Difficult Ignition Cutout Problem

[jeff1234]

Cordes, would it be accurate to say that the event never happens at idle? J2 feeds power to the map solenoid array, the diagnostic plug and the ac/heater. Iknow that you realize this but where I'm going is... have you noticed a loss of power anywhere else during the event. I'm thinking it's a loss of power at the supply rather than an isolated circuit problem of some kind. Just my two cents.

[cordes]

Cordes, would it be accurate to say that the event never happens at idle? J2 feeds power to the map solenoid array, the diagnostic plug and the ac/heater. Iknow that you realize this but where I'm going is... have you noticed a loss of power anywhere else during the event. I'm thinking it's a loss of power at the supply rather than an isolated circuit problem of some kind. Just my two cents.

That is a great suggestion. I have not noticed a loss of power at the heater control panel, but the problem can be so brief, that I don't think I would notice. That said, I have back probed the J2 circuit at the bulkhead connector, and did not notice a drop in power while logging it.

At this point, I'm thinking any wiring problem must be inside the car, and the only mechanical components which could be causing it are an injector or the coolant temp sensor (though I think I may have actually replaced it at one time).

Thanks again for the suggestions.

[cordes]

I pulled the injectors out of CSX #42 and installed them in the Lancer. They are 83lb injectors. I made a cal for them, and the car runs well. I drove it close to 30 miles and it only cut out on me twice. Once was a pretty hard cut out. It was probably half of a second where the tach sat at 0. The second time it was a minor drop out of the tach before it came back. I'm really not sure how I'm going to get this figured out with such a random and short lived cut out problem. I guess I'll start working on the wiring in the car, as I've replaced literally everything else at least once.

ETA: I checked all of my grounds, and there is less than 7mV between the battery - and any of them with the exception of the alternator case, which was about 35mV. I assume that's due to the noise from the alt, but I don't know.

I then began to inspect the Z1 circuit under the dash. I disturbed where the driver's side connector is, and gave the best visual inspection that I could. I can't see any problems with anything. Another test drive and it only cut out once in about 10-15 miles.

It's getting harder to diagnose this problem, as the issue happens less often.

[chromguy]

Hi Brian,
I believe you switched coil but mine was SO hot I could not touch it. Switching coils is my next test

[cordes]

I've swapped the coil many times, but the one in the car now was a mystery coil which was lying around. I'll take the one out of the CSX since it's down for a bit with a brake issue. #497 runs like a top, so if it still cuts out, it's certainly not the coil.

[jpcturbo]

I feel you already addressed this, I couldn't find it with a search in this thread, but what about the ignition switch in the steering column? If it had an intermittent connection internally, could it cause these symptoms?

[cordes]

I feel you already addressed this, I couldn't find it with a search in this thread, but what about the ignition switch in the steering column? If it had an intermittent connection internally, could it cause these symptoms?

I have changed it once. I did put the J2 circuit on the scope and I don't believe it dropped out.

At this point, I'm thinking I may replace the pins on the LM which are currently in there. I looked yesterday, and also thought that the dist is very much clocked too far with the way the timing was setup on this It looks like one of the plug wires is super close to the head as a result. Could that be throwing things off? We'll find out...

[c2xejk]

Not to be too much of a broken record, but... Have you checked fuel pressure, have you captured a scope trace when the problem is occurring? A scope trace of fuel injector pulse, spark (primary or secondary), MAP and TPS would be a good choice...

I would recommend you stop making changes to the car until you can get to the root of the problem...

[cordes]

Not to be too much of a broken record, but... Have you checked fuel pressure, have you captured a scope trace when the problem is occurring? A scope trace of fuel injector pulse, spark (primary or secondary), MAP and TPS would be a good choice...

I would recommend you stop making changes to the car until you can get to the root of the problem...

The fuel pressure seems fine, (ETA: I have a gauge on my regulator which appears functional) but I don't have a gauge on the windshield when I'm driving. Should I hook up to a gauge to the 1/8" NPT port and tape it to the windshield?



I have posted a video showing the scope when it happens.

Ch1 Ignition on J2 feed
Ch2 Tach feed
Ch3 Ign reference sensor signal
Ch4 Fuel Injector Sync Pickup Signal



I have some attenuators now, so I should be able to do the injector voltage, primary or secondary spark, etc. I'm working on the minivan for the next couple of days, but I'll try to get right back on the Lancer when I'm done.

[c2xejk]

When during the recording does the problem happen? Not sure if the recording has enough resolution to see an issue.

I would definitely tape the fuel pressure gauge to the windshield so you can see it when the problem happens..

[cordes]

When during the recording does the problem happen? Not sure if the recording has enough resolution to see an issue.

I would definitely tape the fuel pressure gauge to the windshield so you can see it when the problem happens..

It happens shortly before the video ends. I rewatched it when I posted it yesterday, and it almost looked like the J2 feed dropped out at about 1:23 in the video.

[c2xejk]

Throughout the video there were some short blips in the Ignition feed... do you have a higher res picture of that section? I don't see that narrow pulse causing a problem...

If you think ignition drop out is the cause, you could get a fairly large capacitor and back-probe one lead and hooking the other lead to the negative term...That should smooth out the drop outs. Then you can figure out what is causing the drop out.

[cordes]

Throughout the video there were some short blips in the Ignition feed... do you have a higher res picture of that section? I don't see that narrow pulse causing a problem...

If you think ignition drop out is the cause, you could get a fairly large capacitor and back-probe one lead and hooking the other lead to the negative term...That should smooth out the drop outs. Then you can figure out what is causing the drop out.

Thanks again for the feedback. I'm going to do some extensive testing soon. I'll see if I can get you more detailed views of things.

I did reset the cam timing today so the dist is in a more traditional position. It made no difference, however this car is really running like a champ when it is not cutting out.

[cordes]

TurboDave came over the other day and we gave everything a once over. The car idled and revved flawlessly for about a half hour. He had a LoadPro with him and we used it to determine that the wiring back to the fuel pump and the fuel pump ground are both great. That was a huge time saver.

We poured over the wiring diagrams, and noticed a splice off of the J2 wire at the bulkhead connector in the car. It feeds the #8 fuse on the pass side of the car. It seems to feed power to the inst. cluster, the message center, chimes, headlight delay relay, electronic voice alert, and cruise.

I pulled that fuse today and went for a drive. I went 12.5 miles and stopped to do some photo work. The car ran fine that whole distance, which would be ultra rare before. I decided to take a very long way home, making the total distance about 60mi on the day. The car cut out a couple times, but not harshly as before. It was always at very low load. I'm inclined to think that it might be due to the fact that I have nothing hooked up with the exception of things to not make it go into limp mode. Seems like the fuel pressure gauge on the windshield that has been suggested so many times would have been prudent today... I'll try to cobble something up to make that happen safely.

I think I'll reinstall all of the LM pins, and perhaps replace the ones in the LM currently. Then I'll reinstall fuse #8, and test it, followed by another drive with it removed. If it's anything on that fuse, I would think that it would be evident rather quickly.

Furthermore, I ordered a LoadPro of my own which will be here in a couple days. Frankly, I would convert to Microquirt already, but the idea that this could be caused by something on the J2 circuit under the dash leads me to believe that it may not be prudent, as it could interfere with whatever else I may power off of the J2 wire.

[cordes]

Alright... I just spent some quality time with the Loadpro hooked up to my multimeter. I unplugged everything and fed 12v from the battery to the individual circuits. I didn't experience a voltage drop of more than .1v with the exception of one circuit which was .15v drop. I'm not very concerned about that.

I tested each socket on the PM, and also everything for both HEP connectors. Anything which was plugged in currently (no pun intended) was tested. I noted no problems anywhere.

One thing which did surprise me was the way that some of the terminals at the LM connector allowed the fatter Loadpro pin to slide right in, while others didn't allow it in at all.

I have more than enough new LM pins to put new terminals on each wire. Time to give that a try I guess...


ETA: The delay module on the relay block in the car was very hot, so I removed it. The J2 wire sections throughout the dash all tested fine with the Loadpro, so I put the inst cluster and headlight switch back in the dash, but most everything is still hanging everywhere.

[cordes]

Well, close to 70 more miles on the car, and nothing but solid running. Perhaps the new LM pins were all that was needed to get me over the top. I'll say that the difference between the insertion force of the connectors now vs. with the original ones is very significant.

While I'm hesitant to close this chapter, lest the intermittent problem rear its head again upon first startup tomorrow, I'll declare victory. Tomorrow I'll get everything put back together and hop all is well, though with the testing today, I have no reason to see why it shouldn't.

Thanks to everyone in this thread who helped out. There were obviously a ton of little things wrong with the car, and each step made it run a little better. Without you guys, there is no doubt that this car would have been parted out at the least. I've been impressed with this group, and the SDAC members from day one, and things like this are certainly a huge reason why. Thanks again everyone!

[chromguy]

I wish you all the best of luck, SIR
which part number did you used for the LM pins?

[Shadow]

Dang, fingers x’d for you Bro! 😀

Would be awesome to put this all in the rear view

[cordes]

I wish you all the best of luck, SIR
which part number did you used for the LM pins?

I'll see if I can look it up. I'll say that I had to use my Delphi crimper tool once for the wire crimp piece, and once for the insulation crimp part. It was tedious, but produced excellent results. My normal crimper would have been too wide to avoid bending over the two front tangs.

[jpcturbo]

You may now have the overall best running turbo-mopar since they were new. Congrats! You seemed to have occurred a failure every ~20 miles, so at 100 miles of solid running you are at >5x the error interval and thus good enough for most quality assurance programs, lol. I too am interested in the Delphi crimper tool PN as I've had issues with LM pins in the past.

Jeff