I HAVE A 86 TRANS AM W/TPI FUEL INJECTION AND IT CRANKS OVER BUT WONT START. THERE IS NO SIGNAL GOING TO THE INJECTORS. SO I JUST BOUGHT A NEW ECM AND A NEW PROM. THAT DIDNT FIX THE PROBLEM. THERE IS SPARK BECAUSE I SPRAYED STARTING FLUID INTO THE INTAKE AND STARTED FOR A COUPLE OF SECONDS THEN DIED AGAIN. WHAT DO YOU GUYS THINK IT IS. WOULD APPRECIATE SOME HINTS AND HELP.

 

man I wish people would stop recommending new PROMs to people with no-start problems.


I bet it's got somethign to do with VATS, your fuel pump, or a relay.

 

I HATE TO TELL YOU THIS BUT TO MOST THIS IS SHOUTING... TO OTHERS IT READS LIKE A RETARD IS TALKING.

That said, no VATS on an '86. Did you test both banks for signal? Have you checked the fuses? Have you checked for codes? Have you bought a Chilton's or Haynes (or both) book yet? See where I'm going with this?

 

was vats 87+?

 

From what I gather GTA's got them in the latter part of the '88 model year. The rest of the f-body line got them in '89. I still haven't gotten a clear indication of the first year for the vette... too lazy I guess.

 

Assuming it's not the ECM, or fuses (you have 12v to one side of the fuel injector connectors,) or a VATS problem. It would really suck if all 8 fuel injectors are bad. Then it may be a grounding problem, check the copper braided straps bolted to the firewall behind the heads, not just visually, use a meter, or a test light, should get a very bright light from the battery+ to the strap. The other thing to check is the 2 common ground wires (one for each bank) from the injectors to the ECM.

Good luck and let us know what you find, I've read many a post with this problem.

 

THERE IS NO CODES FLASHING ONLY THE CODE 12 BUT THAT IS NORMAL AND I CHECKED ALL THE FUSES AND THE BANKS ON BOTHE TERMINALS ON THE INJECTOR CONNEECTION WITH A NOID LIGHT AND NOTHING

 

I HAVE A 86 TRANS AM 5.0 TPI AND IT WONT START BUT IT CRANKS OVER I CHECKED IF THERE WAS ANY SIGNAL TO THE INJECTORS WITH A NOID LIGHT BUT THERE WASNT. I JUST BOUGHT A NEW ECM AND A NEW PROM BUT DIDNT CHANGE A THING CHECKED FUSES CHECKED CODES ONLY CODE IT FLASHES IS THE CODE 12 WHICH IS NORMAL????

 

Had the same problem once myself, not saying this is your problem but it turned out i had a bad prom chip, and it was brand new too.
My wifes fuel pump went out and when i checked, the noid light was operating,i don't think the two are related.
1986 is your answer

 

I hear all too frequently as a first response to TPI related problems: replace the ecm. Honestly, I haven't heard of a single time when replacing it fixed the problem. I'm not saying they don't go bad, just that problems are usually the simple, obvious, and overlooked things.

edgar, the amount of help and how useful that help is depends not on everyone else, but on you and your ability to provide details. Start off by stating some of the more important, but simple things... was any work done to the car recently? Did this problem come up all of a sudden after driving fine?

First thing off the top of my head: the injectors always have power on one terminal, and the ecm grounds them when it wants them to fire. Check with a voltmeter that one of the terminals has 12 volts. Check all your ground wires at the back of the heads.

The ecm grounds the injectors to fire them when it receives a reference pulse from teh distributor. Pick up a wiring diagram, figure out which wire is it that sends the ref pulse, and make sure the ecm is receiving that pulse. If its not, your problem is downstream from there. If it does get a pulse, then I'll have to think a bit and get back to you. Let us know...

 

As 92blue, and I said the ECM should pulse to ground one side of the injector connector, which is why the injectors don't fire, so the noid won't work either because it just takes the place of the injector.

You have checked for 12 volts at the fuses, but is it present at the injector connectors?, if it is then determining why the ECM isn't firing is the next step, which is why 92blue asked for you to check for the reference pulse (1.3 volts while cranking/running) from the distributor (I believe it's a purple wire with a white stripe) 4-wire connector.
Once the pulse passes through the amplifier the pulse is fed to 2 solid state relays, one feeds the coil the other feeds the ECM. So even if you're getting spark, the ECM distributor reference signal could be dead.

If you're sure the wiring, fuses, and ECM are all good then, you might try changing the ignition module, it's not a high ticket item.

 

Edgar,

Get your voltmeter and test the voltage at the injector connectors with the ignition turned on. You should have 12VDC between every connector and a good ground. If the voltage is present, the INJ fuses are good. If not, check the fuses in the fuse panel, positions INJ1 and INJ2.



You should also remove a plug wire or two and check for spark (carefully, of course). If there is no spark, it may be because the distributor is not generating reference pulses from the pickup coil and/or the HEI switching module is not working. Without this reference pulse, the ECM will not fire the injectors. Even if there is spark, you need to test the input from the HEI module to the ECM (the purple/white wire).

 

If you notice some duplication of posts, this thread was merged with the same thread from the TPI Forum.

 

CHECKED THE BACK OF THE HEADS AND THERE WERE THREE WIRES. BUT OF THE THREE ONLY TWO WERE CONNECTED FOR GROUND. I CANT CONNECT THE WIRE THAT IS NOT CONNECTED BECAUSE THERE IS A HUGE STORM COMING OUR WAY TODAY SO ILL DO IT TOMOROW AND ILL GET BACK TO YOU.

 

this is going to sound like a really dumb question, but how do you check the spark?

 

hey edgar did you ever figure out the problem my ta is doin the same thing

 

Sorry to zombie this basically 7yr old thread, but I just replaced all the upper gaskets on my 86 TPI. It will turn over but not start. Im pretty sure the problem lies somewhere with the distributor being taken out and amateurly reinstalled. It has gas, the fuel pump is priming, there is fuel pressure (no exact reading), fueses look good, battery is charged.