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1991 Pontiac Firebird no spark


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Wujman
User

Nov 7, 2016, 3:34 PM

Post #1 of 7 (2321 views)
1991 Pontiac Firebird no spark Sign In

I just bought a 1991 Pontiac Firebird with the 3.1L V6 engine with about 130k miles on it. I got it for really cheap because it wasnt running when i got it due to no spark. I decided to replace the distributor cap and rotor. Both the cap and rotor were very deteriorated so I thought that might be the problem and no luck. Then as I pulled off a wire to test spark it basically fell apart as I took it off. So I bought new wires and still nothing. I grabbed a volt meter and am getting power to the ignition coil when the key is on and thats about as far as I've gotten. I'm pretty stumped and am hoping I don't need a whole new distributor because I'm not exactly sure how to time it properly. Any help would be very appreciated.
-Wujman


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Nov 7, 2016, 4:05 PM

Post #2 of 7 (2310 views)
Re: 1991 Pontiac Firebird no spark Sign In

Sounds like it's probably been messed with a bit already if you got it with no spark found. How are you so sure now with new plug wires you should easily be able to see it or not with a spark tester.


You could also check the wire from coil thru a tester to ground and watch if it blinks or rule out another problem - just take distributor cap off and see if rotor spins in your hands, engine off, key off.


IDK but would also check connections to and wires to ignition module inside distributor. I think (wild guess) five wires to it with a plug at each end - any issue you won't get spark.


A look down shows module in this picture was common to just blow for no reason known to me no longer quickly found separately?


Here's a picture looking down at distributor with a new module and yours should look like this without the sticker if original?

See shown the green and white wires as well. They can't be pinched or insulation rubbed thru for some easy checks,


T



Wujman
User

Nov 7, 2016, 4:20 PM

Post #3 of 7 (2308 views)
Re: 1991 Pontiac Firebird no spark Sign In

Thank you for the quick response! I will try what you've suggested as soon as I am able and get right back to you with the results.


Wujman
User

Nov 7, 2016, 4:36 PM

Post #4 of 7 (2307 views)
Re: 1991 Pontiac Firebird no spark Sign In

I did a little quick research on the part you were speaking of and would it be the Ignition Control Module (ICM). Ive found them on rock auto that look to be what you are referring to. It seems to have both plugs and has a heat sink on the underside. Also it seems to be implied that it mounts on the distributor in the way it shows on the picture you gave me.
-Wujman


(This post was edited by Wujman on Nov 7, 2016, 4:39 PM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Nov 7, 2016, 4:58 PM

Post #5 of 7 (2301 views)
Re: 1991 Pontiac Firebird no spark Sign In

? Heat sink? IDK - not sold where I looked for that picture which was Autozone just easier for me for pictures.


Those that failed instead of a heat sink it was "electric grease" you put under it to cool to plate below it. Once just two types and carried one of each known to work for road calls for dead vehicles because of not spark hoping to fix on the road if possible.


Did see they sell some so called high performance ones which is most likely total bull crap. Try not to fall for that. Said many times here if something is said to be better than OE design that much it would have been used OE to begin with,


T



Wujman
User

Nov 9, 2016, 12:24 PM

Post #6 of 7 (2276 views)
Re: 1991 Pontiac Firebird no spark Sign In

Well I bought a ICM from my local Autozone and just got done installing it and it fired right up! drive it down the street and back and I have to say it was a very sweet sense of victory. You are a life saver and I'm not sure I would have been able to think of that. The old module seems to have burned out due to bad heat transfer between the metal and the thermal grease due to old and dried up thermal grease. I replaced it with computer grade thermal compound I have for computer processors that should last for about 15 years. Thank you again for helping me with this, I owe you a good deal.
-Wujman


Tom Greenleaf
Ultimate Carjunky / Moderator
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Nov 9, 2016, 1:34 PM

Post #7 of 7 (2273 views)
Re: 1991 Pontiac Firebird no spark Sign In

They were just common enough I carried a spare with me and didn't own a GM anything when those were used. Road calls. No serious testing just found a no spark and if wires were good put mine in in 1 minute either worked or didn't so no loss.
The grease that used to come with them just helps it stay cool to mounting surface not the definition of a heat sink.


Life expectancy of these was never known to me. Some lasted forever some went a couple times on the same car so no pattern or time limit for failure known to me.


Glad it worked. They should be dirt cheap by now,


T







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