the work while I held the flashlight). The old one didn't want to come out and the new one leaked bad enough that he ended up putting permatex around the edge where the seal goes. Has this happened to anybody else?

Had to wait for the sealant to set so I didn't get to do much else with it. The old one had a fair amount of reddish crud on it which might have been why it wasn't working as expected. Hoping that was just leftover from my previous block rot woes and not a sign that the creeping crud is back. :nervous:

Never had that issue, It is a pretty tight fit though. I see Delorean Go sells a thread in version of the otter stat and pipe. pretty interesting way to go if you continue t have issues. Sounds like you may have corrosion where the otterstat seats.

Make a mental note that when you drain the coolant next time, to remove that pipe and clean it up good to smooth out the Otterstat seating area. Just my .02

[DaraSue]

I didn't have time to go visit it today but the mechanic tells me he finally got the leak to stop and the fans are coming in as they should be. So now we're back to the original problem. He's supposed to change the O2 sensor tomorrow and retest it.

[hippieman9]

I didn't have time to go visit it today but the mechanic tells me he finally got the leak to stop and the fans are coming in as they should be. So now we're back to the original problem. He's supposed to change the O2 sensor tomorrow and retest it.

thats good, its a step in the right direction!

[DaraSue]

I went by the shop today to check the FV with the o2 sensor connected. It buzzed all the way up to 220, at which point I shut it off b/c the fans still weren't coming on. :banghead::banghead::banghead: So did I just waste a week and trash a perfectly good otterstat for nothing? What else could be causing this?

[DaraSue]

Also I'm not sure it's running that different with the sensor plugged in, is that a confirmation that it's bad?


https://youtu.be/bKgCeuW1VZE

[DaraSue]

https://youtu.be/bKgCeuW1VZE

[DMC-Ron]

I went by the shop today to check the FV with the o2 sensor connected. It buzzed all the way up to 220, at which point I shut it off b/c the fans still weren't coming on. :banghead::banghead::banghead: So did I just waste a week and trash a perfectly good otterstat for nothing? What else could be causing this?

If you are not getting any fans, even with the AC turned on, then possible suspects are (1)cooling fan relay, (2)the fan fail relay (usually has two fused jumpers), or (3)the cooling fan thermal trip.

1. The cooling fan relay might be the most likely problem. You may have Dave's electronic version or just a regular mechanical relay. If you make a jumper with some wire and a a couple of male spade connectors you can remove the relay and install the jumper. This will bypass the cooling fan relay to see if it is the issue. If the jumper gets your fans working then it may be (A) bad relay, or (B) the circuit that pulls in the relay. A) It's fairly easy to bench test the relay. B) most likely suspect is a diode between the otterstat and the fan cooling relay that may have gone bad and is not letting the otterstat pull in the cooling relay.

2. A fused jumper can also be placed across the thermal trip (or just take a DC volt meter reading. ~12 volt reading would mean it is open and not resetting.

3. Inspect the fan fail relay socket. This should be jumpered with two inline fuses (or you may have Dave's electronic fan fail relay). Check the connection and the fuses. The single connector with two wires stuffed in it is prone to heat and may have failed. If you have Dave's relay, they're pretty robust and not known for failures, but you could remove it and put in a temporary fused jumper (with one fuse jumper you would check one fan at a time).

If you are getting cooling fans with the AC on then disregard all this and take another look at the otterstat to make sure it was installed correctly and the diode mentioned above. With the car hot, you could check continuity of the otterstat and verify it's contacts are closing.

Ron

[DaraSue]

The fans do come on if I turn the a/c on or jump the otterstat wires. Or at least they did prior to changing the otterstat out last week. I called Mike @ MW about it and he said sometimes the fans take longer to come on in a stationary idle from a cold start - sometimes til it's between the 220 line and the red line. Has this been anyone else's experience? I'm not sure I've ever actually idle-checked mine like this before, usually they come on just below the 220 line but that's when I'm stopped after driving.

If the FV buzzes even when warm does that mean it's working correctly?

[Bitsyncmaster]

The fans do come on if I turn the a/c on or jump the otterstat wires. Or at least they did prior to changing the otterstat out last week. I called Mike @ MW about it and he said sometimes the fans take longer to come on in a stationary idle from a cold start - sometimes til it's between the 220 line and the red line. Has this been anyone else's experience? I'm not sure I've ever actually idle-checked mine like this before, usually they come on just below the 220 line but that's when I'm stopped after driving.

If the FV buzzes even when warm does that mean it's working correctly?

A lot of cars the fans turn on around the 1/4 mark and some cars don't turn on till the 220 mark. Don't know why that difference. But the fans should turn on after the thermostat opens and the engine heats up some more. What you can do is feel the coolant hose on the drivers side of the engine and note what your temp gauge reads. Then note where the gauge reads when the fans turn on. I would not think the gauge should go much more than 1/8 movement higher. Some vendors sell an otterstat that turns the fans on at a lower temp than the stock otterstat did.

The FV should always buzz but you still need to check the mixture with a dwell meter.

[David T]

The point at which the fans come on varies because of the setting of the O switch and the accuracy of the temp gauge. Get an infra red thermometer and check the temp if you have concerns. Typically HC is high if the engine is not at operating temp (below 180). I don't think your high HC is due to the fans but getting the fans running right is so important to preventing overheating that you MUST get that fixed ASAP. Then you can concentrate on getting your HC lower.

[Ron]

...getting the fans running right is so important to preventing overheating that you MUST get that fixed ASAP. Then you can concentrate on getting your HC lower.
+1

[Rich]

...I don't think your high HC is due to the fans but getting the fans running right is so important to preventing overheating that you MUST get that fixed ASAP. Then you can concentrate on getting your HC lower.

+1 also.

And along the lines of getting the cooling system sorted:

1. Are you positive the system is fully bled, including the radiator? I haven't checked the previous posts to see about this.

I recently assisted on a D suffering from a high-gauge-temp-before-fans-switch-on-during-long-idle problem. Like you, the owner knew to keep an eye on the gauge and was concerned about the fans not coming on soon enough during long idles.

A verified rad bleed - with no other intervention - solved that problem on that car.

[DaraSue]

I called the shop this morning to remind him to keep an eye on it if he idled it and he said he'd already retested it on Fri and it passed. He sent me the printout and it was back to where it should have been. He never did change the O2 sensor so idek what that was all about? Unless he happened to take it in fairly soon after I idle-checked it and it was warmer than it had been previously.

I'm going to pick it up tomorrow and I'll see how the temp behaves on the way home.

[Rich]

I called the shop this morning.... and he said he'd already retested it on Fri and it passed.

Very nice to get this happy-ending report!

You may never know why it failed previous tests.

And the coolant temp will probably be fine on your way home from the shop. Unless you idle it for a real long time again.

[DaraSue]

Drove it home today (surface roads, about 8 miles), temp stayed normal (around the unmarked white line) but I had the A/C on the whole way. When I let it idle after arriving at home, it got up to just about the 220 line without the fans coming on, at which point I gave up and shut it off.

Next week I'll try bleeding it and see if that helps. Ryan F (hippieman9 on here) sent me some instructions so hopefully I'll make less of a mess of it than I did last time.

[opethmike]

One thing I do when bleeding the coolant on rear & mid-engine cars is that I back the rear wheels up on ramps, and then let the car sit overnight. The hope is that with the rear higher than normal that the air pockets will be encouraged to collect at the bleeder screw.

[David T]

No need to raise the rear of the car. Just buy or rent a coolant system pressure tester. Pump it up and let the air out at the bleeder over the thermostat and loosen the small hose on the top, right side of the radiator til you get all of the air out. When you finish you should wind up with the header tank 1/2 full cold. Any air still in the system will work it's way out unless you have leaks.

[DaraSue]

Already got a pressure tester (bought it on my way home when I first got the car). With the tester I don't need to have the car running to bleed it?

I've driven to and from work a few times, twice during the day with the A/C on (outside temp 80-90F), once in the morning with A/C off (temp 65-70F), once late pm with A/C off (temp 90-95F)* and twice at night, once with the heater on, once with it off, both times probably 60-70F. Temperature was normal, hovering around the unmarked line, every time. If there's something wrong with my system, I think maybe it could have been that way for months and I just never had occasion to notice until I idled it for prolonged periods?

*I had a 30+ mph headwind for this one though, so that may have skewed the results.

[David T]

The motor does not run while you bleed the cooling system with a pressure tester. Don't pump over 15 psi, 10 is all you really need. Before you start, the header tank should be slightly more than 1/2 full and when you finish you should have to add a little to get it back to 1/2 full cold. if you find you have a hard time getting all of the air out, make sure the thermostat has a "jiggle pin" so air can bypass it when it is closed. If it doesn't, drill a 1/16" hole in it.

[Rich]

Already got a pressure tester (bought it on my way home when I first got the car). With the tester I don't need to have the car running to bleed it?

I've driven to and from work a few times, twice during the day with the A/C on (outside temp 80-90F), once in the morning with A/C off (temp 65-70F), once late pm with A/C off (temp 90-95F)* and twice at night, once with the heater on, once with it off, both times probably 60-70F. Temperature was normal, hovering around the unmarked line, every time. If there's something wrong with my system, I think maybe it could have been that way for months and I just never had occasion to notice until I idled it for prolonged periods?

It's more than likely the system could have had some air in the radiator and/or the engine all this time.

Sounds like you have the components sorted out. Since you do not know the system is bled then assume it isn't.

Bleeding the cooling system is one of the easiest and most important jobs DeLorean. It needs to be done - and done right, which means doing it at both ends of the car - every time coolant is drained/changed. New owners or owners who are not sure if there's air in the system should check/bleed it to be sure.

As David T. notes, if there was air in the system then the coolant level will drop in the header tank after the bleeding is done. That's one way you will know it needed to be bled. And if your fans-won't-start-at-expected-gauge-temp-during-long-idle problem goes away after you fully bleed it that's another way you will know.

[DaraSue]

Well, I tried the pressure tester method of bleeding and it did bleed a fair amount of air, but the fans still aren't coming on. I let it get one or two needle-widths above the 220 line this time, and nothing. This was after driving about 8 miles on surface roads in rush hour traffic. It had crept up close to the 220 line during the drive but then dropped back down to about midwaybetween the 220 and the unmarked white line, but I didn't actually hear the fans come on so it may have just been because we got moving at a decent speed again.

The mechanic said he bled it too after verifying that the otterstat seal was holding and they came on around 212-225. He said he checked the temp at the pipe by the otterstat and he thought my gauge read about 15 low, but when I used my own thermometer it looked like it was pretty accurate (although mine's from Wal-Mart so maybe it isn't the greatest). Arrrgh. I guess I need to try bleeding it with the engine running next?

[Rich]

Well, I tried the pressure tester method of bleeding and it did bleed a fair amount of air, but the fans still aren't coming on...... Arrrgh. I guess I need to try bleeding it with the engine running next?

More info would be good to have.

From where did it bleed a fair amount of air? Upper right rad hose (the small hose/nipple?) or the bleeder screw on the pump housing?

Getting air out of each of those spots is important. One of them is not enough...

Because there is a bleeder screw at the engine and not one at the radiator many people, including mechanics, only pay attention to the engine side...

Agreeing with David T. that running the engine isn't important to proper coolant bleeding. The car can be bled at rest.

And the rad can be bled without pressure. Gravity is enough for that end.

[DaraSue]

More info would be good to have.

From where did it bleed a fair amount of air? Upper right rad hose (the small hose/nipple?) or the bleeder screw on the pump housing?

Getting air out of each of those spots is important. One of them is not enough...

Because there is a bleeder screw at the engine and not one at the radiator many people, including mechanics, only pay attention to the engine side...

Agreeing with David T. that running the engine isn't important to proper coolant bleeding. The car can be bled at rest.

And the rad can be bled without pressure. Gravity is enough for that end.

I loosened the radiator hose first (the small one on the upper right where it attaches to the radiator), and that seemed to lose the most air, there were several seconds where I could hear it hissing out before it started squirting out antifreeze. I did the bleeder screw on the thermostat housing second, it seemed to bleed antifreeze fairly quickly. I had parked the car nose-down for a couple hours first, should I have tried to keep it level? My driveway slants down, my garage slants slightly up.

Also, IDK if this is relevant to my original problem, but while I was poking around in the fusebox after the last idle test, I noticed my lambda relay was really hot, like too hot to touch. Is that normal?

[opethmike]

No, you definitely want that rear end up.

[Bitsyncmaster]

Also, IDK if this is relevant to my original problem, but while I was poking around in the fusebox after the last idle test, I noticed my lambda relay was really hot, like too hot to touch. Is that normal?

Yes the lambda relay normally runs very hot. You can put in a standard relay if you rewire that center pin.

Remove the center pin with the red/purple wire.
Cut the pin off and connect that red/purple wire to the green/yellow wire on the other pin in that socket.
If you use my solid state relay, it would be the same as my blower relay.

[iflights]

Yes the lambda relay normally runs very hot. You can put in a standard relay if you rewire that center pin.

Remove the center pin with the red/purple wire.
Cut the pin off and connect that red/purple wire to the green/yellow wire on the other pin in that socket.
If you use my solid state relay, it would be the same as my blower relay.

I wasn't aware there was a solid-state replacement for the lambda relay. It is plug and play, or are these 2 wiring changes needed in addition?

[Bitsyncmaster]

I wasn't aware there was a solid-state replacement for the lambda relay. It is plug and play, or are these 2 wiring changes needed in addition?

You would need to make that wiring change to use a standard relay or my relay.

I also use my relays for replacing the AUX relays but had to put new pins on the wires since the OEM relays used larger pins.

[Rich]

I loosened the radiator hose first (the small one on the upper right where it attaches to the radiator), and that seemed to lose the most air, there were several seconds where I could hear it hissing out before it started squirting out antifreeze.

Nice that you got some air out of the front end.

This next question will sound picky but it's important to know.

You report that when you pulled the small upper hose there was hissing and then you got coolant.....from where was the coolant flowing?

From only the nipple on the radiator or from only the end of the hose? Or from both?

[DaraSue]

Nice that you got some air out of the front end.

This next question will sound picky but it's important to know.

You report that when you pulled the small upper hose there was hissing and then you got coolant.....from where was the coolant flowing?

From only the nipple on the radiator or from only the end of the hose? Or from both?

I never actually got the hose all the way off but when I jiggled it, first air came out and then coolant started squirting out and when I tried to push the hose further back on, more coolant ran out. Did I do it wrong?

[Rich]

I never actually got the hose all the way off but when I jiggled it, first air came out and then coolant started squirting out and when I tried to push the hose further back on, more coolant ran out. Did I do it wrong?

Hard to say. A first guess is you got it filled. I think you said you did it with the system pressurized. In that case there would be lots of flow but perhaps it was too exciting to see what came out of where....

When I bleed the radiator I don't pressurize the system. I do pop the pressure cap off of the header tank.

I can pop the hose off its nipple and then hold it closed with my thumb over the end after I see coolant coming out of the hose. Then I wait for the radiator purge to its air thru the nipple. As soon as I see coolant coming from the nipple I put the hose back on. Bled for sure.

It's a fast job in case you feel like trying again....you can do it cold, no pressure tester, at least not for that end of the car.

[DaraSue]

Is there a trick to getting the hose all the way off? I was having a hard time with it and was afraid of breaking something. (Not original radiator but a DMCH one.)

[David T]

You don't take the little hose off. You just loosen it enough to let the air out. it doens't matter where the air comes from, just get it out. What little may be left will eventually work it's way out. If the temp gauge indicates the motor is getting too hot, confirm with an infra red temp gauge. If it is too hot either the thermostat is not opening at the right temperature, the "O" switch is bad or you still have air in the system (or a combination of these causes).

[DMC-Ron]

Perhaps you've already checked it, but you could have a bad diode. Its not difficult to jumper the otterstat and make sure the fans come on. Hate to see you go to all the trouble of burping the coolant then find out it's an electrical issue between the otterstat and the cooling fan relay.

Ron

[DaraSue]

Fans come on with the otterstat wires jumped, or they did last time I checked. I've checked the temp with an IR thermometer and the pipe by the otterstat is getting hot enough that it should be tripping. Dave S @ MW thinks it's possible the new otterstat may have failed so I'll try replacing it again. I ordered one of the new style ones with the screw-in otterstat from DeLorean Go just in case.

[iflights]

Fans come on with the otterstat wires jumped, or they did last time I checked. I've checked the temp with an IR thermometer and the pipe by the otterstat is getting hot enough that it should be tripping. Dave S @ MW thinks it's possible the new otterstat may have failed so I'll try replacing it again. I ordered one of the new style ones with the screw-in otterstat from DeLorean Go just in case.

You'll also need the new "screw in pipe" for that screw-in Ostat to work. Hopefully, you ordered one of those as well.

[DaraSue]

You'll also need the new "screw in pipe" for that screw-in Ostat to work. Hopefully, you ordered one of those as well.

Yep! I got the expedited shipping so hopefully I get it by my day off next week. I had issues with the current one leaking when we changed it so I figured if all else fails I'll just change the whole pipe.

[hippieman9]

Yep! I got the expedited shipping so hopefully I get it by my day off next week. I had issues with the current one leaking when we changed it so I figured if all else fails I'll just change the whole pipe.

It comes together if you order the pipe.

[Bob635]

You still need to smog your car!!!!! I thought only us Californians were subject to totalitarian smog laws! Being at DCS this month, everybody from the Midwest was shocked that DeLoreans were still emissions tested.

Nevada is just like CA. Still tests cars all the way back to 1967! Just stupid and a waste of money. Makes political jobs and appoints.
It does nothing to improve air quality. This was proven in EPA research years ago. The impact of emission testing programs was less the 1% improvement. So a number of states ended testing for older cars. But still have the political
benefits from OBD II.

It is another case of people IGNORING the SCIENTIFIC FACTS for political gain and power. Gee, just like ignoring the science of Climate Change.

Bob

[eight8toy]

Just picked up my car here in San Diego for its SMOG today. Passed, whew.

The mechanic was able to make a few adjustments to get it tuned just right. I did give up on trying to get my O2 sensor out and had him do it since he had a lift. Ended up having to get the bung rewelded since it broke getting the old one out. But the car almost feels like it has more power now with the new sensor!

Hopefully in two years CA will get rid of the testing requirements for our cars, ya right....

[DaraSue]

Well, I think I figured put why the new otterstat crapped out...58149

The pipe wasn't looking too great. 58150 It doesn't really show in this pic but there was some deformation inside the opening so I'm thinking that's where it was leaking when we replaced it.

What are the chances that this rust is localized to just this pipe? Probably time for another coolant flush?

[hippieman9]

Well, I think I figured put why the new otterstat crapped out...58149

The pipe wasn't looking too great. 58150 It doesn't really show in this pic but there was some deformation inside the opening so I'm thinking that's where it was leaking when we replaced it.

What are the chances that this rust is localized to just this pipe? Probably time for another coolant flush?

I would flush the system good. The pipe is aluminum so it shouldn't rust.

[David T]

The aluminum pipes don't rust but they do develop pinholes. If you see that kind of gunk inside you have to figure it is all over the system. Flush each component separately. They sell stuff you can run in the system to break down the gunk and then flush you it out. The best way to flush is to use the cleaner and then do each thing by itself (the rad, the motor, the heater) backflush (reverse the flow). Changing the direction helps to get all of the gunk out. Best to temporally remove the thermostat so it doesn't get plugged up by all of the junk. If the gunk is like a jelly it is very old anti-freeze that was never flushed.

[DaraSue]

I've heard some people run a tab of dish detergent through their coolant system before flushing, has anybody tried this? What kind of detergent?

[Drive Stainless]

I've heard some people run a tab of dish detergent through their coolant system before flushing, has anybody tried this? What kind of detergent?

You can run Cascade dishwasher gel, NOT DISH DETERGENT, through it. It will clean a lot better than Prestone Cooling System flush. Use only 2 oz., go drive for an hour and then drain as soon as its cool enough.

Where I feel it beats the cooling system flush is it seems to do a great job suspending all of the trash within the liquid. So don’t delay draining it because you want to reduce the possibility that the trash will settle out.

It will not harm the plastic/rubber components since these materials are typically used in dishwashers.

[DaraSue]

A probably-insignificant but still unexpected plot development - I wanted to put it back together enough to flush it so I scraped out the pipe with a battery terminal brush and stuck the otterstat back in, then pumped the pressure tester to 10 and it didn't leak this time. :confused: I didn't think the lumpiness I was feeling inside the pipe opening last time was really going to come off and there was another nick in the pipe that I hadn't noticed before so IDK why it was leaking like a sieve and took 2 applications of sealant to stop it last time. I'll run it tomorrow and see if the fans come on now if it holds overnight.

58165

[David T]

You CANNOT use ANY sealant on that red seal for the "O" switch. It will cause the silicone seal to split.

[DaraSue]

I actually cleaned all the sealant off before I put it back in. It still wasn't working, though. I'll probably just wait to drain and flush it until the driving season is over. It performs normally temperature-wise under daily-driving conditions and I decided not to chance it driving to Vegas this week.

[DaraSue]

Back to the original problem, in a roundabout sort of way...

I got the Harbor Freight dwell meter and with the red lead connected to the orange wire in the blue church connector and the black wire grounded, it reads 54 with the RPM plug jumped. It does this even with the WOT switch unplugged. Dave S. said there's a temperature sensor in the engine that can cause this if it has a short in its wire. I'm guessing it's one of the ones under the intake?

Has this happened to anybody else before?

[opethmike]

Yes it is. And I'm telling you, you need to hug that car! Cars like hugs! I did my entire LS swap via hugs.

[dn010]

Yes it is. And I'm telling you, you need to hug that car! Cars like hugs! I did my entire LS swap via hugs.

+1

[NckT]

Back to the original problem, in a roundabout sort of way...

I got the Harbor Freight dwell meter and with the red lead connected to the orange wire in the blue church connector and the black wire grounded, it reads 54 with the RPM plug jumped. It does this even with the WOT switch unplugged. Dave S. said there's a temperature sensor in the engine that can cause this if it has a short in its wire. I'm guessing it's one of the ones under the intake?

Has this happened to anybody else before?

It will read 54 intil the coolant temperature reaches 80c. The lambda switch (temp switch) ilocated on tje V casting under the inlet manifold is ON until the temperature is above 80c, then the switch will go OFF. This lambda switch is wired in parallel with the full load wide open thrortle (WOT) switch, so if the WOT switch is unplugged yet the engine is not hot enough, you'll get 54.

Once the engine coolant temp is above 80c then week the fuel comport use the oxygen sensor as the reference signal and adjust the dwell accordingly to the current fuel mixture

[Bitsyncmaster]

It will read 54 intil the coolant temperature reaches 80c. The lambda switch (temp switch) ilocated on tje V casting under the inlet manifold is ON until the temperature is above 80c, then the switch will go OFF. This lambda switch is wired in parallel with the full load wide open thrortle (WOT) switch, so if the WOT switch is unplugged yet the engine is not hot enough, you'll get 54.

Once the engine coolant temp is above 80c then week the fuel comport use the oxygen sensor as the reference signal and adjust the dwell accordingly to the current fuel mixture

I don't think 80 C is a correct value. I hardly ever see 54 deg (60%) duty only in sub freezing weather.

[DaraSue]

Just tried adjusting and had to turn it clockwise to get it down into the 45-55 range. Do I need to compensate in some way for it reading high cold?

(I know it's supposed to be a last resort to mess with the mixture screw but the mechanic was messing with it when it was in the shop and he said he had it almost full lean at one point. It does seem less shaky after I adjusted it.)

Also I replaced the otterstat again and now my fans work, yay.

What's considered "high altitude"? My car was originally sold in TX and I'm at about 4500 ft here. AFAIK the high altitude adjustment prescribed in the service manual was never done when I brought it here.

(I gave it a hug, too. I'd post the proof but my webcam makes me look like some kind of demonic hellbeast.)

[opethmike]

I wouldn't check the reading or change the mixture until the car has warmed up.

[DaraSue]

I wouldn't check the reading or change the mixture until the car has warmed up.

I was following the steps in Dave S.'s article from an old DeLorean World that said to check it first with the engine off and the RPM relay jumped to engage the lambda system. It's supposed to read 45 like that. That was when it was reading 54 whether I had the WOT switch plugged in or not. The adjustments I made today were with it running hot enough to cycle the fans. I'm just wondering if whatever issue was causing the weird readings when it was cold is something I also have to factor in when it's hot? :headscratch:

[Bitsyncmaster]

Just tried adjusting and had to turn it clockwise to get it down into the 45-55 range. Do I need to compensate in some way for it reading high cold?

There is no adjustment for the cold engine dwell. Those values of cold and with WOT closed are preset values build into the lambda ECU.

[Ron]

I was following the steps in Dave S.'s article from an old DeLorean World that said to check it first with the engine off and the RPM relay jumped to engage the lambda system. It's supposed to read 45 like that. That was when it was reading 54 whether I had the WOT switch plugged in or not. The adjustments I made today were with it running hot enough to cycle the fans. I'm just wondering if whatever issue was causing the weird readings when it was cold is something I also have to factor in when it's hot? :headscratch:No, you don't...It is like Dave M said...

Check the chart out below:
"E:" shows the dwell should be 50-60 steady, until it is warm (15°C = 59°F).
So, 54 is OK, when cold.

"A:" shows the dwell should be 35-45 pulsating, when everything is normal including engine temp.
So, that's where 45 would be ~OK.
As mentioned, if it is staying at 54 under these conditions too, the LightGreen (LG) wire shared by the WOT and the Thermal Throttle Enrichment sensor/switch (in the valley) is shorted to ground, or, one of the two switches are activated. You can disconnect the LG wire from the Lambda ECU's pin #7 to eliminate all three cases....And it could be the ECU (easy to swap out for a test).

58183

[opethmike]

I think we should all hug Ron now.

[DaraSue]

I drove it to work today and it seemed fine. I'll recheck the dwell next time I have a day shift and can do it when I get home. I noticed after I got home tonight that the engine didn't seem to be vibrating at idle as much as it was before. Hopefully that's a good thing.