Car randomly shuts down
#31
#32
So did I forget to give a key update? Roger was kind enough to send me a new ignition switch, which I installed...and it did not fix the problem. However I still think making the telltale circuit will be useful. It certainly behaves like something in that circuit is losing contact, so while it may not be the switch itself, it could still be in the harness somewhere, etc.
#35
So did I forget to give a key update? Roger was kind enough to send me a new ignition switch, which I installed...and it did not fix the problem. However I still think making the telltale circuit will be useful. It certainly behaves like something in that circuit is losing contact, so while it may not be the switch itself, it could still be in the harness somewhere, etc.
I've made a couple sets of test lights to try to test intermittent problems (especially this particular problem) without success, but it is certainly worth a try...you never know, for sure, until you find it.
For the first few cars I saw with this issue, I bet I spent 40 hours figuring it out.
......Now, after replacing relays, I cut right to the "90% of the time" issue.
And I've got a few stories to tell about clients with this exact problem....none of which made me very happy.
Last edited by GregBBRD; 10-17-2020 at 02:22 AM.
#36
I would suggest that you disconnect the battery, remove the rt parcel tray,
drop the CE panel down and inspect the rear of the CE panel for melted wires or connectors being pushed out of the relay.
Next put deoxit on all the connections for the fuses and the relays,
and service the ground wire mounting points above the panel
drop the CE panel down and inspect the rear of the CE panel for melted wires or connectors being pushed out of the relay.
Next put deoxit on all the connections for the fuses and the relays,
and service the ground wire mounting points above the panel
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Jason89s4 (11-01-2020)
#38
I really thought that was it! Any particular relay that you found the most likely culprit? I did replace x-bus, fuel pump, LH and EZF relays.
Anything is possible, although the ignition switch was a tiny percentage solution...really tiny.
I've made a couple sets of test lights to try to test intermittent problems (especially this particular problem) without success, but it is certainly worth a try...you never know, for sure, until you find it.
For the first few cars I saw with this issue, I bet I spent 40 hours figuring it out.
......Now, after replacing relays, I cut right to the "90% of the time" issue.
And I've got a few stories to tell about clients with this exact problem....none of which made me very happy.
I've made a couple sets of test lights to try to test intermittent problems (especially this particular problem) without success, but it is certainly worth a try...you never know, for sure, until you find it.
For the first few cars I saw with this issue, I bet I spent 40 hours figuring it out.
......Now, after replacing relays, I cut right to the "90% of the time" issue.
And I've got a few stories to tell about clients with this exact problem....none of which made me very happy.
#39
This sounds like a great idea, and is my goal for the day.
I would suggest that you disconnect the battery, remove the rt parcel tray,
drop the CE panel down and inspect the rear of the CE panel for melted wires or connectors being pushed out of the relay.
Next put deoxit on all the connections for the fuses and the relays,
and service the ground wire mounting points above the panel
drop the CE panel down and inspect the rear of the CE panel for melted wires or connectors being pushed out of the relay.
Next put deoxit on all the connections for the fuses and the relays,
and service the ground wire mounting points above the panel
#40
CE panel is out. Unfortunately, no clear smoking gun. I'm not done going through it, I haven't pulled relays or fuses, but all the pins look to be in place, nothing really looks discolored or melted. In the pic of all the wires it does look a bit like one side is lighter, but that's because I had a light shining on that side.
I did notice one concerning thing...I was getting some water drips from the right side of the recirculating air box flap area. I thought maybe it was dripping down on the CE panel and causing corrosion, but the back of the panel wasn't wet and doesn't appear corroded so far. I've never noticed water in the passenger floor or anything either. It looks like maybe it was dripping behind the right side of the CE panel. Still, a concern that I need to address.
I did notice one concerning thing...I was getting some water drips from the right side of the recirculating air box flap area. I thought maybe it was dripping down on the CE panel and causing corrosion, but the back of the panel wasn't wet and doesn't appear corroded so far. I've never noticed water in the passenger floor or anything either. It looks like maybe it was dripping behind the right side of the CE panel. Still, a concern that I need to address.
#41
Since I "get" to see this stuff day in and day out, I'm betting I've fixed 25 cars with this same symptom.....and probably 90% of the time, it's the same thing.
In fact, of all the stuff that is listed above, other than relays (which is always the first step), I don't ever go to second.
If the car just "signs off", everything fuel related is immediately eliminated.....fuel starvation occurs over several seconds of poor running.
There's a very limited amount of things that will cause instant "shut off".
Crank trigger can do it....but pretty rare.
Certainly disconnecting the LH or EZK will do this....but once the relays are replaced, that's pretty rare.
Bad LH or EZK unit? Anything is possible, but I've never seem a car with either one of these units do this.
I guess ignition switch could do this....not very common in a 928 (but really common in a 924.)
Keep thinking, guys!
In fact, of all the stuff that is listed above, other than relays (which is always the first step), I don't ever go to second.
If the car just "signs off", everything fuel related is immediately eliminated.....fuel starvation occurs over several seconds of poor running.
There's a very limited amount of things that will cause instant "shut off".
Crank trigger can do it....but pretty rare.
Certainly disconnecting the LH or EZK will do this....but once the relays are replaced, that's pretty rare.
Bad LH or EZK unit? Anything is possible, but I've never seem a car with either one of these units do this.
I guess ignition switch could do this....not very common in a 928 (but really common in a 924.)
Keep thinking, guys!
#43
For what it's worth, I pulled all the fuses and relays, did the DeOxit thing on all the contacts, cleaned up the grounds behind the CE although they appeared fine, etc. Put everything back, no change. There was no water corrosion or anything of that nature, so whatever dripped down, must not have actually contacted the CE panel.
I did find a few unrelated dodgy things. The HVAC blower relay socket was a bit discolored, and the fuse looked partially melted, as did the plastic around the fuse. However, the fuse itself was not blown. That seems odd. I replaced the fuse, if for some reason that old fuse was withstanding more than it should, I will know soon. I also had a blown condenser fan controller fuse (not the one for the fuse itself). I thought my condenser fan was working, so that's also weird. Finally, the wiper delay relay and the one next to it (intensive washer maybe) seemed to be swapped, and one of them (I think the washer one) was not the part number it was supposed to be. Yet, my wipers work fine. Maybe they're interchangeable? I have no idea if my intensive washer system works, just thought it was weird.
But none of this had anything to do with the problem at hand, which, sadly, remains a problem. I only got some of the parts to make the telltale circuit today, the rest are now supposed to arrive Tuesday, so I suppose that's the next step. I thought about pulling the LH and EZF to see if I could see anything wrong, but that seems a little pointless right now. Even if one of them is at fault, I doubt I would be able to tell visually.
I did find a few unrelated dodgy things. The HVAC blower relay socket was a bit discolored, and the fuse looked partially melted, as did the plastic around the fuse. However, the fuse itself was not blown. That seems odd. I replaced the fuse, if for some reason that old fuse was withstanding more than it should, I will know soon. I also had a blown condenser fan controller fuse (not the one for the fuse itself). I thought my condenser fan was working, so that's also weird. Finally, the wiper delay relay and the one next to it (intensive washer maybe) seemed to be swapped, and one of them (I think the washer one) was not the part number it was supposed to be. Yet, my wipers work fine. Maybe they're interchangeable? I have no idea if my intensive washer system works, just thought it was weird.
But none of this had anything to do with the problem at hand, which, sadly, remains a problem. I only got some of the parts to make the telltale circuit today, the rest are now supposed to arrive Tuesday, so I suppose that's the next step. I thought about pulling the LH and EZF to see if I could see anything wrong, but that seems a little pointless right now. Even if one of them is at fault, I doubt I would be able to tell visually.
#44
I took a new video. I guess it's pretty much the same as the last one but looking closely at the tach, it definitely seems to me that the car shuts off, then the tach drops. Which would SEEM to imply that it's not the CPS. But, maybe I'm wrong. I was also going to ask about some fairly subtle "dips" in RPM, prior to the actual cutoff, wondering if they might be related, but they're so subtle I can't even detect them in the video so maybe that's just my imagination.
The cutoff is right around 50 seconds.
Dashboard video
Sadly, I have not been able to get a video of the car moving when it happens, or even me holding the revs higher.
The cutoff is right around 50 seconds.
Dashboard video
Sadly, I have not been able to get a video of the car moving when it happens, or even me holding the revs higher.
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Jason89s4 (11-01-2020)