Howdy yall, I am working on a 85gt stock , Im having trouble running right, this car has not ran in 5 years, i have a clean fuel tank, new pump and filter, and great fuel pressure, oil pump is new and great oil pressure, 1000cca battery new, new starter and wires added ground to block and frame, new distributor, wires and plugs, cylinders pressure checks look good 125-140, the timing is set correctly( did it with the motor out),positive there are no vacumn leaks, egr functioning right, I have had this car 23years and done all my own work, it lacks all peformance put in gear(4speed, cutch good), no engine trouble codes, so here is the kicker i can remove spark plug wires change them around 3 at time and no change in the way it is running, if i pull number 4 wire it dies, no others it just runs as it did, im 66 yo and worked on all my cars my whole life but i gave never seen this, is this the ecm causing this ( coil is new also) any help will be appreciated!!!
I did reset the timing to the aldl being jumped, 5 yrs ago i put a new cloyes timing gear and chain, the car spun on blocks and trapped me i pushed it off and had surgery to remove 4 bones from my wrist, so it was a year plus before i trided woking on it, recently i pulled the engine to verify everything... it definately has me stimpped
Howdy yall, I am working on a 85gt stock , Im having trouble running right, this car has not ran in 5 years, i have a clean fuel tank, new pump and filter, and great fuel pressure, oil pump is new and great oil pressure, 1000cca battery new, new starter and wires added ground to block and frame, new distributor, wires and plugs, cylinders pressure checks look good 125-140, the timing is set correctly( did it with the motor out),positive there are no vacumn leaks, egr functioning right, I have had this car 23years and done all my own work, it lacks all peformance put in gear(4speed, cutch good), no engine trouble codes, so here is the kicker i can remove spark plug wires change them around 3 at time and no change in the way it is running, if i pull number 4 wire it dies, no others it just runs as it did, im 66 yo and worked on all my cars my whole life but i gave never seen this, is this the ecm causing this ( coil is new also) any help will be appreciated!!!
it could be the ecm but that sounds much more like you have dead plugs or stuck closed intake valves. is this a 4 cylinder or v6? 85 was the first year for the v6. if it is the v6 sometimes the valve preload is too much and compresses the valve springs before reaching preload which uhh doesnt really help anyone edit: before someone yells at me i have seen a few 85 gts with a duke still. not sure if they were ordered like that or not but my guess is not.
[This message has been edited by cartercarbaficionado (edited 06-02-2025).]
Backprobe the 6 position connector where the injector harness plugs into the engine harness. Google backprobing to see what it is. With the connectors still plugged together and with the engine running check the pink and the pink black wires. Each should have +12v on them. Next using the probe check the Lt. Blue and Lt. Green wires. Each should show +12v most of the time and should show ground quickly.
If you aren't getting the 12v on the pinks check the fuses.
If you are getting the pulses on only one of the lt blue or lt green wires you might have a wiring problem or a bad ECM.
If any of the obvious circuit checks do not produce anything unusual then it may be time to consider buying a scan tool that will provide live data like O2 sensor and MAP readings. BTW with 123456 engine timing if one cylinder goes down you may or may not hear it.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Backprobe the 6 position connector where the injector harness plugs into the engine harness. Google backprobing to see what it is. With the connectors still plugged together and with the engine running check the pink and the pink black wires. Each should have +12v on them. Next using the probe check the Lt. Blue and Lt. Green wires. Each should show +12v most of the time and should show ground quickly.
If you aren't getting the 12v on the pinks check the fuses.
If you are getting the pulses on only one of the lt blue or lt green wires you might have a wiring problem or a bad ECM.
You nailed it sir, the injectors are the problem, the fuse was blown on one bank of the injectors, after testing all of them i only had 2 fireing, and i could not get those to spray with the test kit i have... thank you very much!!!
Backprobe the 6 position connector where the injector harness plugs into the engine harness. Google backprobing to see what it is. With the connectors still plugged together and with the engine running check the pink and the pink black wires. Each should have +12v on them. Next using the probe check the Lt. Blue and Lt. Green wires. Each should show +12v most of the time and should show ground quickly.
If you aren't getting the 12v on the pinks check the fuses.
If you are getting the pulses on only one of the lt blue or lt green wires you might have a wiring problem or a bad ECM.
You nailed it sir, the injectors are the problem, the fuse was blown on one bank of the injectors, after testing all of them i only had 2 fireing, and i could not get those to spray with the test kit i have... thank you very much!!!
