1989 Supra will not start
 

Just finished a 4 month long MHG replacement with my son. It was a project to for us to do together and for both of us to learn as we went along. Now we are so close to the end, but getting very frustrated. After closing up the engine after the rebuild it started on first try and then died after a few minutes. Replaced Distributor, reset computer and it started and ran. Took for a test drive and it ran fine. Shut it down and now it will not start. Prior to replacing distributor when it would not start the first time, I tested for spark and no spark. Replaced coil-nothing. After replacing distributor, it started fine. Now, again, no spark. Prior to replacing dis again and having the same results, I am trying to find out from the experts here if there is anything else that could be wrong. Tested resistance for distributor and AFM and both were within tolerance. Wondering if a no-start "signal" is being sent from computer. Why would it start and run fine and then not start? Have tried to follow the TSRM, but am stuck. Have rechecked all the grounds and they are secure. Battery voltage is 12+ and getting 12+ on the grounds too (engine/firewall/grounding points). Timing set while running - no problems. Only codes is 12 and 51 and not sure if they is related or not. Tried to follow TSRM on the codes, but can't seem to get anywhere.

1989 Supra mkiii non-turbo manual

Thanks for helping.

Almostrunning

The code 12 could be a significant part of it. A code 12 may get set if the vehicle is "pop" or "push" started.

As for the code 51, feathering the throttle or turning on the A/C while in diagnostic mode will trigger it; BUT once the throttle is close or the A/C tuned off it should clear after a few seconds. If it remains see the EFI section of the TSRM and then the Throttle Body section therein.

Hve you checked your fuel pressure and made sure all grounds are clean and solidly connected?

http://www.cygnusx1.net/Supra/TechTi...ror_codes.aspx

Thanks for the reply. The car was not push started. I have read your info on 51 and I don't think it is causing the problem, but what do I know, I am the one with the problem. The car was always started normally. As I wrote, I have checked all the grounds and as far as I can tell with the meter, there is not a problem. In following the TSRM, I am not getting any abnormal readings. Am I missing something? The distributor replacement that initially solved the problem has me baffled as to why that would be the issue, when I was getting no spark off the coil prior to replacing it. Some might point me to the ignitor or the ECU, but I am trying to get some expert advise prior to replacing them as the distributor solved the problem before. The issues may not be related but....

Thanks
Almostrunning

Does it crank at all?

Sorry if I was not clear. It does crank over, no spark off coil. As I said, the car ran great one minute and now no spark/start.

Thanks
Almostrunning

well, if its no spark from the coil...i would think it either a bad coil or ignitor. or low primary input voltage..?

OK... Nothing showed up in the testing. Put a second new distributor in the car and it started right up. Ran great. Drove for 10 miles and after shutting car off it would not start again. Engine turns over just fine. With the first new distributor, car turned over but no spark. After replacing only the distibutor it started just fine. Same thing is repeating itself and I am at a loss as to why. It is a little costly to replace the distributor every time I want to start the car....
Any ideas?
Thanks,

Almostrunning

I would very thoroughly and carefully inspect the wire harness running to the distributor.