I have a 91 firebird 3.1 and am in need of help. It ran fine one day and the next day it won't start it sputters and wants to start but just won't. The fuel pump runs and has pressure at rail, has good spark at all 6 plugs recent tune up, new fuel filter, checked fuses, swapped the ecu, map sensor, egr valve, ignition coil with used ones from junk yard. I've tried spraying starter fluid in throttle body, adjusted timing. I cranked engine with injector fuses pulled engine didn't sputter put them back in engine sputtered so I assume that the injectors work also there are no codes present. I am running out of ideas and would appreciate any help or suggestions.

Thanks,
Jim

 

hey, if it just suddenly stopped working one day to next with no changes and no codes my guess is airlock in fuel system poss??- after filter change and stuff, or bad coil ??- they can just 'go' when they feel like it.
its a toughy when theres no warning !! ill keep thinking........

 

I'm gonna go with a coil that's gone bad. You may have spark outside the engine (no compression approx. 10KV req), but once you try to fire a gap under compression you can't (approx. 25-30KV req).

 

I've bought a brand new coil still doesn't start and I swapped the ignition module with a used one same thing no start. NO IDEA?

 

I had a similar start/running problem to what you have. Found that the ECM somehow went bad. I did not have any error codes pop up either. After replacing the ECM with a new one, my problems were solved. Hope this helps.

 

Get a fuel pressure tester and see how much pressure there is.

Should be 39-41 psi

Could also have a bad timing chain.

 

Have you ran a compression check on this motor yet?..could you post them if you have ?.Does the SES light flash when you ground it?.

 

I have not tried comp test and the ses light flashes code 12 which is normal but no other codes present.

 

Try a NEW ignition module and/or checking the connections on the pickup coil. Since you have taken care of everything else, that't the only thing left. The pickup my have failed, or you may have a broken wire running to the ECM or coil (check both ends of the dizzy/coil wire from the module).

 

ohm out the injectors... if one is shorted, it will keep them all from firing...

 

Today I ran a compression test all six are between 150 and 160 psi so I guess I'll have look else where.

 

Had all the same problems on my own car here recently. Replaced fuel filter, spark plugs, distributor cap and rotor. Still the same. Changed my ignition coil and it ran fine. I'm not saying your new one is garbage, but I've read that they can still be bad and be brand new. I'd say, go buy a brand new one from the part store, mine was Niehoff brand. Incase it's the same for a 3.1. It's only one boot plug and two clip plugs, I would just hook it up and set it in there than try it, if this doesn't help still, than I'm not sure, you can still bring the part right back and say it didn't work. My next part was going to be my fuel pump. But, try it out and let us know. Good luck with the Fire-chicken

 

Well along with buying a new coil I took the coil off my 2.8 s10 with runs fine and is the same part # and it still does the same thing so I don't think it's the coil.

 

Well today I got a fuel pressure tester and a noid light I have 41 psi at the fuel rail and I have an injector pulse at all 6 injector wires. I also swapped out all 6 injectors with used ones still same thing sputters wants to start but just won't. I'm running out of ideas it's driving me crazy I guess the only thing I have left is to get another distributor.

 

Same thing on mine. Does the Idle air control valve hum? I found that I had a vacuum leak on the grommet at the back of the Throttle Body. Good luck!