GREMLINS! Let's hear your symptoms, diagnosis, and what you found to fix

[Toby_Goodmk]

I thought about doing this awhile back and forgot to post about it upon one of my many "gremlins" that appear from time to time. I thought it would be fun, and or maybe beneficial for when a gremlin pops up, what was the symptom, the diagnosis and solution. I bet there are many that may be able to use a search function to benefit from a similar issue.

Symptom: Today I get into my car to drive to work. All starts up well, pull out of the garage, AF goes rich and eventually stalls out. As the ATS warms up the symptoms are changing. The car quits immediately as the day goes on and the temps outside and in the intake warm. Symptoms go from rich condition to immediate stall. Car immediately stalls turning the wheel. Getting MAP codes, 02 sensor codes, cam sync codes.

Diagnosis.
1. Take a data log to see on screen WTF.
2. Text Cal since he is superman.
3. Send log to Cal
4. Recommended to look at MAP circuit.
5. Replaced MAP sensor, symptoms are similar, and a little better, but immediate stall.
6. Drive car at lunch, car immediately quits when turning to the left
7. Look at wiring under dash that supports power to the ECU, all checks out ok.
8. Coil pack grounds check out ok
9. Coil pack hot wire bypass, checks out ok (by passed the hot wire installed directly with factory wiring)
10. Examine wiring at ECU to make sure any connections are ok at FAST ECU, all checks out ok.
11. Test fuel pump relay at fender all checks out ok, tap tap....all ok.
12. Examine wiring from MAP green wire to PAC ALKY control box to FAST MAP circuit. Pull wiring while car is operating, immediate stall. Bingo.

So it appears the wiring going into the pac box for the alky system has come loose and will need reconnected. Better yet, will be soldered. Every time I turned a certain way the wire under the dash would get pulled and make an open in the MAP circuit causing the car to stall.

Action:

Don't use butt connectors.

 

[mikes86ttop]

Seems like the best way is to check, double check, and then check a couple more times and maybe all the stars will align with the turbo gods and be A ok...Mike

 

[DarthBuick]

Mine was running very rich at idle and lean WOT. I moved my fuel pressure gauge to wiper area and made a couple of runs.
Fuel pressure did not rise with boost.
Checked vacuum lines to see if tight and they were.
Pulled vacuum line off FPR to check line off pressure and gas came out the FPR vacuum line.
Ordered new FPR diaphragm kit from Kirbans and all is well now.

 

[John Larkin]

1.Mine would run and idle great until I drove about 3 miles, then it would randomly die. I would pull over, restart and all was good. Turned out the crank bolt needed to be retorqued as it would walk out and the crank sensor would lose signal.
2. Started popping and stuttering at 10psi boost. Found one bad plug wire.
3. Driving down the highway, everything was wonderful for a while until it would sputter at cruise almost violently and had to limp home. Stock MAF went bad.
4. Kept blowing the cig/clk fuse. Dome light socket was somehow arcing. WTF? But that's what it was.
5. Similar to above, same thing with the stock cigarette lighter socket. For that I bought a replacement socket and ran a 10 gauge fused wire to the fuse block. No more problems.

 

[Frederickdav]

Purchased my 87 T 4 years ago Sept. When I bought it the idle was terrible but figured it could be fixed. Tried all sorts of things even reading the stack of paper work that came with the car. Previous owner spent big$ trying to fix poor idle. One day a few weeks ago I woke up with a thought in my senile brain, change the chip! So, I ordered a 5.7 from Turbo Tweak. Got the chip a week later and installed it. It was like the car suddenly learned how to run! It starts, doesn't stall at every red light, and run smoooooooth! It even shifts smoother! The car used to squeak the tires when my foot was heavy and it shifted into 2nd. Now it just nicely shifts and keeps going faster and faster.