GREMLIN CONTINUES TO BE PRESENT MAKING DRIVING UNSAFE

[Ttype6]

Just yesterday I was finally able to pull the glove box down and mess around with the pink wire from the steering column to just above the ECM as some suggested I do. I did not have time to go to the purple wire or any other wires or start removing anything and shifting things around but will do more of this in coming days and weeks outside the GS Nationals as time permits. I moved it back and forth, pulled on it, did everything I could think of whiile the car was idling in the driveway and nothing happened as of yet.

Thanks for the time on your post. I will be working to have the PL with me every time and what I may try to do if I have not found the smoking gun is turn it one when I brake, turn left, turn right and see if it shows up. If not, I will just have to keep it ready for when it takes place and hit the record button asap once it happens and I am hopefully not in a lot of traffic and can get off the road. The ONLY times it has ever happened is when I am braking hard or fairly hard or turning and speed is decreasing. I have yet to see it take place upon acceleration or just constant speed, cruise control on, etc...its always more in a declining spead situation and can be at 20mph or 50mph and in various weather conditions and various amounts of time on the road from 10 minutes to maybe 45 minutes.

When you think back on it happening while turning, was it consistently a left or right turn or was it in both directions? Does the car sit lower than the average GN? Do you have an aftermarket adjustable chip?

 

[TexasT]

Don't discount any of these scenarios above. Check on all of them. Mine was a corroded full pump harness in the tank that lost power at the fuel pump. Those little pins aren't much to begin with and when corrosion gets going it makes for a bad day. No fun when it dies cruising down the highway.
Lots of things can and will go wrong in vehicles this old. Being good with a meter and knowing the wiring and where it goes and what it does is real handy.

 

[Hunter Dog]

I am original owner of this garage kept 90% original, stock show car that has 116,000 miles on it. I have a Powerlogger hooked up but no other after market gages. There is no chance of any water getting inside the car or ECM. It seems like it happens more on a left turn or breaking hard with no turn. I am not sure I can remember it quiting on a right hand turn but it may have. It is so seldom (which is good it is also bad) it is hard to find a pattern. It could happen in a week, month or not for another year. I did hook up Powerlogger today and took it for a "spirited" 20 minute drive. I made some turns, hit the brakes hard a few times at various speed and of course the car range great and it did not quit on me. I am going to mess around with more of the wires and go a bit further down into the ECM area and above it and deeper and behind the glove box.

 

[GNVYUS 1]

You'll want to log fuel pressure if possible but due to the nature of your issue keep logging and maybe it'll catch a sync error or something to help narrow this down for you.

Usually the coil pack gets hot and can cause issue or a random wire in that main connector to the module so try this....

Car running, start gently tugging on module wires in the connector and see what happens, might be a loose pin etc.

I think Bob Bailey or some other GN guru on here has a whole detailed way of checking this better than, tug on wire. Haha

 

[Dan SS2471]

Do you modify any chip settings via PL? If so, have you checked to see if the settings are still set after this happens? IE - did the ECM lose power.

 

[SCOOBY DOO]

There is no chance of any water getting inside the car or ECM

Have you disconnected the orange power wire by the battery for the ECM and then disconnected the ECM and checked all the pins.

 

[turbojay]

For years, I had a similar issue with my GN, where it would just die driving down the road. It would start back up after few minutes. This would happen 2-3 times a year. My issue was two fold, first the bigger plug that goes into the ECM had a loose wire in it. I figured this out by wiggling every wire that was in the plug and touching one of them made the car shudder and die. But the car still would die while driving so next I just replaced the ECM box with one from a super low mileage GN and the issue went away permanently. You will need to go through all of the scenarios others have posted, I'm certain your issue is one of them. Good luck.

 

[SCOOBY DOO]

I've seen ECM's do some really silly shit over the years. I always kept two spares.

 

[Hunter Dog]

Thanks to all for the well thought out replies, much appreciated. I really want to find this issue soon as the car show season has begun and I don't want to keep looking over my shoulder every time I get it out and have to drive in the right lane.

Few follow ups to your comments; We have original ECM and have not modified it other than installing the Powerlogger. I have not tried to alter or play around with any chip through use of the Powerlogger. Since my original post on this topic I have not had time to pull the ECM or get down and dirty with all the wires to it yet, but will soon, probably later this month after the GS Nats. I will be there but not with this particular vehicle.

Thanks again fellow GN owners !

 

[Ttype6]

I am original owner of this garage kept 90% original, stock show car that has 116,000 miles on it. I have a Powerlogger hooked up but no other after market gages. There is no chance of any water getting inside the car or ECM. It seems like it happens more on a left turn or breaking hard with no turn. I am not sure I can remember it quiting on a right hand turn but it may have. It is so seldom (which is good it is also bad) it is hard to find a pattern. It could happen in a week, month or not for another year. I did hook up Powerlogger today and took it for a "spirited" 20 minute drive. I made some turns, hit the brakes hard a few times at various speed and of course the car range great and it did not quit on me. I am going to mess around with more of the wires and go a bit further down into the ECM area and above it and deeper and behind the glove box.

Do you have an aftermarket chip?

 

[jskarateka]

X2 what MikeS posted. Next time you have it running bump the orange fusible link wire coming off the battery terminal that powers the ECM and see if it dies out. They develop an internal connection break from bouncing for 37 years (ask me how I know).

 

[Hunter Dog]

This afternoon I checked the fusible link coming off battery, orange wire to a red wire, it was good and tight. Messed around with it while car was running, nothing happened, saw no damage or anything. I am going to check wires near the starter next, then start messing around the area near the ECM, behind glove box and see what happens. Thanks again for the input. I will continue to test things and post results.

 

[GNVYUS 1]

Wiggle coil module plug and wires in that too as part of your next tests.

 

[SCOOBY DOO]

If memory serves, a member had your problem. The large wire loom behind the engine had got stuck on a screw from the firewall and it had penetrated the loom and gotten into the wires.

 

[Hunter Dog]

With car running I checked the wires going into the coil pack and nothing changed after some movement in all directions.
I lowered glove box and took off the grey kick panel and removed the ECM which is connected to the Powerlogger. When I was doing this as the car was running I noticed the car did stumble. It did not quit all together like when the issue occurs. I tapped on the ECM and it did the same thing, did not cause car to quit but it stumbled. I am not sure if I am on to somethere here or not????

 

[Bescurred]

I'd find another ECM if its stumbling when you're messing with it. I had a similar issue and it was a cracked harmonic balancer.

 

[GNVYUS 1]

You can keep going deeper here and really on point the issue or...

There's plenty of spare ECMs out there for sale, time to try a different one and see how things go.

You'll need to recreate this again though, car running, tap on stock ECM, if it stumbles pull ECM, swap chip into ECM2 and do exact same thing and see what you get.

 

[gsgns4me]

You can keep going deeper here and really on point the issue or...

There's plenty of spare ECMs out there for sale, time to try a different one and see how things go.

You'll need to recreate this again though, car running, tap on stock ECM, if it stumbles pull ECM, swap chip into ECM2 and do exact same thing and see what you get.

That's how the techs at the dealerships checked for intermittent stalling issues when these cars were still under warranty. If no other obvious things were found to be the cause of trouble or they had trouble duplicating the customer's stalling complaint, just tap the ECM a few times with their hand and see what happens. Stumble, stalling and a new ECM was installed.