High idle troubleshooting

[Trstno1]

Ok guys.

I have just recently installed a DMC stage 1 exhaust. Since before then I had noticed a high idle with my car with a rich mixture. I sort of figured it may have been a plugged cat, which was one of the reasons I replaced my exhaust system. Unfortunately, the problems still exist even after the new exhaust.

When I go to cold start it, it seems to fire immediately but then die if I don't feather the gas pedal. Once it dies, I go to turn the car again and it will turn without fire for about 3-5 seconds, then roar to life. Once it does catch it runs like crap for a couple of seconds and then the idle stabilizes around 1k rpm. Though once I drive it, the idle will never go below 13-15k rpm. I have witnessed the idle throttle micro switch engaged when at idle, I just haven't tested any electrical aspect of the switch.

I have read other high idle threads and tried a couple of things in order to troubleshoot. I have unplugged the throttle control valve, but the idle stayed constant at 13k rpm. I plugged it back in and unplugged the new O2 sensor but with no change in idle as well. it doesn't even appear as thow the lambda system is working at all. Does anyone have any ideas as to how I can make sure the lambda system is working, and or how to get this high idle under control?

Thanks for any ideas in advance.

[Rich]

Let's work on the basics to start with.

You report seeing the idle microswitch being toggled when the engine is supposed to be idling. And then after you drive it a bit the idle goes up to 1300-1500RPM, right?

When it is idling at 1300-1500RPM please report whether the idle microswitch is still engaged. And if the throttle linkage is indeed closed in that condition.

The easy check during high idle is to to manually push the throttle closed at then last point in the linkage. If the idle drops then check your linkage/cable.


When I go to cold start it, it seems to fire immediately but then die if I don't feather the gas pedal. Once it dies, I go to turn the car again and it will turn without fire for about 3-5 seconds, then roar to life. Once it does catch it runs like crap for a couple of seconds and then the idle stabilizes around 1k rpm. Though once I drive it, the idle will never go below 13-15k rpm. I have witnessed the idle throttle micro switch engaged when at idle, I just haven't tested any electrical aspect of the switch.

[Jonathan]

The easy check during high idle is to to manually push the throttle closed at then last point in the linkage. If the idle drops then check your linkage/cable.

Rich is right. First things first. If it's high idling, stop and pull over, get out and push with your finger on the end of the pin that contacts the microswitch tab (backside of the end of the lever arm). You could also try to push down on the microswitch tab with a small screwdriver if by chance the rest screw is adjusted too far in and the actuating pin isn't reaching the microswitch tab because of that.

From my own experiences with high idles, if the idle you are hovering at isn't a fairly specific and consistent number (like 1,200 or 1,300 RPM as you said), it's probably throttle spool/linkage related. If it sits right at 2,000 RPM or 2,500 RPM every time, it's more likely a poor ECU connection somewhere or bad idle speed motor.

[BigBenb84]

I just resolved my high idle problem. Of course eliminate linkage/idle screws/microswitches as the culprit first. I was running too rich. Have you hooked a dwell meter to it? I bought one off eBay and hooked it up. Had to back out the mixture screw a lot till it started to cycle (freq valve buzzing) normally and the idle went back to normal. I have a thread w/video on here about it somewhere (I'm on the app now or else I would give the link).

[Trstno1]

[QUOTE=BigBenb84;174172]I just resolved my high idle problem. Of course eliminate linkage/idle screws/microswitches as the culprit first. I was running too rich. Have you hooked a dwell meter to it? I bought one off eBay and hooked it up. Had to back out the mixture screw a lot till it started to cycle (freq valve buzzing) normally and the idle went back to normal. I have a thread w/video on here about it somewhere (I'm on the app now or else I would give the link).[/QUO

I would be very interested in seeing that video as my car runs rich as well. Could you throw me a link when you get the chance?

Thanks,

[Trstno1]

Ok guys-

I just got around to actually investigating the micro switch only to realize two things. When at idle, the micro switch is being activated. Second, that the PO must have unplugged the micro switch as both spade terminals were unplugged!! I plugged it in and the idle immediately went from 1500 rpm to 1000 rpm just like that. Unfortunately, that's where it idles......1000 rpm. It still seems a bit high. Would there be any reason someone would unplug a micro switch? I did notice that when the car first started with the micro switch plugged in, it ran pretty crappy for a minute with the engine shaking a bit until it warmed up. I'll have to let it cool down again to see if the startup/ warmup behavior will be replicated.

As a side note: though I don't think this is the problem, I did recently installed a DMC type 1 exhaust. It also has a new O2 sensor. Though when running, unplugging the idle control valve or the O2 sensor results in no change to the idle. Is that normal? It still sits at 1k rpm. It also acted the same way prior to the exhaust change.


Second side note: I have always had a problem with the car starting and staying running the first time I turn the key. It will always fire within 1 second with what sounds like a strong start but then immediately die. The second time I turn the key, it will crank a second longer, and it will stumble to life and stay running though running rough. The vibration of the engine will shake the car. However, onece it warms up for about a minute the vibration goes away and the car seem to run fine for the most part. I have tried all conceivable combinations of babying the accelerator before the first start to keep it running the first time but very rarely can I get the timing just right to do so. What could that issue be? Fuel pressure? It still has the stock fuel pump setup. ( one of the only things I haven't replaced yet). Does the stock setup have a fuel check valve to keep the system pressurized?

Third side note: once the car has been running for awhile or has been driven, it will always hot start the first time and stay running without exception.


Anyone have any suggestions as to what my next step would be? Test the dwell? Put a check valve in for the fuel pressure? I would really like to get my car to start the first time, stay running, and idle normal.

Any suggestions would be greatly appreciated.

[Bitsyncmaster]

Unless you have my idle ECU, with the idle switch disconnected and engine warm you will get ignition advance and high, crappy idle.

You should be at 775 RPM idle speed. Try backing out the curb (lower) screw. You may have to also adjust the idle switch screw if you move the curb idle screw much.

Mixture adjustment is critical to get good cold engine running good. A lot of people just adjust it for best idle and that makes it way off.

Does your fuel pump prime (run for a second) when you just turn the key from off to on?

[Trstno1]

Unless you have my idle ECU, with the idle switch disconnected and engine warm you will get ignition advance and high, crappy idle.

You should be at 775 RPM idle speed. Try backing out the curb (lower) screw. You may have to also adjust the idle switch screw if you move the curb idle screw much.

Mixture adjustment is critical to get good cold engine running good. A lot of people just adjust it for best idle and that makes it way off.

Does your fuel pump prime (run for a second) when you just turn the key from off to on?

Yes the fuel pump primes. I can hear it when I turn the ignition on prior to crank. However, it doesn't matter if I wait for the cycle to complete or not....it still dies directly after cold startup. Is the curb screw the lower screw on the the micro switch bracket? Sorry I'm still a newbie...

[Bitsyncmaster]

Is the curb screw the lower screw on the the micro switch bracket? Sorry I'm still a newbie...

Yes

[DMC5180]

Just ensure the lower adjusting screw is not contacting the bracket (throttle plates closed) and make sure the upper screw still triggers the micro-switch.

Your cold start issue could be attributed to a leaking injector. The next time your do a cold start try pressing down on the the gas pedal a little after it the engine fires. See if that clears the initial rough idle then let off the pedal to see if the idle is stable @ 775 +- 25.

[Jonathan]

For understanding that "upper screw, lower screw" idea, have a look at this pictures in this post:

http://dmctalk.org/showthread.php?10336-Assorted-helpful-technical-photos&p=152181&viewfull=1#post152181

You can see it best in the 3rd and 4th pictures. The bracket holding those two screws (upper to engage the microswitch, lower to bottom out or come to rest at a zero point/curb screw) pivots together with the butterfly valves that are inside. As Dennis was saying, you want the lower curb screw to rest against its stop right where the butterfly valves are fully closed (i.e. in a vertical position). Once you're happy with that, adjust the upper microswitch screw to just activate the metal tab on the microswitch and then make it protrude perhaps another quarter turn or so.

When you're sitting at idle at a red light or intersection, you want the microswitch to be engaged at the same time the butterfly valves are completely closed and not letting any air by them. What I think can happen to change things slightly (and inconsistently), is if your pivot point and linkage aren't cleaned up well or lubed to some degree, the resistance normally put on by that spring to get it to go back to zero is countered by grime or rust or whatever and then it doesn't come all the way back.

This seems to happen more when the engine is warm or hot which is either affecting the spring or the grime by it expanding or swelling in the heat or it's being affected by the vacuum system somehow getting stronger as the engine has warmed up. This "sticking" idle is what you'll be dealing with if you need to "snap the gas" to get it to come back down. If giving the accelerator a quick snap or two to get it to come down works, then something in that throttle assembly and linkage isn't rotating freely. If the high idle is perma-stuck at 2,000 RPM or something similar, it's generally going to be an electrical connection gone bad.

Speaking of which, you mentioned your connector on that microswitch. Do you have a manual trans? I think you do, wasn't sure though. The automatics also have a "full throttle microswitch" which is very similar in terms of the switch and connector and it is mounted on the side of the throttle spool at about the 10 o'clock position looking down on it.

On the automatics, if you hammer the gas say in 3rd gear while out on the highway pulling out to pass someone, it will kick down the trans to 2nd to give you some more oomph to pass. I don't think the manual trans cars have this microswitch but I think they may still have the connector (not sure about that though). Some owner before you might have confused the two microswitches or connectors to explain why yours was unplugged. Hard to say though for sure.

[DMC5180]

All D's came with a full throttle enrichment switch. The automatics have an additional kick down switch. Manual cars just have the unused kick down switch connector stowed.

[Jonathan]

All D's came with a full throttle enrichment switch. The automatics have an additional kick down switch. Manual cars just have the unused kick down switch connector stowed.

Thanks for clarifying. Those two switches on the autos are "stacked" on top of each other, aren't they? The kickdown and full throttle ones that is.

Are any of the electrical connectors for these two or three switches universal such that the OP might have them plugged in to the wrong spot accidentally?

[DMC5180]

Stacked? Yes.

Connectors are the same style, but different colors. One black (kick down) and one white (enrichment).

[Trstno1]

Just ensure the lower adjusting screw is not contacting the bracket (throttle plates closed) and make sure the upper screw still triggers the micro-switch.

Your cold start issue could be attributed to a leaking injector. The next time your do a cold start try pressing down on the the gas pedal a little after it the engine fires. See if that clears the initial rough idle then let off the pedal to see if the idle is stable @ 775 +- 25.

Ok, it appears as though the curb screw is just barely making contact with the plate when the throttle is fully closed. So I don't want to mess with it quite yet. At this point it appears to be idling at 775-800 rpm after a second test from plugging the micro switch back in. That's good. Now, back to the original issue. Rich running. The dwell tested at 42-48 warm. Is that good or bad? I have never heard my FV buzz at all, ever.... I have verified power to the FV and the lambda ECU when the engine is running so my lambda relay, rpm relay, and lambda ecu should be working right? The only thing that seems weird is that after it warms up (still running rich) I can unplug the O2 sensor with no change to idle or running rich smell. Same story for the idle control valve. Is that normal? Meanwhile the FV never seems to buzz. Though I must admit I'm not sure of what the sound should be simply because being over a running motor with a type 1 exhaust installed is already a bit loud. I assume if the FV is not obviously buzzing, the ECU already thinks the car is running rich right? Is there a test I can conduct to lean things out a bit to see if that helps the running rich smell and turns the FV on? i have a pic of the throttle plate I'll attach, and I have some videos as well that may help in diagnosis if I can figure out how to attch them....

All help is greatly appreciated!

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[Trstno1]

For understanding that "upper screw, lower screw" idea, have a look at this pictures in this post:

http://dmctalk.org/showthread.php?10336-Assorted-helpful-technical-photos&p=152181&viewfull=1#post152181

You can see it best in the 3rd and 4th pictures. The bracket holding those two screws (upper to engage the microswitch, lower to bottom out or come to rest at a zero point/curb screw) pivots together with the butterfly valves that are inside. As Dennis was saying, you want the lower curb screw to rest against its stop right where the butterfly valves are fully closed (i.e. in a vertical position). Once you're happy with that, adjust the upper microswitch screw to just activate the metal tab on the microswitch and then make it protrude perhaps another quarter turn or so.

When you're sitting at idle at a red light or intersection, you want the microswitch to be engaged at the same time the butterfly valves are completely closed and not letting any air by them. What I think can happen to change things slightly (and inconsistently), is if your pivot point and linkage aren't cleaned up well or lubed to some degree, the resistance normally put on by that spring to get it to go back to zero is countered by grime or rust or whatever and then it doesn't come all the way back.

This seems to happen more when the engine is warm or hot which is either affecting the spring or the grime by it expanding or swelling in the heat or it's being affected by the vacuum system somehow getting stronger as the engine has warmed up. This "sticking" idle is what you'll be dealing with if you need to "snap the gas" to get it to come back down. If giving the accelerator a quick snap or two to get it to come down works, then something in that throttle assembly and linkage isn't rotating freely. If the high idle is perma-stuck at 2,000 RPM or something similar, it's generally going to be an electrical connection gone bad.

Speaking of which, you mentioned your connector on that microswitch. Do you have a manual trans? I think you do, wasn't sure though. The automatics also have a "full throttle microswitch" which is very similar in terms of the switch and connector and it is mounted on the side of the throttle spool at about the 10 o'clock position looking down on it.

On the automatics, if you hammer the gas say in 3rd gear while out on the highway pulling out to pass someone, it will kick down the trans to 2nd to give you some more oomph to pass. I don't think the manual trans cars have this microswitch but I think they may still have the connector (not sure about that though). Some owner before you might have confused the two microswitches or connectors to explain why yours was unplugged. Hard to say though for sure.

I do have a manual yes.

[Trstno1]

Just ensure the lower adjusting screw is not contacting the bracket (throttle plates closed) and make sure the upper screw still triggers the micro-switch.

Your cold start issue could be attributed to a leaking injector. The next time your do a cold start try pressing down on the the gas pedal a little after it the engine fires. See if that clears the initial rough idle then let off the pedal to see if the idle is stable @ 775 +- 25.

Ok, so I've tested it a couple of times with the same results. I can barely press in on the accelerator when I cold start it and it will stay running, when I let off of the peddle after it appears as though it should be fine it bobbles down to about 500 rpm for a second almost dying then stabilizes back up to around 775 rpm. What do you think? Vacuum issue, fuel pressure issue, or leaky injector?

[Bitsyncmaster]

Ok, so I've tested it a couple of times with the same results. I can barely press in on the accelerator when I cold start it and it will stay running, when I let off of the peddle after it appears as though it should be fine it bobbles down to about 500 rpm for a second almost dying then stabilizes back up to around 775 rpm. What do you think? Vacuum issue, fuel pressure issue, or leaky injector?

Have you looked at the screen filter in the warmup regulator?

[Trstno1]

Have you looked at the screen filter in the warmup regulator?

I have not. Is that something that can be got
To fairly easily? What does the warm up regulator do exactly, and what would the symptoms of a clogged filter be?

[Bitsyncmaster]

I have not. Is that something that can be got
To fairly easily? What does the warm up regulator do exactly, and what would the symptoms of a clogged filter be?

You pull the fuel hose from the fuel distributor to the WUR and look down into the WUR. If it's dirty, you use some air and a brush to clean it off while still in the WUR. Probably best to pull the WUR out of the car so you can see what your doing.

The WUR sets the mixture rich when the engine is cold. It does what a choke does on a carburetor.

[DMC5180]

You pull the fuel hose from the fuel distributor to the WUR and look down into the WUR. If it's dirty, you use some air and a brush to clean it off while still in the WUR. Probably best to pull the WUR out of the car so you can see what your doing.

The WUR sets the mixture rich when the engine is cold. It does what a choke does on a carburetor.

If not familiar with fuel system components,
The WUR/CPR is bolted to the LH rocker cover. You remove the larger fuel line banjo bolt. The screen is at the bottom of that port.

If you break the connection you should replace the copper sealing washers.

[Delorean Industries]

Must* Never reuse banjos.

[Trstno1]

If not familiar with fuel system components,
The WUR/CPR is bolted to the LH rocker cover. You remove the larger fuel line banjo bolt. The screen is at the bottom of that port.

If you break the connection you should replace the copper sealing washers.

Do you guys have a part number for the copper sealing washer? Will that be the same copper washers that are on the rest of the banjo bolts going into the fuel distributer?

[Trstno1]

Must* Never reuse banjos.

Never re-use banjo bolts? Or washers? What?

[Trstno1]

So is this the CO adjustment hole? I have heard people saying this hole should have been plugged? Mine was definitely not plugged up. I also can't seem to find an Allen wrench that fits to turn anything inside that hole. I can barely look in the hole but don't see any female Allen head at all..... What sort of tool do I need.
3522935230

[acaciolo]

you need a long 3mm t handle allen wrench. Sears has them. You absolutely need that plugged. A bolt or golf tee works. DMC also has a little plug with a wire loop on it. Without it plugged, you have a vacuum leak.

[Trstno1]

you need a long 3mm t handle allen wrench. Sears has them. You absolutely need that plugged. A bolt or golf tee works. DMC also has a little plug with a wire loop on it. Without it plugged, you have a vacuum leak.

That's what I thought. I just noticed it and was playing around with plugging it with my finger, but didn't notice a difference in idle at all. Weird..... Do you happen to have the DMC part number for the plug?

[acaciolo]

here you go:

https://store.delorean.com/p-6399-plug-removeable.aspx

[Trstno1]

That's what I thought. I just noticed it and was playing around with plugging it with my finger, but didn't notice a difference in idle at all. Weird..... Do you happen to have the DMC part number for the plug?

I think I found the reason no tool would fit...... Is this the plug everyone is talking about drilling out? It looks like the PO attempted, but gave up prior to tapping though. I suppose that would also explain why I didn't have a vacuum leak with the upper hole unplugged. Either that, or the PO iwas an idiot and tried to drill out an Allen hole? Guesses?

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[Bitsyncmaster]

I think I found the reason no tool would fit...... Is this the plug everyone is talking about drilling out? It looks like the PO attempted, but gave up prior to tapping though. I suppose that would also explain why I didn't have a vacuum leak with the upper hole unplugged. Either that, or the PO iwas an idiot and tried to drill out an Allen hole? Guesses?

35231

Your plug was drilled out in your first photo. This photo looks like the PO drilled to deep into the 3 mm "Allen" head bolt.

[Trstno1]

Your plug was drilled out in your first photo. This photo looks like the PO drilled to deep into the 3 mm "Allen" head bolt.

Oh no! :smashfreak: I suppose you can't get the 3mm head out without taking off the whole assembly right? Do they sell just that part or am I up a creek here?

[Jonathan]

...At this point it appears to be idling at 775-800 rpm after a second test from plugging the micro switch back in.


Ok, so I've tested it a couple of times with the same results. I can barely press in on the accelerator when I cold start it and it will stay running, when I let off of the peddle after it appears as though it should be fine it bobbles down to about 500 rpm for a second almost dying then stabilizes back up to around 775 rpm. What do you think? Vacuum issue, fuel pressure issue, or leaky injector?

If you meant plugging the microswitch back in a second time helped because perhaps the connectors were a bit corroded or not making good contact... you might want to do the same with the electrical connector on top of the idle speed motor (ISM). Take it off, put it back, take it off, put it back on, etc. Check the same with the connections at the bulkhead corner. Your car dipping down to 500 RPM momentarily for no good reason might be saying the electrical connection is flakey/inconsistent. It's also a lot easier initially than breaking into fuel lines in case you do end up needing to do that as well.

[Bitsyncmaster]

Oh no! :smashfreak: I suppose you can't get the 3mm head out without taking off the whole assembly right? Do they sell just that part or am I up a creek here?

I would think you will need to take it all apart. Don't know if it's just a standard bolt but some "handyman" should be able to come up with a fix.

[DMC5180]

Oh no! :smashfreak: I suppose you can't get the 3mm head out without taking off the whole assembly right? Do they sell just that part or am I up a creek here?

Do you have a 3 mm hex t- handle? Just looking at the photo you may still have enough of a pocket in the set screw to still be able to get the wrench to bite into it. Worst case you will need to find a used metering unit. Luckily that should not be to difficult with all carb and EFI conversion people out there.

[Trstno1]

Do you have a 3 mm hex t- handle? Just looking at the photo you may still have enough of a pocket in the set screw to still be able to get the wrench to bite into it. Worst case you will need to find a used metering unit. Luckily that should not be to difficult with all carb and EFI conversion people out there.

True! I will try that!

Thanks

[Trstno1]

So I have made a couple of Dwell reading videos I would be greatfull if you guys would ponder. If I don't have to attempt to mess with the mixture I wont. If I do, I will start looking for a solution.

Video #1 - this is a video of the dwell readings right after a cold start.

https://www.youtube.com/watch?v=bTgjTItnGWY


Video #2 - this is a video of the dwell readings while it was still warming up. I was just putting on my shoes to take if for a test drive, when this happened.

https://www.youtube.com/watch?v=m8nnjXiVgMc


Video #3 - this is a video of the dwell readings after coming back from a drive.

https://www.youtube.com/watch?v=deo6DKSu2QM

At this point, the idle is much better but just below 1k after a drive. The rich running smell is much better now as well since I have replaced the FV connector and plugged in the micro switch. At this point I am just trying to establish whether or not the car is running rich or lean. BTW, I did plug the hole as to eliminate a vacuum leak at the mixture hole.

Thanks for your time.

[DMC5180]

What did you plug the hole with?

[acaciolo]

Mine was acting funny like that also. I was having a heck of a time getting a good sweeping needle for the dwell reading. It would spike just like yours.

So I got an automotive stethoscope and started listening for vacuum leaks. I heard a loud whistle near one of the injectors, but I wanted to be sure.

so I fabricated a smoke machine out of a paint can (lantern wick, wire connected to 12v, with mineral oil inside.) I pulled off the hose from the oil filler and attached the smoke input there (I pushed about 1 psi of air filled with smoke into the engine.) I found my vacuum leak, sealed it, and now my dwell reading is spot on

Just to be on the safe side, I tested it with a wideband meter also stuck into the exhaust pipe (big thanks to Josh at dpi for hooking me up with this.) I got a 14.7 air fuel ratio reading at the exhaust right when my dwell was sweeping around 45 ( 5 degrees each way, roughly.) So for me, solving the vacuum leak cleared up my erratic idling/strange dwell reading.

also, for some reason, I no longer get a dwell reading at the diagnostic port. I can only read it at the orange wire on the blue bulkhead connector.

[Jonathan]

Did you plug that mixture adjustment hole already? Stick a wad of chewing gum in it for the time being if you need to.

Also, could you perhaps shoot a short video of the engine running, but then film various areas around the engine to show other connections as maybe someone spots something not plugged in correctly or otherwise out of place?

[Trstno1]

What did you plug the hole with?

I plugged it with a random electrical wiring connector I had laying around. Seems like it plugged the hole fairly well. But then again I never noticed a difference when plugging the hole with my finger either....

[Trstno1]

Did you plug that mixture adjustment hole already? Stick a wad of chewing gum in it for the time being if you need to.

Also, could you perhaps shoot a short video of the engine running, but then film various areas around the engine to show other connections as maybe someone spots something not plugged in correctly or otherwise out of place?

Will do! I'll post it tomorrow.

[Bitsyncmaster]

It looks like your lambda system is working correctly. You probably need to set the dwell to get a little higher reading but I would think your engine should run good as is.

You may need to clean your idle motor to get the cold running swinging dwell a little more stable.

You also may need to install a new O2 sensor which may help stabilize the dwell and idle RPM a little more.

I fought with high idle RPM on my car when the engine was fully warmed up. It turned out to be the bad deceleration springs on the throttle plates. If you think that could be your problem, you pull the W pipe and get a photo of those springs. If the spacing on the spring is not even, you most likely have the bad springs.

[Trstno1]

It looks like your lambda system is working correctly. You probably need to set the dwell to get a little higher reading but I would think your engine should run good as is.

You may need to clean your idle motor to get the cold running swinging dwell a little more stable.

You also may need to install a new O2 sensor which may help stabilize the dwell and idle RPM a little more.

I fought with high idle RPM on my car when the engine was fully warmed up. It turned out to be the bad deceleration springs on the throttle plates. If you think that could be your problem, you pull the W pipe and get a photo of those springs. If the spacing on the spring is not even, you most likely have the bad springs.

Thanks for the tip! Any idea reagarding why it immediately dies when it first starts?

[DMC5180]

Does it do that for every cold start day to day? How is it say an hour from one start to the next?

[Bitsyncmaster]

Thanks for the tip! Any idea reagarding why it immediately dies when it first starts?

First thing to find cold start issues is get a gauge on the fuel system to check control pressure when cold. Control pressure starts very low about 20 PSI and rises pretty quickly. It then settles around 50 PSI when the engine is warm.

[Trstno1]

Does it do that for every cold start day to day? How is it say an hour from one start to the next?

Yes, every cold start it will turn and fire but immediately die. If I baby the gas it will stay running, but once foot is removed from the gas the engine will bobble around 500 rpm for a couple of seconds then go up to 775ish. If upon the second attempt at startup I don't touch the gas pedal the car will crank then eventually fire and exhibit the same symptoms as stated above.

If I start it later after its already been running, the car will fire strait away and stay running. So I'm not sure if that's a symptom of fuel pressure or vacuum leaks....

I guess I just want the car to start and stay running the first time. It's kind of a bummer at shows when everyone is looking at your car while you are getting ready to leave and it dies the first time you start it. Embarrassing......

[Trstno1]

Did you plug that mixture adjustment hole already? Stick a wad of chewing gum in it for the time being if you need to.

Also, could you perhaps shoot a short video of the engine running, but then film various areas around the engine to show other connections as maybe someone spots something not plugged in correctly or otherwise out of place?

here you go!

https://www.youtube.com/watch?v=LGcbxHmSyZk&feature=youtu.be

[Jonathan]

here you go!

https://www.youtube.com/watch?v=LGcbxHmSyZk&feature=youtu.be

Double check something for me:

See this connector?

35269

It looks a lot like the type that should have a home.

See if it is the one labelled as 53 and 54 on this bulkhead diagram:

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That is labelled as for the frequency valve, so important enough to confirm all is well there.

[Jonathan]

Ok, nevermind, it isn't.

35271

It still seems like something that should be going somewhere I just don't know where yet...

[DMC5180]

What color are the wires in that 2 way connector ? I can't view the video at the moment (cellular data issue)

[Jonathan]

What color are the wires in that 2 way connector ? I can't view the video at the moment (cellular data issue)

I have a hard time making it out from the video, but at least one of the wires looks red. The connector looks almost like the one going to the driver's seatbelt receptacle, but that doesn't make a lot of sense back there. I can't think of any others quite like it behind the engine. The connector back there that is normal to be unplugged has a couple green wires on it and has that clasp on either side of the plastic to clip it tight together with. That's in a different part of the engine view though.

Trstn, can you take a close up photo of the connectors on your idle microswitch and post? It just looks to me like something is missing there and I'm not sure if it is only me getting confused because half the connector is black and they are white on my car.

[DMC5180]

Red and black wires is an unused connector (homeless)

The green wires connector is for reverse light switch harness to the transmission and should be connected.

Half black / half white connector? Full throttle (enrichment) micro switch has a white connector and should have a corresponding white connector on the engine harness. The black connector is supposed to match up with the full throttle ( kick down) switch if you have an automatic trans.
Dennis

[Trstno1]

I have a hard time making it out from the video, but at least one of the wires looks red. The connector looks almost like the one going to the driver's seatbelt receptacle, but that doesn't make a lot of sense back there. I can't think of any others quite like it behind the engine. The connector back there that is normal to be unplugged has a couple green wires on it and has that clasp on either side of the plastic to clip it tight together with. That's in a different part of the engine view though.

Trstn, can you take a close up photo of the connectors on your idle microswitch and post? It just looks to me like something is missing there and I'm not sure if it is only me getting confused because half the connector is black and they are white on my car.

Here tiz.....

The white connector goes to the full throttle switch, nothing connected to the black plug. The idle micro switch has its own wiring.

3527635277

[DMC5180]

Yep that's the correct 5 speed setup.

[Trstno1]

What color are the wires in that 2 way connector ? I can't view the video at the moment (cellular data issue)

Colors are red & black. But I guess people are saying its a homeless plug.

35278

[DMC5180]

Unused connector, no one seems to no what it might have been intended for either.

[Trstno1]

Red and black wires is an unused connector (homeless)

The green wires connector is for reverse light switch harness to the transmission and should be connected.

Half black / half white connector? Full throttle (enrichment) micro switch has a white connector and should have a corresponding white connector on the engine harness. The black connector is supposed to match up with the full throttle ( kick down) switch if you have an automatic trans.
Dennis



It appears as though the other plugs are in order since I have a manual. Thanks for the info!

[DMC5180]

I was referring to Jonathan's statement where he said the green wires connector should be disconnected.

[Trstno1]

First thing to find cold start issues is get a gauge on the fuel system to check control pressure when cold. Control pressure starts very low about 20 PSI and rises pretty quickly. It then settles around 50 PSI when the engine is warm.

Would this just be one of the fuel pressure kits that Hervy sells? If the pressure is too low cold is that the reason for the start and die on first attempt. Would that be a fuel pump issue, a check valve issue, or a control pressure regulator issue?

[Bitsyncmaster]

Would this just be one of the fuel pressure kits that Hervy sells? If the pressure is too low cold is that the reason for the start and die on first attempt. Would that be a fuel pump issue, a check valve issue, or a control pressure regulator issue?

I think all the K-jet pressure test gauges can read control pressure (you open the valve on the tester).

The service book shows tables of control pressure. If it does not fit those values it's the control pressure regulator. But make sure you have heater power before you buy a new CPR.

[Horsebox]

I had something similar with mine. During winter it would fire immediately and then die. Try again and hold the gas down to keep the revs up for 30 secs or so then it would stay running on its own.

Turned out the CPR was massively over leaning, but the only way to know this is a fuel pressure testing kit for k jet. Stethoscope for D owners!

I know it looks and smells like it's running rich but the fuel pressure gauge will reveal a lot. Has your car sat for a long time at some point without being properly sorted?

When I got my car it had sat for a while, but it ran ok and started instantly, except during the winter when it would die straight away unless you held the throttle open for 30 secs or so. Took me 18 months to get there but every part of the the fuelling was wrong, except the distributor.

If your car has sat for ages, with hindsight from my limited ! experience, strip all of the fuelling out and have it rebuilt, you'll probably need new injectors, check the electrics to the fuel pump., to make sure it's getting the power it needs under an 8 amp load.

[Trstno1]

I had something similar with mine. During winter it would fire immediately and then die. Try again and hold the gas down to keep the revs up for 30 secs or so then it would stay running on its own.

Turned out the CPR was massively over leaning, but the only way to know this is a fuel pressure testing kit for k jet. Stethoscope for D owners!

I know it looks and smells like it's running rich but the fuel pressure gauge will reveal a lot. Has your car sat for a long time at some point without being properly sorted?

When I got my car it had sat for a while, but it ran ok and started instantly, except during the winter when it would die straight away unless you held the throttle open for 30 secs or so. Took me 18 months to get there but every part of the the fuelling was wrong, except the distributor.

If your car has sat for ages, with hindsight from my limited ! experience, strip all of the fuelling out and have it rebuilt, you'll probably need new injectors, check the electrics to the fuel pump., to make sure it's getting the power it needs under an 8 amp load.

Where and how do you hook up a fuel pressure gauge? That sounds like that may be the next step. When I purchased my car, the PO stated that he didnt drive it much but started it fairly consistently in order to make sure the fuel never got stale. But who know really right? How did you fix the CPR massively over leaning? Replace it?

[Horsebox]

I'm pretty sure from memory the gauge sits between the return line from the CPR and the distributor. It has a valve that you can shut off to eliminate the control pressure so you are then reading primary pressure. Any pressure testing kit you buy will have instructions, it's not hard. Just don't start undoing banjo bolts with fuel under residual pressure and a hot engine!

Yeah the CPR has a spring in it, which had broken, so I sent the whole thing to a specialist and it came back like new.

Fuelling seems to be the biggest problem with these cars, as many have sat for months or years. I know you don't want to hear it but to sort it once and for all start at the tank, pull everything out, clean the tank, then deal with the fuel injection components. Otherwise you can fix broken components only to pollute them with dirty fuel.