93 t/a in trouble

[N20LT4Bird]

Originally posted by TRANS AM IN EUROPE
is there any other way to check that?

after it stopped, it started again after a lot of tryes

Not really a better way to check the valve operation other than a compression test.
After it started again, did it run OK or was it real rough?


If you have good compression, here are some things to consider:
If you have fuel, spark, compression and the correct timing of all of these - the engine will run.
You seemed to think the car has fuel and spark, but you said fuel pressure was bleeding down. You want to check to make sure the injectors arent shorted to ground in the harness somewhere or stuck open some other way - fouling the plugs out with fuel. Injectors have constant current going to them and the ECM grounds them for a pulse. It is not enough to check for just power at the injectors - you must see that they are pulsed.
Also, pull ALL of the plugs. This may be a PITA, but it will give you valuable info on whats happening in the combustion chamber of each cylinder. Consider these things and let us know!

[Trans Am]

After it started again, did it run OK or was it real rough?


After it finally started it ran ok at idle or driving without pressing too much the accelerator. Pushing lightly the accelerator reved up ok. when i pushed it all the way the engine stumbled ,almost stopped and the headlights went briefly off. i could drive it tough. i drove for about 10 minutes slowly, stopped , waited for 10-15 mins , then i started it again after 2 or 3 long tryes. I drove for 5 mins , then let it idle for 10 mis or so in the parking lot. it never started ever since.


I checked the injector pulse with a test light : ok, injectors + reference with key on: ok. also i lifted the fuel rails and injectors spray fuel while cranking the engine. just #2 injector was leaking and i blocked it. inow it doesnt leak, but no fuel goes to # cylinder. i think the car should start on 7 cylinders anyway.


oh yes it is a real PITA taking the spark plugs off, especially no. 8. i did it without going under the car.
after cranking the engine a cuople of times, i took out the plugs (theyre new) and they were not wet. i didnt even smell gas.

I know it seems like a fuel problem, but after i lifted the rails and saw the injectors spray, i dont know anymore

i ll go crazy

[N20LT4Bird]

Did you check compression yet?

[Trans Am]

Originally posted by N20LT4Bird
Did you check compression yet?

still trying to get a gauge

if the timing chain jumped is it possible thati i have compression?

[N20LT4Bird]

Yes, depending on where the chain jumped to, you could still have compression.

[Trans Am]

Originally posted by N20LT4Bird
Yes, depending on where the chain jumped to, you could still have compression.

so Ill have to check the timing chain now? can I check without taking off the water pump and the opti?

[N20LT4Bird]

Do the compression check first because youre checking other things besides just the timing chain. If you want to check the timing chain, an easier way would be to bring the crank to 0 deg BTDC and check the valve position with the valve cover off.

[stange567]

what does the car sound like when it is turning over?? does it make a popping/backfiring sound at all?? if so i would take all the plug wires off and put them on again.. u might have them fvcked up.. i had this happen with my bonneville.. pissed the hell out of me..

[stange567]

and even if on cylinder does horrible on the compression test the car will still run..

[Trans Am]

Originally posted by N20LT4Bird
Do the compression check first because youre checking other things besides just the timing chain. If you want to check the timing chain, an easier way would be to bring the crank to 0 deg BTDC and check the valve position with the valve cover off.

ok
how do I do that?



the engine turns ok, doesnt even seem to catch. just turns

[N20LT4Bird]

Well, you first must get a guage (duh), disconnect the coil wire, and then take out the spark plug, thread the guage in its place and crank the engine over a half dozen or so times with the gas pedal to the floor. Im thinking the guage should read in the 150 PSI range, but you may want to double check on the PSI specs. I could be off on that - im trying to go by memory.

[Detroit_Bird]

Hey Trans Am In Europe-

Just went through what you're going through and found out my coil was firing the plugs but was too weak, and was only firing every 2-3 times that it should have been. I've never been so stumped before, and this was the solution.

Hope this helps-

[Trans Am]

i am thinking there is rotor damage
i checked 5 plugs for spark , and only 2 were ok. maybe i didnt check as i should, i ll try again tonight.

Is it possible that the opti is bad if i have injector pulse ?

i have spark at the coil. i think its ok, but the resistance is ~10.000 ohms instead of ~7.000. it that bad?

[Trans Am]

I fixed it

I m the happiest man alive!!

Turns out it was a weak ignition coil! and optis are not that bad: i took it apart and it still works

Thank you all for the input