I am new to this forum, and I wish I came on as a happy user, but after 2 days of diagnosing my 85 Supra with the stock 5mge motor I am getting a little frustrated.
This is how the weekend started and a description of what happened:
I was driving home from work on Friday and my car started to miss, I revved it a couple of times and it really bogged down and idled down to 200 rpm and was really rough and knocking, I decided to park it and call a tow truck.
I got it home and it wouldn't turn over and run for more than 5 seconds. I went through the Haynes manual and it gave me 3 options, timing vacuum and fuel. I replaced the fuel filter ( 300K on the motor and the fuel filter had a toyota sticker on it, my fault should have replaced when I first bought the car), can't check timing and checked all of my vacuum lines, no problems with the lines.
I then read the codes to the computer and it came up with a TPS sensor bad, replaced that, nothing. Cleaned the intake, checked the compression ( see if the timing belt skipped, 150 psi all 6 !!). Checked the MAF sensor with the resistance tolerances and they were all good, replaced the wires and the plugs cause they were cooked. Checked the coil and it came up within the tolerances of the manual, nothing, the igniter module comes up ok. I am at a loss WTF do I look at next ???
I am thinking fuel pressure regulator or fuel pump, but don't wanna go there without checking first, and I don't want to check if it is a waste of time.
I also checked all the relays and fuses in the power distribution box and the main relay and the EFI were really friggin' hot but still clicked on and off.
If you have yet to check the air intake piping that sits on top of the valve covers that goes to the throttle body then check it.....that rubber coupling that connects the hard plastic pipe to the throttle body can crack on the bottom ridges....when it cracks it lets all the air out of the system.....When its cracked like this you will be able to start it and keep it running for no more than five to seven seconds, then it automatically dies.....Mine was ripped up and I did not even know.....I replaced the ecu, the tps, the ISC valve and a million other things before I found that damn crack under there......I was glad that's all it was..................Also use the fuel pump check connector near the AFM.....see if that baby runs or what....good luck
By the way I got an 83' MKII ECU(MT)........an ISC, TPS, and an Igniter box, .....I'll let em go cheap if anyone needs them!!!
yeah, I checked it and it was cracked so I used the magic of duct tape to fix it and it didn't help. I also did a check on my mass air and the manual said to move the flapper inside the sensor and read the output and it was very erratic, especially if I held it in a position half way open it would bounce between the max and min ranges on the ohm meter without me even moving the flap.
HEY SEAN85SUP, CHECK THIS OUT IT ALMOST SEEMS LIKE YOU HAD THE SAME PROBLEM AS ME CHECK MY POST ON 10/14/03 TITLED ENGINE. I GOT TIRED OF JACKIN' 'ROUND WITH MY 85 SO I SENT IT TO THE DOCTOR AND CALLS ME BACK AND SAID IT WAS THE STARTER?? YEAH I KNOW IT'S HARD TO BELIEVE HUH THE FRIGGIN' STARTER. THE CAR CRANKED AND EVERYTHING BUT IT WAS SHORTING OUT CAUSING THE INJECTERS TO SHORT OUT. I DON'T KNOW IF THIS WILL FIX YOUR PROBLEM BUT IT FIXED MINE TODAY
I can get it to run, but, I have to play with the flapper in the MAF sensor and then I can give it the gas without any hesitation, but without a screwdriver in the flapper and constant manuevering I can't get it to run smoothly. It idles very eratic and runs ultra rich otherwise. It also backfires through the intake hose when revving without guessing at where the MAF sensor should be. I have the intake valve cover off thinking that I had had a bad spring or sticky valve that was detanating it back through the intake manifold.