Stock 7mgte in 85 MK2 auto, 86-88 ECU, 35k mi on rebuild, DDP, no cat, 3” exhaust, new plugs 2k mi
EARLY TSRM http://www.supra.co.nz/87tsrm/EFI/efi31.htm
Long term issues:
Code 51 (over 2-3 years) that has survived TPS resets. Testing the disconnected TPS harness connector still gets the code 51. AND also occasionally have a neutral start switch issue where I have to use neutral position not park to start.
Often on warm restarts, would have a miss lasting a few minutes or would go away if I did a couple of 3k revs.
Cold engine starts were not the single kick, but were a few spins.
STORY: Parked overnight no start and code 12 only. My pro wrench, Tony Orta, called an internal CPS wiring issue. He redid the internal CPS wires and dropped it back in. Showed only the 51. Seemed to start quicker and a bit more responsive.
A few days later, after a no start I found a broken CPS harness side wire and a broken O2 sensor wire probably from from the CPS R&R. I cut cleaned and twisted them together. I reset the TPS and I replaced the FPU valve under the intake manifold with a brand new one. Reset the timing. I also opened the longtime plugged charcoal canister line from the gas tank to the air (no canister). Cleaned up the engine grounds.
BUT the restart miss was replaced with low speed pedal off coasting afterfire/muffler explosions, and my MPG went from a poor 17-18 down to a 10-11 mpg although driveability seemed ok. It had been 19-20 for my driving before the plug replacement brought on by the MPG drop to 17mpg. There had never ever been afterfire/muffler explosions
NOW: My reconnected CPS wires started to show some poor connect/disconnect. The MPG is bad with the afterfires. Codes 12 and 51 are both showing.
Need some guidance as I currently have limited physical resources and time and Orta is not readily available.
Q1. Thought code 12 blocked other codes until cleared. What is the distinction when it shows with other codes?
What does 12 with another code# do to ECU/EFI management?
Q2. Would a poorly connected O2 sensor wire send the ECU into a default mode? If so, what would that be?
Q3. When the 51 refers to a NSW issue and not a TPS issue, what does the 51 cause the ECU to do or not?
Q4. Is there a cold start injector issue that overpumps gas after engine starts? Could I test by disconnecting that injector?
Q5. Would the poor CPS wire connect create the code 12 but still let the engine run??
Q6. Does shorting the disconnected TPS harness connector and getting the code 51 mean that the TPS wire circuit is the issue or does it rule out the NSW circuit/switch or not?
Have spent countless hours on searches which helped refine the questions but haven’t completed the answers.
EARLY TSRM http://www.supra.co.nz/87tsrm/EFI/efi31.htm
Long term issues:
Code 51 (over 2-3 years) that has survived TPS resets. Testing the disconnected TPS harness connector still gets the code 51. AND also occasionally have a neutral start switch issue where I have to use neutral position not park to start.
Often on warm restarts, would have a miss lasting a few minutes or would go away if I did a couple of 3k revs.
Cold engine starts were not the single kick, but were a few spins.
STORY: Parked overnight no start and code 12 only. My pro wrench, Tony Orta, called an internal CPS wiring issue. He redid the internal CPS wires and dropped it back in. Showed only the 51. Seemed to start quicker and a bit more responsive.
A few days later, after a no start I found a broken CPS harness side wire and a broken O2 sensor wire probably from from the CPS R&R. I cut cleaned and twisted them together. I reset the TPS and I replaced the FPU valve under the intake manifold with a brand new one. Reset the timing. I also opened the longtime plugged charcoal canister line from the gas tank to the air (no canister). Cleaned up the engine grounds.
BUT the restart miss was replaced with low speed pedal off coasting afterfire/muffler explosions, and my MPG went from a poor 17-18 down to a 10-11 mpg although driveability seemed ok. It had been 19-20 for my driving before the plug replacement brought on by the MPG drop to 17mpg. There had never ever been afterfire/muffler explosions
NOW: My reconnected CPS wires started to show some poor connect/disconnect. The MPG is bad with the afterfires. Codes 12 and 51 are both showing.
Need some guidance as I currently have limited physical resources and time and Orta is not readily available.
Q1. Thought code 12 blocked other codes until cleared. What is the distinction when it shows with other codes?
What does 12 with another code# do to ECU/EFI management?
Q2. Would a poorly connected O2 sensor wire send the ECU into a default mode? If so, what would that be?
Q3. When the 51 refers to a NSW issue and not a TPS issue, what does the 51 cause the ECU to do or not?
Q4. Is there a cold start injector issue that overpumps gas after engine starts? Could I test by disconnecting that injector?
Q5. Would the poor CPS wire connect create the code 12 but still let the engine run??
Q6. Does shorting the disconnected TPS harness connector and getting the code 51 mean that the TPS wire circuit is the issue or does it rule out the NSW circuit/switch or not?
Have spent countless hours on searches which helped refine the questions but haven’t completed the answers.