Hey guys and gals! need some help please! I have a 91 rs w/305 tbi have,nt had too many problems til now, for the past month or so it sometimes coughs and backfires thru the tbi on slight to moderate acceleration, timing is fine, new plugs, cap rotor, wires and is maintained good, but today the check engine came on! but after shutting it off and restarting it did not come on again! now tonight it quit while driving at about 30 MPH and when i tried to restart it backfired and shot a nice flame out the carb! now she wont even fire, is getting fuel! so has to be ignition right? could it possibly be the ignition control module? or hate to say it! timing chain jumped? I could really use some help? cause i cant find my chiltons book! Thanks ASAP would be greatly appreciated.

 

If the light is on get it scanned, that will start you in the right direction instead of running in the dark.

 

No the light is not on anymore, after shutting it and restarting it later it must have reset the code? also i did drop the negative terminal off! to clear the memory, but it might have a hard code? so i will have it scanned, thanks for the input! i appreciate it.

 

Just to clarify though it still wont start?

 

Nope just cranks, and no fuses blown or anything visable! she just quit and that was that! but it had been popping and backfiring under moderate acceleration for about a month now! and now that i think of it the tach started to fluctuate, around the same time! and never did before. and isnt the pick/up sensor for the tach in the distributor? so ignition module is looking more and more like the culprit? unless someone else has had the same prob, and found that was not the case? please let me know! i need my car fo work and have only friday and saturday to get it fixed. Thans again for any and all help[sm=americanasmiley.gif]

 

If this has a HEI dist, there are 2 wires that go to the pick up module. They have insulation wrapping around them. If those wires ground out, it causes what you are saying. Unplug those wires and check them good. You won't see it from looking down at the wires, they erode from the bottom. Just pop the cap, and check those wires...

[IMG]local://upfiles/2372/0C2808ED326A4C15890D500738E42083.jpg[/IMG]

The green and white one with the connector that is unplugged in the pic.

 

[&:] a helpful hint any good chevy guy with an hei carries a spare module in the glove compartment i think we need to verify that we dont have spark before we start messing with the dist. or maybe see if the dist is going round and round as well as still being lined up on # 1 cyl for timing. we need to check electrical as well as mechanical so take a peek at the mentioned items and get back to us kurt

 

Iwould take the cap off and turn the crank by hand kinda back and forwards and see if there is any playin the timing chain to rule that out.

 

Thanks for all the great idea,s and will check all of them! Also it does have an HEI distributor but looks alot different then that, mine does not have the coil in the cap but love the visual aide! My68Camaro, and will get back hopefully with great results probably saturday afternoon. Again i reall appreciate all of the great advice. [sm=goodidea.gif]

 

Timing chain check is simple. As long as no one has messed with your distributer Check your timing. Do not crank the motor more then 15 sec. Let the starter cool for 2 minutes before trying it again. If your timing is close you did not jump a tooth. To effect your car as much as you say it would have to have jumped a tooth, Chains just don't stretch that much.

While spark modual is the most common issue most of the time they fail completely. I did say most. Otherpossibilities are coil and pickup and/orplay in your distributer. Also moisture in the cap. First thing I would do is check for weak spark. Just about any parts store should have a spark tester. I like these http://www.sjdiscounttools.com/kd2756.html. This is a quick way to test the whole system. It will not tell you whats wrong just that its something in the ignition.

If your timing is right and you can fire you spark tester then it gets kind of ugly. You need to check your fuel pressure. I'll just stop there no need to depress you. There is a real big chance its in you ignition system

GL