ignition cutting out
Thread Starter
Heel & Toe
Joined: Sep 2005
Posts: 15
Likes: 0
From: Sacramento CA
ignition cutting out
Help! Bought a '92 LT1 6-speed two weeks ago. About ten minutes from the guy's house, the ignition seemed to cut out and the motor fell on its face. At the same time, it was backfiring. The revs dropped down to about 1000 and then was idling fine. Until the motor fired back up at 1000, hitting the gas did nothing at all which seems to me that the ignition was off. The motor never did die completely; it idled just fine. I could drive for about 20 seconds and then it would happen again.
The car was pretty hot at the time and I thought maybe it was overheating. I shut it off and let it sit for about 1/2 hour to cool off. The coolant looked like mud. After it cooled off, it ran fine again and I was able to get home about 7 minutes away. I flushed the coolant last weekend and then the water pump started leaking. It didn't look like it had been leaking until then. I replaced the water pump, plugs, wires, thermostat and rad cap this weekend. I just went for a drive and the same problem occurred - after about ten minutes of driving the engine died and would only idle. Once it is idling OK, I can give it gas and hold it at a steady RPM for about 5 seconds until the motor cuts out again. Any ideas? Is this how the Optisparks go out?
The car was pretty hot at the time and I thought maybe it was overheating. I shut it off and let it sit for about 1/2 hour to cool off. The coolant looked like mud. After it cooled off, it ran fine again and I was able to get home about 7 minutes away. I flushed the coolant last weekend and then the water pump started leaking. It didn't look like it had been leaking until then. I replaced the water pump, plugs, wires, thermostat and rad cap this weekend. I just went for a drive and the same problem occurred - after about ten minutes of driving the engine died and would only idle. Once it is idling OK, I can give it gas and hold it at a steady RPM for about 5 seconds until the motor cuts out again. Any ideas? Is this how the Optisparks go out?
Drifting
Joined: Mar 2005
Posts: 1,923
Likes: 0
From: GA
I bet the guy that sold you the car put some kind of leak stop in the cooling system because the pump was leaking/shot and he just wanted to sell it. and if it were leaking before, it probably took out the opti..
One "cheaper" thing you could try is to take it to a dealer/speciality shop and have them diagnose the ignition system. It may end up being the ignition module...keep your fingers crossed.
Oh...flush out that cooling system throughly and get all of the "mud" out...run the heater while flushing.
One "cheaper" thing you could try is to take it to a dealer/speciality shop and have them diagnose the ignition system. It may end up being the ignition module...keep your fingers crossed.
Oh...flush out that cooling system throughly and get all of the "mud" out...run the heater while flushing.
Thread Starter
Heel & Toe
Joined: Sep 2005
Posts: 15
Likes: 0
From: Sacramento CA
No, the engine was not washed. In fact, it is still a little greasy. The water pump didn't have any telltale signs (stains) of leakage from the past. It didn't start until I used Prestone Heavy Duty Cleaner (2-part powder)- which is the only thing that works from my past experience. The PO had just smogged it the day I got it with no problem.
I scanned it last night; no problem codes at all! Just 12...12...12...12...12. If it's ignition related shouldn't there be some faults? The PO did have a coil problem recently and the dealership replaced it. Would a faulty coil or coil module cause this running problem. I'm tempted to just throw an MSD coil on it for the hell of it. Thanks guys.
I scanned it last night; no problem codes at all! Just 12...12...12...12...12. If it's ignition related shouldn't there be some faults? The PO did have a coil problem recently and the dealership replaced it. Would a faulty coil or coil module cause this running problem. I'm tempted to just throw an MSD coil on it for the hell of it. Thanks guys.
Thread Starter
Heel & Toe
Joined: Sep 2005
Posts: 15
Likes: 0
From: Sacramento CA
anybody, anybody?
Come on. None of you guys has had this same problem? It seems like it would be a common symptom of either the Optispark or coil module going out. I'm getting nowhere. I replaced the coil with an MSD Blaster hoping it would be a cheap simple fix - no change. I didn't try a new coil module. The engine is still shutting down when it gets hot (230 F) and you hold a steady rpm. No damn error codes!
I suspected maybe the fuel filter was clogged and after running for a while not letting enough fuel through - the pressure looks good though even when the motor is shutting down.
The ignition is definitely shutting down. The tach drops right to zero as soon as the problem occurs. The tach drops before the engine revs actually come down which tells me that the ignition is shutting off. Today, when I intentionally let it heat up and held the revs at around 3000 to get it to shut down, it would diesel until I turned off the key. It will fire right back up though and idle just fine.
Nobody has experienced the same symptoms? Thanks for any advice.
I suspected maybe the fuel filter was clogged and after running for a while not letting enough fuel through - the pressure looks good though even when the motor is shutting down.
The ignition is definitely shutting down. The tach drops right to zero as soon as the problem occurs. The tach drops before the engine revs actually come down which tells me that the ignition is shutting off. Today, when I intentionally let it heat up and held the revs at around 3000 to get it to shut down, it would diesel until I turned off the key. It will fire right back up though and idle just fine.
Nobody has experienced the same symptoms? Thanks for any advice.
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Originally Posted by TroyDest
The water pump didn't have any telltale signs (stains) of leakage from the past. It didn't start until I used Prestone Heavy Duty Cleaner (2-part powder)- which is the only thing that works from my past experience. .
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Thread Starter
Heel & Toe
Joined: Sep 2005
Posts: 15
Likes: 0
From: Sacramento CA
problem gone
BINGO. Problem has gone away with replacement of Ignition Control Module. I just drove it twice for about 1/2 hour each with no ignition problems and I was hammering it. None of the other items I replaced had any effect (fuel filter, plugs, wires, coil, knock sensors, coolant temperature sensor).
I did find a wire unplugged from the transmission when I was under there replacing the knock sensors. It was a short pigtail coming from a solenoid that screws into the rear left side of the ZF 6-speed. I went ahead and plugged it in; I really doubt it had anything to do with my ignition problem though. I don't know what that particular solenoid does. Of course, the POS Chilton is no help.
I guess I'll go ahead and start driving my "new" car now and register it in my name!
I did find a wire unplugged from the transmission when I was under there replacing the knock sensors. It was a short pigtail coming from a solenoid that screws into the rear left side of the ZF 6-speed. I went ahead and plugged it in; I really doubt it had anything to do with my ignition problem though. I don't know what that particular solenoid does. Of course, the POS Chilton is no help.
I guess I'll go ahead and start driving my "new" car now and register it in my name!
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
CAGS plug
Originally Posted by TroyDest
BINGO. I did find a wire unplugged from the transmission when I was under there replacing the knock sensors. It was a short pigtail coming from a solenoid that screws into the rear left side of the ZF 6-speed. I went ahead and plugged it in; I really doubt it had anything to do with my ignition problem though. I don't know what that particular solenoid does. Of course, the POS Chilton is no help.
I presume now if you go easy on the throttle when taking off, the trans is now preventing you from shifting into 2nd.
If you want to disconnect it again, I would suggest instead of just leaving it disconnected, risking plug corrosion and possible DTC's, installing the CAGS bypass plug, available from Ecklers via this link: http://www.ecklers.com/product.asp?p...A7K4URWN8V9H1E
Hope this helps..
