Dwell Stuck at 50% am I correct to suspect the O2 sensor?

[spikeygg]

My car has a very hard time starting. I have aftermarket cams which make the idle very lopey, I don't know for sure but I'm guessing this means I need more fuel than an OEM cam'd car. I put an o-scope and the dwell meter on the thing today and it's stuck at 50% duty cycle when the car is completely warmed up.

Anyone know if I can replace the lambda o2 sensor with this cheapo one from AutoZone (https://www.autozone.com/engine-management/oxygen-sensor/bosch-exact-fit-oxygen-sensor-12014/4970_660383_18264_8606_97999)?

Thanks,
-Greg

[Ron]

This is the one AutoZone says will fit. (https://www.autozone.com/engine-management/oxygen-sensor/bosch-exact-fit-oxygen-sensor-11032/231819_659651_18264)

It basically has no affect on the engine while cold or during starting because the sensor must see 572°F (300°C) minimum...

FWIW, steady 50% duty cycle could be:
No signal from the O2 sensor (bad sensor or wiring open), WSM D:04:15
WOT switch stuck/shorted internally, wiring shorted to ground. WSM D:04:15
(https://www.autozone.com/engine-management/oxygen-sensor/bosch-exact-fit-oxygen-sensor-11032/231819_659651_18264)

[spikeygg]

This is the one AutoZone says will fit. (https://www.autozone.com/engine-management/oxygen-sensor/bosch-exact-fit-oxygen-sensor-11032/231819_659651_18264)

It basically has no affect on the engine while cold or during starting because the sensor must see 572°F (300°C) minimum...

FWIW, steady 50% duty cycle could be:
No signal from the O2 sensor (bad sensor or wiring open), WSM D:04:15
WOT switch stuck/shorted internally, wiring shorted to ground. WSM D:04:15
(https://www.autozone.com/engine-management/oxygen-sensor/bosch-exact-fit-oxygen-sensor-11032/231819_659651_18264)

Thanks Ron, I went out and bought the O2 sensor I posted before for $16 and just cut the end off and soldered on the end from my old one. I took the car for a spin and got it all warmed up and then set up my o-scope to measure the dwell. I was able to tweak it into the a range of ~34% - ~58% according to the duty cycle calculation -- does that sound about right?

Here's a video of my tune after warming it up:

https://www.youtube.com/watch?v=JkYXK1MILGw

I'm curious about this because it seems like once I get the fuel mixture set properly it seems my car will not start. It's like it doesn't have enough cranking fuel. I'm wondering if it's because of the hot cams... unfortunately this has always been a problem so I'm not sure how to solve it properly. Any ideas?

[spikeygg]

Here's a video of the first two cold start attempts:

https://www.youtube.com/watch?v=kk8oAGfF1Gg

[Michael]

I find that anything other than an analogue meter is hard to set the mixture with but I'm not that smart. Watching that needle swing makes it easier (for me anyway).

As far as your cold start goes, two or three things;
Check your battery voltage and charge if needed. Sounds like it's cranking slow and your volt gauge looks pretty low. I found with mine that it started a lot easier when the alternator was functioning properly. Cleaning the ground on the frame below the expansion tank could also help as well as the one on the radiator bracket.

Also look at the o rings in the primary pressure regulator in the fuel distributer. If they are old just replace them because even the smallest imperfection or damage can cause a hard hot start but if they are really bad it will also affect cold start. Thing is there is no way to really check them without removing them and they get hard and brittle when old. It's a cheap and very easy fix but be sure you know that the plunger is spring loaded when you remove that nut.

I would not worry too much about mixture setting right now. Once you fix your cold start issue and possible other problems such as a vacuum leak, etc. The mixture is usually the last thing you do.

[dmcnc]

By hot cams, you mean non-OE cams? Timing could be a factor.

[David T]

Hard cold starting usually means a problem with the cold start valve or other associated parts like the TTS or the wiring. If you have the duty cycle set, leave it alone. If you have after-market cams you may need to adjust the base timing. While checking the timing you should check the mechanical and vacuum advance to make sure they are working properly. The dwell or O2 sensor has no effect on cold starts. If the battery or any connections are not good and the voltage drops low enough the ignition ECU won't work so that means no spark and no start. The main thing that controls the motor during warm-up is the CPR. To test if the cold start system is working, do the plug swap. If the cold motor starts easier then figure out why the CSV is not working right.

[Ron]

Thanks Ron, I went out and bought the O2 sensor I posted before for $16 and just cut the end off and soldered on the end from my old one. I took the car for a spin and got it all warmed up and then set up my o-scope to measure the dwell. I was able to tweak it into the a range of ~34% - ~58% according to the duty cycle calculation -- does that sound about right?

Here's a video of my tune after warming it up:

I'm curious about this because it seems like once I get the fuel mixture set properly it seems my car will not start. It's like it doesn't have enough cranking fuel. I'm wondering if it's because of the hot cams... unfortunately this has always been a problem so I'm not sure how to solve it properly. Any ideas?Yes, that sounds very close to ideal for stock DutyCycle (pulsating, centered at 44.44%, hot).

Seems to be some confusion... Are/were you having starting problems hot and cold?

Your temp, volts, and RPM all look low to me in the vid.
Let the fans cycle a couple of times to ensure everything is warm. Use a reliable meter for volts & RPM. Set CO last, as Michael suggested, ALWAYS. (Again, it's not the cause of starting problems.)

If all of the basic settings are to spec, I'd suggest checking the Control and Primary pressures (Don't disturb the PPR valve unless pressure is incorrect.)

At this point, I agree with the WUR/CPR or timing as primary suspects. If cold start problems only, I'd add the CSV as David suggested.

[Bitsyncmaster]

Electronic instruments use positive pulse timing for duty cycle numbers and automotive instruments use the negative pulses. So when your scope says 40% your really at 60%. With your wide open throttle switch pressed you are running at 60% solid. So press it and I bet your scope says 40%.

So your looking to have the scope reading centered around 60%.

[spikeygg]

Electronic instruments use positive pulse timing for duty cycle numbers and automotive instruments use the negative pulses. So when your scope says 40% your really at 60%. With your wide open throttle switch pressed you are running at 60% solid. So press it and I bet your scope says 40%.

So your looking to have the scope reading centered around 60%.

Crap, I was worried about that. I can measure +Duty and/or -Duty on the scope and I chose +Duty because I wasn't sure if it should be high time or low time. Unfortunately, I removed my WOT switch from my car -- it was broken and causing other issues. Can I just ground the WOT pin to enable the WOT mode? Or maybe I need to short the two pins together? That should be an easy way to check.

[spikeygg]

By hot cams, you mean non-OE cams? Timing could be a factor.

yeah, non-OE cams. I set the timing back when I finished the rebuild a few years ago but it's a good call out. I should verify that the timing is correct. Any idea what it should be for non-OE cams?

[spikeygg]

I find that anything other than an analogue meter is hard to set the mixture with but I'm not that smart. Watching that needle swing makes it easier (for me anyway).

As far as your cold start goes, two or three things;
Check your battery voltage and charge if needed. Sounds like it's cranking slow and your volt gauge looks pretty low. I found with mine that it started a lot easier when the alternator was functioning properly. Cleaning the ground on the frame below the expansion tank could also help as well as the one on the radiator bracket.

Cool, I'll check these spots. Regarding the voltage, I always have the car hooked up to a battery tender so it *should* be charged. I took the battery and alternator out to AutoZone about 6 months ago to have them both tested and confirmed that they were both in good working order.


Also look at the o rings in the primary pressure regulator in the fuel distributer. If they are old just replace them because even the smallest imperfection or damage can cause a hard hot start but if they are really bad it will also affect cold start. Thing is there is no way to really check them without removing them and they get hard and brittle when old. It's a cheap and very easy fix but be sure you know that the plunger is spring loaded when you remove that nut.

I would not worry too much about mixture setting right now. Once you fix your cold start issue and possible other problems such as a vacuum leak, etc. The mixture is usually the last thing you do.

As it turns out the hot start is easier than the cold start in this case. Should I skip the o-rings based on that? I've never opened the fuel distributor before... I'll have to see if I can find a youtube video on that.

[spikeygg]

Hard cold starting usually means a problem with the cold start valve or other associated parts like the TTS or the wiring. If you have the duty cycle set, leave it alone. If you have after-market cams you may need to adjust the base timing. While checking the timing you should check the mechanical and vacuum advance to make sure they are working properly. The dwell or O2 sensor has no effect on cold starts. If the battery or any connections are not good and the voltage drops low enough the ignition ECU won't work so that means no spark and no start.

I can check the timing easy enough but how do I check the mechanical and vacuum advance?


The main thing that controls the motor during warm-up is the CPR. To test if the cold start system is working, do the plug swap. If the cold motor starts easier then figure out why the CSV is not working right.

Maybe I'm missing something but you said previously (http://dmctalk.org/showthread.php?13907-quot-Plug-Swap-quot) that the "plug swap" was intended to check hot start issues, not cold start issues:


The "plug Swap" is mainly intended to start the motor if you have a hard hot restart problem, not a cold start problem. If doing the plug swap helps fix the cold start problem that means you have a wiring problem or a bad TTS switch in the cold start valve system. When cold the cold start valve is supposed to be opened during cranking by the Thermo-Time Switch. Doing the plug swap bypasses the TTS and the wiring, running the Cold Start Valve directly. Once the car starts you must quickly put the plugs back or you will flood the motor with excess fuel. The plug to the TTS has a polarity and MUST be installed correctly or you will burn up the TTS. The TTS MUST be grounded, installing it with Teflon tape is a bad idea.

I guess you're suggesting that I can verify that it's not because of the CSV system by doing the "plug swap"? I'm reading through the Cold start issues (http://support.delorean.com/kb/a60/cold-start-issues.aspx) page on the DeLorean site and it mentions some of this.

It says: "The heater should measure about 50 ohms to ground, and the switch connection should measure a dead short (0 ohms) to ground when cold and open (infinite) to ground when hot. NEVER apply a test voltage to the TTS." Doesn't setting the voltmeter to resistance measurements automatically apply a voltage in order to read resistance? If so, how are you supposed to measure the resistance without applying a test voltage?

[vwdmc16]

yeah, non-OE cams. I set the timing back when I finished the rebuild a few years ago but it's a good call out. I should verify that the timing is correct. Any idea what it should be for non-OE cams?


Did the cams come with a set up card? Only real way to change cam timing is to re drill holes in the cam sprockets.

Did it start fine when you first got it back together after the rebuild?

[Bitsyncmaster]

Crap, I was worried about that. I can measure +Duty and/or -Duty on the scope and I chose +Duty because I wasn't sure if it should be high time or low time. Unfortunately, I removed my WOT switch from my car -- it was broken and causing other issues. Can I just ground the WOT pin to enable the WOT mode? Or maybe I need to short the two pins together? That should be an easy way to check.

Yes you would need to connect that signal to get 60% dwell for checking your scope reading. You get 50% at warm up but that won't show any inversion.

[David T]

Whoever supplied the cams usually gives instructions on how to install them and what to set the base timing to. Refer to M:01:04 for the specs for timing advance. The "plug swap" forces the cold start valve open. Useful to troubleshoot hot and cold start problems. Before testing the TTS, try the plug swap. If that gets the motor to start easily then you can check out the TTS and the wiring. The manual warns against putting 12 volts on the TTS. A resistance meter is only going to apply about 1 1/2 volts, that is safe to do. For a better look at the cold start system refer to D:01:10 and D:04:06

[DMC5180]

Most of The high lift cams have base timing set from 16-18 BTDC. But whom ever you bought them from should give you guidance.

[vwdmc16]

Most of The high lift cams have base timing set from 16-18 BTDC. But whom ever you bought them from should give you guidance.

To be clear are you talking about cam timing or ignition timing? 16-18 Btdc sounds like ignition

[spikeygg]

Did the cams come with a set up card? Only real way to change cam timing is to re drill holes in the cam sprockets.

Did it start fine when you first got it back together after the rebuild?

I don't think I have any card for it. In my possession, the car never ran correctly. When I got it, it was running on 4 cylinders and the WOT switch was broken (always on). I hypothesize that the previous mechanic that put it back together didn't realize the WOT switch problem and backed the fuel mixture screw all the way down. I found a bunch of stuff, went through the car and upgraded a bunch of stuff in the process (like the crappy wiring). It runs much better now but there are some things I need to wrap up like this stupid cold-start problem.

I don't want to change the timing of the cams, I guess I'm wondering what the base timing should be on a car with aftermarket cams -- maybe I need the card.

[spikeygg]

I just did the plug swap and it started right up.

So, I think that means the cold start valve is good, right?

After that I tested the pins of the TTS to engine ground and found that one pin was about 30Ω and the other was 0.2Ω -- both of those values sound right. The electrical clip that clips into the TTS sensor is badly damaged, I wonder if that clip isn't making a good contact to those TTS pins...

What else can I check?

[Bitsyncmaster]

I just did the plug swap and it started right up.

So, I think that means the cold start valve is good, right?

After that I tested the pins of the TTS to engine ground and found that one pin was about 30Ω and the other was 0.2Ω -- both of those values sound right. The electrical clip that clips into the TTS sensor is badly damaged, I wonder if that clip isn't making a good contact to those TTS pins...

What else can I check?

There are connections also in the bulkhead connectors. My car had a bad bulkhead connection that made the CSV fail. I would suggest you use an ohmmeter to verify all the connections from the CSV to TTS are good. The bulkhead used a few pins just to join some wiring with a jumper on the back side of the bulkhead. Those are not documented.

[David T]

If it started right up cold with the plug swap it proves;
a) the CSV is good and works
b) for whatever reason the CSV was not operating on it's own.
The next step is to check the wiring and connectors. I have seen the plug to the TTS deformed and incorrectly plugged into the TTS causing it to burn up inside. I have seen the TTS installed with teflon tape effectively preventing it from connecting to ground. I have seen the wire going to the starter either disconnected or connected to the wrong terminal. Let's see what you find. Trace the system out wire by wire.

[spikeygg]

So, I just went out and checked some of the wiring. It looks like the two pins at the sensor plug are shorted together... is that normal? I even pulled the two white bulkhead connectors and they're still shorted together at the TTS connector.

What I mean is that WR (32) is shorted to UB (47). Any ideas where these wires may be shorted?



edit
I found that the CSV has those pins shorted. When I pulled the plug on it, the short went away. I'm guessing that's normal? Seems that the wiring is good and separate from the TTS plug to the bulkhead and to the CSV.
end edit

[Ron]

That sounds normal.

Unplug the TTS. At the Hot Start Relay, jumper the UB wire to the B (ground) wire. If it still starts right up COLD, the TTS or its wiring is bad. Check the TTS socket-plug, WR wire for 12V while cranking, and its UB wire for ground (while the jumper is still in place). If OK, replace the TTS.
Don't forget to remove the jumper or the engine will flood....

[spikeygg]

I'm trying to figure out if my starter is hooked up right to WR. I can see the White/Red wire but I can't quite see how it plugs into the starter and the heavy red cabling is in the way and difficult to move. Googling around for "DeLorean Starter" images result in pictures that don't quite look like my starter. Any idea if this looks correct? Can someone shoot a photo of their starter plugged in? Maybe that WR wire is easily visible in the same spot...

62300

[WHO1DMC]

I'm trying to figure out if my starter is hooked up right to WR. I can see the White/Red wire but I can't quite see how it plugs into the starter and the heavy red cabling is in the way and difficult to move. Googling around for "DeLorean Starter" images result in pictures that don't quite look like my starter. Any idea if this looks correct? Can someone shoot a photo of their starter plugged in? Maybe that WR wire is easily visible in the same spot...

62300


This might help.
http://dmctalk.org/attachment.php?attachmentid=61468&d=1571608950

Dave B.

[Ron]

The WR wire should have 12V on it while cranking, only.
If you follow the steps in my previous post, in order, any problem with the CSV or the wiring for it should be identified.

[spikeygg]

That sounds normal.

Unplug the TTS. At the Hot Start Relay, jumper the UB wire to the B (ground) wire. If it still starts right up COLD, the TTS or its wiring is bad. Check the TTS socket-plug, WR wire for 12V while cranking, and its UB wire for ground (while the jumper is still in place). If OK, replace the TTS.
Don't forget to remove the jumper or the engine will flood....

Ron, I have Dave's solid state hot start relay. I just went out and tried to find a way to jumper UB to B. I don't have male spade connectors available so I pulled the hot start relay out a little and use an alligator clip from the UB to the B and it still wouldn't start. Not sure if using the relay pins is a good idea or not but it didn't seem to make a difference.

[Ron]

Ron, I have Dave's solid state hot start relay. I just went out and tried to find a way to jumper UB to B. I don't have male spade connectors available so I pulled the hot start relay out a little and use an alligator clip from the UB to the B and it still wouldn't start. Not sure if using the relay pins is a good idea or not but it didn't seem to make a difference.Not a good idea usually...Jumpering different wires together at a socked/plug is usually done when disconnected.

The test(s) assumes there are no modifications. The hot start relay and some of its wiring was abandoned by DMC. If Dave's hot start relay requires wires to be added/changed, the test is not reliable.
Otherwise, remove the relay, confirm that it starts COLD with the plug swap test. Then repeat the tests.

Since it started right up when you did the plug swap, we're assuming the CSV is good but it's not being energized. So its WR wire is not bringing 12V to it or its UB wire is not grounding it (the TTS's job). Jumpering UB to B should ground it and if the WR wire has 12V, the CSV will energize and the engine should start cold (as with doing the plug swap). If not, the TTS is probably bad. This can be confirmed by disconnecting the TTS and checking for continuity...The TTS's metal case (ground) should have continuity to its WR and UB terminals when COLD. [When it is HOT (from cranking), the TTS's metal case should have continuity to the WR terminal only).

If in doubt, when the engine is COLD and the starter has not been used for several minutes, put the CSV in a bucket and see if it sprays while cranking.

[spikeygg]

That sounds normal.

Unplug the TTS. At the Hot Start Relay, jumper the UB wire to the B (ground) wire. If it still starts right up COLD, the TTS or its wiring is bad. Check the TTS socket-plug, WR wire for 12V while cranking, and its UB wire for ground (while the jumper is still in place). If OK, replace the TTS.
Don't forget to remove the jumper or the engine will flood....

Ok, I'm back at it now that it's nice outside again. I did the jumper with Dave's solid state relay removed. The car still doesn't start right up. I checked the voltage at the TTS while jumpered and cranking and it hit just over 10V. With the UB not jumpered to ground the TTS only sees about 1V while cranking.

I bought a new TTS from DeLorean assuming it was bad but the new one exhibits the same response as the old one.

[David T]

If you can use a scope you can read a wiring diagram. Go to D:04:06 and check the wiring to the TTS and the CSV and starter. Verify there is nothing plugged into the hot start relay plug by the fuse block. Polarity on the TTS is VERY important. Screw it up and you burn it out (and it only takes a second!). Follow this advice and it should fix the hard cold start problem. Other things to check is vacuum hose routing and pay particular attention to how the distributor vacuum solenoid is connected. If the hoses are reversed it won't work right. Then check timing. There is a good write-up in the how to's to check the vacuum and mechanical advance. You don't have to have a WOT switch but it's good to have. The wiring diagram for the Lambda circuit is D:04:12. The WOT and Thermal switch share the same wire and they ground it to force the circuit to full. Base (initial) timing is ignition timing, not cam timing. As far as I know, ALL cams are installed to the same timing, ie, you line up all of the marks. OEM cams use 13 degrees BTDC. If you use a "hotter" or performance cam they are usually set a few degrees more advanced, say 16 degrees. If you don't know whose cams are in the car and you don't have the documentation you can experiment with the timing to find the right spot. On a hot day you try advancing the timing till you get pinging (detonation) and then back off 2-3 degrees. This is very dependent on the octane of the fuel you use, lower octane means less advance. More advance means more power but also more heat. Before playing with the timing you should get everything working correctly and in good tune, like a clean air filter, fresh spark plugs, etc.

[Ron]

Ok, I'm back at it now that it's nice outside again. I did the jumper with Dave's solid state relay removed. The car still doesn't start right up. I checked the voltage at the TTS while jumpered and cranking and it hit just over 10V. With the UB not jumpered to ground the TTS only sees about 1V while cranking.

I bought a new TTS from DeLorean assuming it was bad but the new one exhibits the same response as the old one.

The requirements in the test are that the WR wire has battery voltage, 12V+, and the UB wire is grounded before assuming the TTS is bad....
But it sounds like you are onto the problem (low voltage on WR wire).

If you checked the voltage with the TTS unplugged (you should), there should not have been a difference when the jumper is in or out.
Repeat the test with the TTS and CSV unplugged. Record the voltages at both plugs when the key is in the start position. They should be the same (~12V+). If not, I'd need to know if your D had the starter relay wiring modification performed to go further (see service bulletin ST-05-2/82).

[spikeygg]

I measured the direct battery voltage after all testing and it was 12.55V. My VIN is 4796 so I think it should already have the TSB applied.

http://dmctalk.org/attachment.php?attachmentid=63290&d=1586707702

63290

What could be the cause of the voltage drop at the CSV and TTS with the HSR-UB jumpered?

I'm looking at the big colorful wiring diagram and with the TTS and CSV disconnected the WR wire seems to only hit the ignition switch, the starter, the starter relay and the hot start relay.

[DMC5180]

I measured the direct battery voltage after all testing and it was 12.55V. My VIN is 4796 so I think it should already have the TSB applied.

http://dmctalk.org/attachment.php?attachmentid=63290&d=1586707702

63290

What could be the cause of the voltage drop at the CSV and TTS with the HSR-UB jumpered?

I'm looking at the big colorful wiring diagram and with the TTS and CSV disconnected the WR wire seems to only hit the ignition switch, the starter, the starter relay and the hot start relay.

Have you done a source voltage check at the start inhibit relay? Pull the relay and ensure all terminals are in place ( none pushed out) trust me it happens. Supply voltage should be socket terminal 30. If thats good. Move to the bulkhead connector. (White 7 way connector) unplug it and test voltage on the pin (key in start position) if thats good. Just the act of disconnecting and reconnecting a couple times can fix a poor connection here. Note: The W/R wire splits in the Engine bay harness side BH connector. These are 2 unique W/R wires. The wire to the CSV has a spiraling (candy cane) Red stripe. The other W/R wire has the typical parallel Red tracer.

[Bitsyncmaster]

I measured the direct battery voltage after all testing and it was 12.55V. My VIN is 4796 so I think it should already have the TSB applied.

http://dmctalk.org/attachment.php?attachmentid=63290&d=1586707702

63290

What could be the cause of the voltage drop at the CSV and TTS with the HSR-UB jumpered?

I'm looking at the big colorful wiring diagram and with the TTS and CSV disconnected the WR wire seems to only hit the ignition switch, the starter, the starter relay and the hot start relay.

Are you jumping the UB wire in the hot start relay socket to the black wire in the hot start relay socket?

The CSV only gets power when the starter is cranking (the white/red wire).

[Ron]

I measured the direct battery voltage after all testing and it was 12.55V. My VIN is 4796 so I think it should already have the TSB applied.

http://dmctalk.org/attachment.php?attachmentid=63290&d=1586707702

63290

What could be the cause of the voltage drop at the CSV and TTS with the HSR-UB jumpered?

I'm looking at the big colorful wiring diagram and with the TTS and CSV disconnected the WR wire seems to only hit the ignition switch, the starter, the starter relay and the hot start relay.
Good job...
Assuming the key is start position and Dave's hot start relay is removed (as directed ;-), your chart shows that the TTS is not grounding the UB wire and that the WR wire, from the starter relay, is not supplying enough voltage to the TTS or CCV (and probably not to the hot start socket, fwiw).

Odd, but it seems like the TTS is bad (or its case is not grounded...) and relay pin 30/51 is not getting 12V from the fan breaker (or maybe a bad relay).

You should have this:

63291

[spikeygg]

Have you done a source voltage check at the start inhibit relay? Pull the relay and ensure all terminals are in place ( none pushed out) trust me it happens. Supply voltage should be socket terminal 30. If thats good. Move to the bulkhead connector. (White 7 way connector) unplug it and test voltage on the pin (key in start position) if thats good. Just the act of disconnecting and reconnecting a couple times can fix a poor connection here. Note: The W/R wire splits in the Engine bay harness side BH connector. These are 2 unique W/R wires. The wire to the CSV has a spiraling (candy cane) Red stripe. The other W/R wire has the typical parallel Red tracer.

I just pulled the white 7-way bulkhead connector and with the start inhibit relay in place, I see 12.8V at pin 32 while cranking. I see 13V at the brown wire going to the start inhibit relay. As well, none of the pins appear to be pushed through.

[spikeygg]

Are you jumping the UB wire in the hot start relay socket to the black wire in the hot start relay socket?

The CSV only gets power when the starter is cranking (the white/red wire).

Yes, jumping the UB to black in hot start relay socket with the solid state relay removed.

http://dmctalk.org/attachment.php?attachmentid=63293&d=1586729983

63293

[spikeygg]

Good job...
Assuming the key is start position and Dave's hot start relay is removed (as directed ;-), your chart shows that the TTS is not grounding the UB wire and that the WR wire, from the starter relay, is not supplying enough voltage to the TTS or CCV (and probably not to the hot start socket, fwiw).

Odd, but it seems like the TTS is bad (or its case is not grounded...) and relay pin 30/51 is not getting 12V from the fan breaker (or maybe a bad relay).

You should have this:

63291

This is a photo of the back side of my start inhibit relay. I think I can see the modification, one of the old wires was cut and a RW wire was run in its place.

http://dmctalk.org/attachment.php?attachmentid=63292&d=1586729394

63292