7mgte start, run for 2-3 seconds...then die...every time

[nothingbetter]

Hey all. I'm really stumped and was hoping someone here may have the anwser. I recently bought a 1985 toyota pickup with a 7mgte swapped in. When I bought it it ran fine but had some major blow by so I rebuilt the engine. My father helped me with the rebuild as he is a journeyman mech and worked in engine shops for years. It was rebuilt correctly. After I got it put back together, we fired it up and it started fine but quit after 2-3 seconds. Very confused we tried many things to keep it running. I put a test light from ground to the tan wire coming out of the coil pack, the light went on. I started the engine to see if that wire lost power for whatever reason...and it stayed running this time. We then set the timing to 10 degrees. I could drive it around with that little test light on the wire. Still trying to solve the problem, I was going to start it this morning to warm it up before trouble shooting, but now my test light gimmick wouldn't keep the engine running. My dad and I are both running out of ideas and would like some other opinions on how to get it running properly. we can keep it running by working the throttle. It has an Apexi super air flow meter. I just sent an e-mail to apexi seeing if they have had similar problems before. Do you kind folks have any ideas?

 

[supramn21]

did u reset the apexi to karma signal and is the afm plugged in also check all grounds and the wires on the harness can become brittle and the wires can split easly

 

[nothingbetter]

I havn't reset the apexi but I'll give it a shot this weekend when I'm home. I know the afm is plugged in but it hard to trace as the electrical in this truck is a mess. If you have any more ideas just shout em out. It getting real tempting to follow my co-workers advice and "scrap that piece of scrap metal and get a real engine. Ain't nothing a chev 350 can't do"

 

[87M-GTE]

I havn't reset the apexi but I'll give it a shot this weekend when I'm home. I know the afm is plugged in but it hard to trace as the electrical in this truck is a mess. If you have any more ideas just shout em out. It getting real tempting to follow my co-workers advice and "scrap that piece of scrap metal and get a real engine. Ain't nothing a chev 350 can't do"

Keep at it, don't become another sack-ridder like your co-worker.
It is something electrical from you're description, maybe get a TSRM look at some wiring diagrams, check your grounds, etc.

Sam

 

[Nick M]

If you can't find other things, check DTC's. If you have spark, but the spark confirmation is lost, the car will start, then stall after a couple of seconds.

 

[nothingbetter]

dtc?

 

[nothingbetter]

I plugged in and reset the Safc. No difference. Using a test light I know that the coil pack is grounded and that the ignitor is grounded. I got 3 codes when it wasn't running. 14, ignitor signal missing to ECU 4-11 times in succession, 24 Intake air temp sensor open or short and 52, rod knock sensor signal circuit open or short. Does anyone know where I can get a good wiring diagram for a 1987 7mgte? After much searching I can't seem to find one worthy of anything.

 

[Fubar231]

http://cygnusx1.net/Supra/Library/TEWD/MK3/default.aspx

Toyota Electric Wiring Diagram online for ya

 

[Nick M]

dtc?

Diagnostic Trouble Codes

Do you understand that if you have spark, but lose the spark confirmation signal, the car will start, then stall. I don't know that is your problem, but the symptom fits and should be looked at.

 

[nothingbetter]

and how would I go about checking that? This is something I havn't delbt with before

 

[Nick M]

Do you know how to pull the codes?

Have you looked at the air intake after the airflow meter and before the throttle body? A good sized gap will cause a stall unless you bring engine speed up a lot.

 

[nothingbetter]

I got it figured out. When i took it apart at the beginning of the rebuild process2 of the 4 wires on the harness going into the coil pack popped out. I pushed them back in where I thought they came from. Turns out I put them in backwards...dumb mistake. Oh well. Thanks for the help and all your opinions and ideas!