An Ignition Puzzle
An Ignition Puzzle
This gonna be hard to explain but please read, need Help
I'm trying to finish my '87 mpfi into a '83 carbed Firebird. I found a cheap parts car, and accually made money off it. I have changed over the fuel tank, wiring harness(no to mention new paint, rear suspension(including all bushings), and a soon to go in front suspension). And to make things difficult i decided to rebuild the engine also. So it wasn't a cut and dry take engine out put other engine in operation.
Anyways, my problem is I have NO SPARK. I wanted to replace the ignition coil anyways, did that, still no spark. There is power at the coil, the voltage drops as you turn it over.
I replaced the pick up coil and cleaned up the insides of the distributor. the old one gave me 765 ohms and spec is 500-1500. It looked bad so it's not a complete waste of 10 bucks I guess.
My firebird book tells me to take it to a qualified tech and the wiring diagrams are next to useless. However my Grand Am book is more helpfull, twisted my mind a bit since i don't quite understand whats going on in those diagnostics. That book is telling me to replace the distributor. The distributor is rather pricy, and i'm not sure thats my problem, i just can't see how.
The ECM is probably good, it keeps flashing a 12
The ignition module, I cleaned up the grounds on it. I haven't had it tested, but it's been my experience those don't just die, you get a weaker spark as the engine gets hotter and it backfires if you get mad and floor it (I blew up a muffler on a 2.8 olds with a bad module, it was great everyone ran like it was terrorist attack, it was very very loud). The parts car ran OK (even with blown maf fuse) before I gutted it.
I think my problem is wiring related. There is something i did mess with, and its gonna be hard to explain. Little clues tell me I'm not the first person with this problem on this engine. There was this wire that someone had going from the fusebox to a thick red wire on the engine harness (it has a clip on it if that helps) and there was another wire attached to a pin on a relay(the one that says 5/10min what is that anyway?, it is/was disconnected)and that wire wasn't connected to anything, it looked like it used to be a ground (it ran while that was disconnected). Any how I xnayed both wires, and took the red one and put that directly to the power distribution node. The inside electronics worked oddly without it connected to power (interior worked, no dash lights, radio illuminated but didn't show the time or radio station).
Anybody know what that was all about, I've seen that relay bypassed on other cars. How do you do that and why? Right now thats my prime suspect but I took that apart 4 month ago and can't remember exactly how it was.
Oil pressure sender? I lost the bolt for it and grabbed one from a camaro. shot in the dark, but can it be bypassed. I know the car not supposed to start with no oil, but will it turn over? Oh word of advise.. put that on before you put the engine in..I had to customize a bit.
I'm at a dead end here. I'm really getting unhappy about turning the car over and not starting. I spent some coin on that rebuild, especially the heads.
To be clear I'm hoping someone will tell me about that relay, and maybe some trouble shooting suggestions.
hmmm what would superman do?
I'm trying to finish my '87 mpfi into a '83 carbed Firebird. I found a cheap parts car, and accually made money off it. I have changed over the fuel tank, wiring harness(no to mention new paint, rear suspension(including all bushings), and a soon to go in front suspension). And to make things difficult i decided to rebuild the engine also. So it wasn't a cut and dry take engine out put other engine in operation.
Anyways, my problem is I have NO SPARK. I wanted to replace the ignition coil anyways, did that, still no spark. There is power at the coil, the voltage drops as you turn it over.
I replaced the pick up coil and cleaned up the insides of the distributor. the old one gave me 765 ohms and spec is 500-1500. It looked bad so it's not a complete waste of 10 bucks I guess.
My firebird book tells me to take it to a qualified tech and the wiring diagrams are next to useless. However my Grand Am book is more helpfull, twisted my mind a bit since i don't quite understand whats going on in those diagnostics. That book is telling me to replace the distributor. The distributor is rather pricy, and i'm not sure thats my problem, i just can't see how.
The ECM is probably good, it keeps flashing a 12
The ignition module, I cleaned up the grounds on it. I haven't had it tested, but it's been my experience those don't just die, you get a weaker spark as the engine gets hotter and it backfires if you get mad and floor it (I blew up a muffler on a 2.8 olds with a bad module, it was great everyone ran like it was terrorist attack, it was very very loud). The parts car ran OK (even with blown maf fuse) before I gutted it.
I think my problem is wiring related. There is something i did mess with, and its gonna be hard to explain. Little clues tell me I'm not the first person with this problem on this engine. There was this wire that someone had going from the fusebox to a thick red wire on the engine harness (it has a clip on it if that helps) and there was another wire attached to a pin on a relay(the one that says 5/10min what is that anyway?, it is/was disconnected)and that wire wasn't connected to anything, it looked like it used to be a ground (it ran while that was disconnected). Any how I xnayed both wires, and took the red one and put that directly to the power distribution node. The inside electronics worked oddly without it connected to power (interior worked, no dash lights, radio illuminated but didn't show the time or radio station).
Anybody know what that was all about, I've seen that relay bypassed on other cars. How do you do that and why? Right now thats my prime suspect but I took that apart 4 month ago and can't remember exactly how it was.
Oil pressure sender? I lost the bolt for it and grabbed one from a camaro. shot in the dark, but can it be bypassed. I know the car not supposed to start with no oil, but will it turn over? Oh word of advise.. put that on before you put the engine in..I had to customize a bit.
I'm at a dead end here. I'm really getting unhappy about turning the car over and not starting. I spent some coin on that rebuild, especially the heads.
To be clear I'm hoping someone will tell me about that relay, and maybe some trouble shooting suggestions.
hmmm what would superman do?
TGO Supporter
Joined: Sep 2000
Posts: 6,775
Likes: 27
From: So.west IN
Car: 87 Formula/ 00 Xtreme
Engine: TPI 305/ v6
Transmission: struggling t-5/ 4l60E
Axle/Gears: 3.08/ 3.23
I don't know much about the v-6s but they can't be that much different.
Here's an excerpt on testing ignition from on eof my handy-dandy F.I. books.
If there was no spark from the spark plug wire, the 2nd step is to probe the negative terminal of the ignition coil with a test light. If your not sure which side is negative, then insert it first on one side and crank the engine, then insert it on the other side. One side of the coil should have a steady supply of switched ignition voltage while the other side should flash on & off as the engine is cranked. If neither has power, then you have an open wire in the voltage supply to the coil. If both sides have steady power, then the problem is the primary ignition's control of the coil.
Hopefully that's a start (no pun intented
)
------------------
"Always do sober what you said you'd do drunk. That will teach
you to keep your mouth shut."
Here's an excerpt on testing ignition from on eof my handy-dandy F.I. books.
If there was no spark from the spark plug wire, the 2nd step is to probe the negative terminal of the ignition coil with a test light. If your not sure which side is negative, then insert it first on one side and crank the engine, then insert it on the other side. One side of the coil should have a steady supply of switched ignition voltage while the other side should flash on & off as the engine is cranked. If neither has power, then you have an open wire in the voltage supply to the coil. If both sides have steady power, then the problem is the primary ignition's control of the coil.
Hopefully that's a start (no pun intented
)------------------
- my Formula Homepage
- Collision P/Ns & Diagrams (Nearly complete now!)
"Always do sober what you said you'd do drunk. That will teach
you to keep your mouth shut."
I solved it -A bad connector- on the two wire piece from the ignition coil to distributor ign module. BUT
still no start, but a few rumbles. Distributor out 180 deg.
still no start, but a few rumbles. Distributor out 180 deg.
Last edited by Blade3001; Mar 11, 2004 at 11:29 PM.
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