LT1 no-start, no ignition, no codes
LT1 no-start, no ignition, no codes Hi guys,
My son's '94 T/A had three incidents of dying on him. The first two times, the car would re-start after about 20 minutes. When running, the car runs great with no other symptoms. One of the times it died the engine was warmed up, but the other two times it was relatively cold, only driven a mile or two. When it dies, it has no spark. I replaced the ignition coil and module, but the car just died again. The car hasn't re-started since it died the last time, which was about two hours ago. It has not thrown any codes, which makes it extra hard to diagnose. When it was running (between dying incidents), I hooked up my scan tool and checked all the data. Everything was within the specs in the factory book. I put in a new Chandler lifetime Opti about a year and a half ago (but only about 2,000 miles).
One other thing is that the previous owner installed a Holley Annihilator ignition system (P/N 800-107, according to the receipt). I am able to see a box under the driver' side headlight that I'm pretty sure is it, but it is wrapped in aluminum foil, so I can't be sure, and I haven't taken things apart yet so I can get at it. I don't know if this thing might be able to cause the problem or not.
Any thoughts would be appreciated!
My son's '94 T/A had three incidents of dying on him. The first two times, the car would re-start after about 20 minutes. When running, the car runs great with no other symptoms. One of the times it died the engine was warmed up, but the other two times it was relatively cold, only driven a mile or two. When it dies, it has no spark. I replaced the ignition coil and module, but the car just died again. The car hasn't re-started since it died the last time, which was about two hours ago. It has not thrown any codes, which makes it extra hard to diagnose. When it was running (between dying incidents), I hooked up my scan tool and checked all the data. Everything was within the specs in the factory book. I put in a new Chandler lifetime Opti about a year and a half ago (but only about 2,000 miles).
One other thing is that the previous owner installed a Holley Annihilator ignition system (P/N 800-107, according to the receipt). I am able to see a box under the driver' side headlight that I'm pretty sure is it, but it is wrapped in aluminum foil, so I can't be sure, and I haven't taken things apart yet so I can get at it. I don't know if this thing might be able to cause the problem or not.
Any thoughts would be appreciated!
I've bypassed the Holley ignition, it's back to stock configuration, and I've still got the problem. I'm pulling the ignition switch now to have a look to see if there could be a problem there. That was a good thought. I hadn't thought of that. I don't think keys could be an issue here, though, since the switch is on top of the column. Still no codes! Perplexing. It started and drove about 1/2 mile this time, then stalled and hasn't started since.
I took out the ignition switch and disassembled it. It looked fine. Nevertheless, I'm going to Pep Boys to buy a new one. I think I've eliminated everything except the Opti, damn it! But why am I not getting any codes?
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Teching In
Joined: Oct 2007
Posts: 34
Likes: 0
From: Mount Airy, MD
Unhook the MAF and retest. Ive had some go out of range but not set the failure code in the pcm, Beyond that if it still wont start, pull the coil wire and have someone crank so you can check spark. If you have no spark, its time for some pinout testing. I'd bet your dropping voltage through the power buss inside the coil, but check for spark first, don't just slap a coil on.
Chris
Chris
OK. I think we need a review. When the problem happens there is NO SPARK (checked with my spark tester both at the coil wire and at a spark plug wire). The ignition coil, module and ignition switch have all been replaced. The biggest issue has been being able to diagnose it, since it is intermittent. By the time I'm ready to do some testing, it's running fine again. I've checked all connections, wiggled them with the engine running, checked for codes (NO CODES) and checked all data with my scan tool. I think the only thing left is the Opti, but experience of others would be helpful. I don't want my son to drive the car like this, since he will wind up stranded.
I have not checked to see if I'm getting voltage to the coil. I will do that. On the injector pulse, I don't have a noid light. I think my friend does, and maybe I can borrow it from him.
OK. I've checked the ICM harness. 11.5 volts at A and D, zero ohms at C (to ground). At B, I wasn't getting any switching signal at first, then I started getting a weak one (about .4V AC). So I plugged the module back in, and it started right up and ran perfectly for about 15 minutes, then it stalled again. Then I got 0 volts at B when cranking.
It sure seems like Opti or Opti harness to me. Thoughts?
It sure seems like Opti or Opti harness to me. Thoughts?
Last edited by 30th droptop; Feb 21, 2012 at 09:06 PM.
TECH Veteran
Joined: Dec 2008
Posts: 4,147
Likes: 62
From: Little Rock, AR
OK. I've checked the ICM harness. 11.5 volts at A and D, zero ohms at C (to ground). At B, I wasn't getting any switching signal at first, then I started getting a weak one (about .4V AC). So I plugged the module back in, and it started right up and ran perfectly for about 15 minutes, then it stalled again. Then I got 0 volts at B when cranking.
It sure seems like Opti or Opti harness to me. Thoughts?
It sure seems like Opti or Opti harness to me. Thoughts?
I was just looking back through the replies from you guys, wanting to make sure I'd covered all bases. Stuart4185: I have an M6, but I would think a problem with a clutch start switch would cause the engine to not crank at all. The problem I'm having is that the car stalls, then cranks but won't start. These weren't your symptoms, were they?
Thanks, Shbox, I will definitely do a continuity check on the signal wire between the PCM and the ICM and wiggle the hell out of it. I don't want to replace an Opti if I don't have to!
Launching!
Joined: Jan 2012
Posts: 211
Likes: 0
From: baltimore maryland
yes and no lol. i had compound problems. IAC valve had carbon build up and caused the car to stall at idle, the clutch switch made it worse as it wouldnt start about 25% of the times i tried it. and the resistor in the key also gave me hell for a few weeks. i was more just tossing ideas out that were out of the box but could cause problems you were describing.
yes and no lol. i had compound problems. IAC valve had carbon build up and caused the car to stall at idle, the clutch switch made it worse as it wouldnt start about 25% of the times i tried it. and the resistor in the key also gave me hell for a few weeks. i was more just tossing ideas out that were out of the box but could cause problems you were describing.
Now my next question is: Should I replace the timing chain/gears as long as I've got the Opti off? It's the original set, and the car's got 115K miles. It's been very well cared for, though (regular oil changes, etc.).
TECH Veteran
Joined: Dec 2008
Posts: 4,147
Likes: 62
From: Little Rock, AR
It depends on how much preventative maintenance you want to do. It is a bit more trouble to get the front cover off. You will have to lower the front of the oil pan. You also might consider whether you want to change any of the seals on the front of the cover.