1990 6 speed shuts itself down
Thread Starter
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
1990 6 speed shuts itself down
As title states 1990 6 speed vert.
Appears to have had some decent mods/work over the years, but this failure has me stumped at the moment.
No codes both ECM or CCM (CCM had a couple history that I cleared but have not returned).
Car starts & runs fine, drives fine. But turn on the AC and it is like you turned the key off.
Fuel pressure is up & holding, injectors have been upgraded in the past. My laptop scans show IAC & TPS pretty close to spec and nothing else is glaring at me?
I'm about to pull the ECC head & pull it apart.
Some threads I've researched have suggested its just the ECM failing but I hate to throw a $100 part at it without knowing.
Your thoughts?
Appears to have had some decent mods/work over the years, but this failure has me stumped at the moment.
No codes both ECM or CCM (CCM had a couple history that I cleared but have not returned).
Car starts & runs fine, drives fine. But turn on the AC and it is like you turned the key off.
Fuel pressure is up & holding, injectors have been upgraded in the past. My laptop scans show IAC & TPS pretty close to spec and nothing else is glaring at me?
I'm about to pull the ECC head & pull it apart.
Some threads I've researched have suggested its just the ECM failing but I hate to throw a $100 part at it without knowing.
Your thoughts?
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Is the car STALLING? Or Shutting off?
If it's shutting off, I'd wire a test light to the pink dist wire, see if power goes away when you turn AC on...then I'd trace the ign circuit back to find the problem.
If it's shutting off, I'd wire a test light to the pink dist wire, see if power goes away when you turn AC on...then I'd trace the ign circuit back to find the problem.
Race Director
Joined: Sep 2001
Posts: 14,673
Likes: 750
From: NEwhere Ohio
Had a bizarre problem on my modd 93 supecharged 6spd car once...when youd get on it hard, and itd hook in first gear brutal acceleration on drag radials....the car would suddenly die for a second until th g forces settle down and then Come back to life. Everything including digital dash would blank out. It was almost like a main battery cable was loose or something.
I spent 6 weeks unsuccesfully rewiring all chassis ground points in the car. My battery is relocated btw.
It turned out that my ecm ostrich, plugged into the chip socket, had wiggled loose -likely as a result of increased engine vibrations thru my solid motor mounts....
I spent 6 weeks unsuccesfully rewiring all chassis ground points in the car. My battery is relocated btw.
It turned out that my ecm ostrich, plugged into the chip socket, had wiggled loose -likely as a result of increased engine vibrations thru my solid motor mounts....
Thread Starter
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
I will give this a shot this afternoon...
Yes, it is "Shutting off", not just stalling from load/low RPM...
This happens while just sitting still in the shop so no vibration/movement required to cause it.
This AM while I had the dash apart I was tracking down failed Bose, bad control box under right dash. Had a spare to test after confirming diagnostics from FSM. Time to pack it & all the amps up for a trip to Dr Dons.
Yes, it is "Shutting off", not just stalling from load/low RPM...
This happens while just sitting still in the shop so no vibration/movement required to cause it.
This AM while I had the dash apart I was tracking down failed Bose, bad control box under right dash. Had a spare to test after confirming diagnostics from FSM. Time to pack it & all the amps up for a trip to Dr Dons.
Race Director
Joined: Sep 2001
Posts: 14,673
Likes: 750
From: NEwhere Ohio
I will give this a shot this afternoon...
Yes, it is "Shutting off", not just stalling from load/low RPM...
This happens while just sitting still in the shop so no vibration/movement required to cause it.
This AM while I had the dash apart I was tracking down failed Bose, bad control box under right dash. Had a spare to test after confirming diagnostics from FSM. Time to pack it & all the amps up for a trip to Dr Dons.
Yes, it is "Shutting off", not just stalling from load/low RPM...
This happens while just sitting still in the shop so no vibration/movement required to cause it.
This AM while I had the dash apart I was tracking down failed Bose, bad control box under right dash. Had a spare to test after confirming diagnostics from FSM. Time to pack it & all the amps up for a trip to Dr Dons.
You would think it would just blow the fuse if their was a short or something.
Also. I did not have good experiences with doctor dons. Not only did i have to send stuff to then 2x or 3x to fix the problem, but they are also charging a corvette tax. The work they do claim they do (if its successful) can be done for much less cost. Im sorry i dont have the names of other shops, but other people will do it cheaper
Thread Starter
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
No, Bose is unrelated (although I haven't done a run test since finding it).
That doesn't sound like the Dr Don's that I've used in the past. The rebuild he did on my personal car has been perfect for years.
That doesn't sound like the Dr Don's that I've used in the past. The rebuild he did on my personal car has been perfect for years.
Let me understand this....you are thinking your BOSE radio is what is causing this shutdown????
You would think it would just blow the fuse if their was a short or something.
Also. I did not have good experiences with doctor dons. Not only did i have to send stuff to then 2x or 3x to fix the problem, but they are also charging a corvette tax. The work they do claim they do (if its successful) can be done for much less cost. Im sorry i dont have the names of other shops, but other people will do it cheaper
You would think it would just blow the fuse if their was a short or something.
Also. I did not have good experiences with doctor dons. Not only did i have to send stuff to then 2x or 3x to fix the problem, but they are also charging a corvette tax. The work they do claim they do (if its successful) can be done for much less cost. Im sorry i dont have the names of other shops, but other people will do it cheaper
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Thread Starter
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
A quick update on this car:
A reman. ECM solved the engine shut off when AC turned on. BTW, other modes of AC head that do NOT turn on the compressor did NOT cause this issue.
I have unhooked & checked all wiring between the AC head, AC programmer & ECM to confirm no shorts or opens before finally installing the new ECM...
Stereo which the tuner box had failed is on its way to Dr. Dons (head/tuner & 4 amps)
Dash, out & 300K resister installed in the tach circuit brought the tack back on line. It was pegged at start up & staying there. Factory resister was toast, cut the legs & soldered in new resister from Digikey.
DIC and CCM are now also back on line & working correctly. Buttons were sending mixed signals & range would show up no matter what button you pushed.
I also had checked all system grounds for AC, ECM, Stereo, CCM and although a few looked suspect, cleaning & re-tighten had no effect on the shut down issue.
Thanks for those who chimed in & also the forum in general on the Tach repair... an easy fix.
A reman. ECM solved the engine shut off when AC turned on. BTW, other modes of AC head that do NOT turn on the compressor did NOT cause this issue.
I have unhooked & checked all wiring between the AC head, AC programmer & ECM to confirm no shorts or opens before finally installing the new ECM...
Stereo which the tuner box had failed is on its way to Dr. Dons (head/tuner & 4 amps)
Dash, out & 300K resister installed in the tach circuit brought the tack back on line. It was pegged at start up & staying there. Factory resister was toast, cut the legs & soldered in new resister from Digikey.
DIC and CCM are now also back on line & working correctly. Buttons were sending mixed signals & range would show up no matter what button you pushed.
I also had checked all system grounds for AC, ECM, Stereo, CCM and although a few looked suspect, cleaning & re-tighten had no effect on the shut down issue.
Thanks for those who chimed in & also the forum in general on the Tach repair... an easy fix.