85 sudden no-start-ignition module?
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Pro
Joined: Oct 2005
Posts: 541
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From: Freeport FL
85 sudden no-start-ignition module?
This concerns my 1985 (ZZ4 repower, but stock engine management):
I took it out last night to the sub shop about 5 miles away. After eating I went out and the car would not start. It turns over fine and seems to hit during the cranking cycle, but dies immediately after letting the key back out of the start position. It seems to be getting spark when the key is in the start position, but not when I release it to the run position. Kind of like in the old days when cars used 2 separate circuits for ignition voltage and you could lose the run circuit voltage? There is plenty of gas in the car. This car also did this a month ago and finally started (and ran fine since) after I went and got a gallon of gas and put it in the tank, but now I am thinking it wasn’t gas related then either. The only thing I know of that makes a (semi)modern car just suddenly not start like this is the ignition module. Anyone concur? And um…..where is the thing?
For the record the plugs, cap, rotor and coil, and wires are only about a year old, and when the car was running, it was running strong. Plenty of fuel pressure at the shrader valve.
I took it out last night to the sub shop about 5 miles away. After eating I went out and the car would not start. It turns over fine and seems to hit during the cranking cycle, but dies immediately after letting the key back out of the start position. It seems to be getting spark when the key is in the start position, but not when I release it to the run position. Kind of like in the old days when cars used 2 separate circuits for ignition voltage and you could lose the run circuit voltage? There is plenty of gas in the car. This car also did this a month ago and finally started (and ran fine since) after I went and got a gallon of gas and put it in the tank, but now I am thinking it wasn’t gas related then either. The only thing I know of that makes a (semi)modern car just suddenly not start like this is the ignition module. Anyone concur? And um…..where is the thing?
For the record the plugs, cap, rotor and coil, and wires are only about a year old, and when the car was running, it was running strong. Plenty of fuel pressure at the shrader valve.
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Joined: Oct 2007
Posts: 82
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From: California
It does sound exactly like the old days with a circuit to the coil when cranking and a separate circuit with the key in the "Run" position. I'd check the voltage to the ignition control module and/or coil with the key in the "Run" position.
I don't know about your vintage but, I do knowthat GM ignition switches are not the best in the world and have been known to drop dead in the start and/or run modes without warning.
Hope this helps.
Norm.
I don't know about your vintage but, I do knowthat GM ignition switches are not the best in the world and have been known to drop dead in the start and/or run modes without warning.
Hope this helps.
Norm.
Race Director
Joined: Sep 2005
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Likes: 1
St. Jude Donor '07
This is odd...
Quick 'what the heck' ideas:
Any codes?
Unplug the MAF and try again.
It also sounds flooded. How long does it hold fuel pressure after you prime it?
Un plug your fuel pump fuse and remove the MAF & accordion. Crank it for a few seconds. Spray some starter fluid into the plenum. See if it starts. No start could mean ignition. Start could mean fuel.
Quick 'what the heck' ideas:
Any codes?
Unplug the MAF and try again.
It also sounds flooded. How long does it hold fuel pressure after you prime it?
Un plug your fuel pump fuse and remove the MAF & accordion. Crank it for a few seconds. Spray some starter fluid into the plenum. See if it starts. No start could mean ignition. Start could mean fuel.
Thread Starter
Pro
Joined: Oct 2005
Posts: 541
Likes: 1
From: Freeport FL
So I go out today...(car towed home last night) and before touching anything, I crank the car and it starts right up. Nice huh?
So I took the ignition module out and took it down to be tested. It seemed to test OK, except on 2 tries, but the guy thought his connections were loose on the test machine. Anyways, I went ahead and got a new module ($20) and a new condenser ( I was surprised to see that in there, but apparently it is there for noise purposes only (but what would happen if that failed?))
Ill put them in tomorrow, and hopefully this will solve the problem..and I wont have some ghost living in there for the next 6 months!
So I took the ignition module out and took it down to be tested. It seemed to test OK, except on 2 tries, but the guy thought his connections were loose on the test machine. Anyways, I went ahead and got a new module ($20) and a new condenser ( I was surprised to see that in there, but apparently it is there for noise purposes only (but what would happen if that failed?))
Ill put them in tomorrow, and hopefully this will solve the problem..and I wont have some ghost living in there for the next 6 months!
