Good luck.
LT-1 ignition experts
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,539
Likes: 63
From: new ulm mn
LT-1 ignition experts
My '95 auto has started to miss intermittently. It will be running fine and just like a switch was pulled, it starts to miss badly. It will miss for a few miles and then just as quickly stop. It's starting to miss more and more. My guess is ignition. Gas would be more of a constant thing. Any thoughts? Thanks.
Racer
Joined: Jan 2005
Posts: 418
Likes: 45
From: Houston Texas
I have a 96 stock LT1 auto 115k and mine is starting to miss also, but only for a second or two. You're probably ahead of me on the trail, so I would be interested in learning the cause and solution. The few times mine misses seems to be when I lightly get back on the throttle, like after coasting a bit then attempting to maintain speed.
My first reaction is "Opti" based on all the horror stories on the forum, but we have the improved Opti, and any distributor that goes over 100k without maintenance can't be all that bad!
Also, I don't have any violent reaction when the miss comes and goes; meaning with a carb'd car, a miss in the ingnition gives you a jerking reaction when the unburned gas is re-ignited. The smooth reaction of my miss makes me think it might be related to the injectors and/or computer grounds.
I'm also wondering if it might be vacuum related since I don't seem to feel it under steady throttle.
Keep us posted and l personally would like to know how it turns out.
My first reaction is "Opti" based on all the horror stories on the forum, but we have the improved Opti, and any distributor that goes over 100k without maintenance can't be all that bad!
Also, I don't have any violent reaction when the miss comes and goes; meaning with a carb'd car, a miss in the ingnition gives you a jerking reaction when the unburned gas is re-ignited. The smooth reaction of my miss makes me think it might be related to the injectors and/or computer grounds.
I'm also wondering if it might be vacuum related since I don't seem to feel it under steady throttle.
Keep us posted and l personally would like to know how it turns out.
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 59
From: Fremont Oh
prolly opti...It will get to a pont if you romp on it it will have a high speed miss and then you'll probably get a code stating that hi or lo resolution error...
That had been my experience...
Mo
Advanced
Joined: May 2005
Posts: 87
Likes: 0
From: knox. tn.
Pull a spark plug from each side see if one side is running richer than the other.I just went through the same thing & everyone said optispark.So before I spent alot of money on the opti I went & had the car diagnostically tested for 60.00.Problem had nothing to do with opti , it was a 50.00 oxygen senser & took 5 min. to change not 9 or 10 hours.Mine pulled a lean code & a multiple cylinder missfire code.GOOD LUCK
Melting Slicks
Joined: Jul 2003
Posts: 3,226
Likes: 49
From: Pomfret, CT
Finalist 2020 C4 of the Year - Unmodified
Originally Posted by LT4-Z51
I just went through the same thing & everyone said optispark.So before I spent alot of money on the opti I went & had the car diagnostically tested
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Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
I am not so convinced the miss is caused by the opti. If it was an opti related miss, it would be associated with a wondering idle and be isolated to an higher RPM. Also, the miss would be consistant.
My guess? A bad fuel filter or the coil wire is grounding to the engine/waterpump.
My guess? A bad fuel filter or the coil wire is grounding to the engine/waterpump.
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,539
Likes: 63
From: new ulm mn
Okay, I assumed it was bad gas and put injector cleaner in the tank, fresh gas, and new fuel filter and drove about 100 miles. Still misses badly but now have a bad knock on the front end of the engine at low idle. Any ideas? No codes.
Last edited by loflite; Oct 6, 2005 at 11:46 PM.
Advanced
Joined: May 2005
Posts: 87
Likes: 0
From: knox. tn.
Quite being stubborn & go have it diagnosed or spend 1500.00 dollers replacing this part then that part just to find out that each part doesn't fix the problem.Like my last post I went through the same thing mine even started knocking also it was the o2 sensor & didn't throw a o2 sensor code , remember if the lt1 is like the lt4 you have 2 sensors in front of the cat & 2 behind it.If you just want to throw money away I'll send you my pay-pal account ### GOOD LUCK
Team Owner
Joined: Oct 2000
Posts: 96,443
Likes: 9
From: Fort Knox, KY
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Open your hood at night or in a darkened garage and see if you see electrical arcing off the plug wires. If not, you've probably got the Optispark Blues. It's an inevitable LT-1/LT-4 issue.
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
check opti vent lines
Might it be damaged opti-spark vent lines causing intermittent moisture in the opti?
See the following link about a campaign for the 95's:
CAC 95 recall - opti vent line]CAC 95 recall
See the following link about a campaign for the 95's:
CAC 95 recall - opti vent line]CAC 95 recall
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
Originally Posted by loflite
Finally got the car into the garage for diagnosis. Bad news. Broken valve springs on #2 and #4. One exhaust and one intake. 
Did you hurt anything else with the broken springs?
Are you going to replace them with behives or something a little more stout than the behives?
Mike
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,539
Likes: 63
From: new ulm mn
The valve springs are Manly springs put in by Doug Rippie. This is the second failure with these springs. Last time DRM covered the failure and installed new springs. I've got a call into Rippie now. Both times the failures happened cruising down the highway at about 1700 RPM. the car is not really driven very hard. Maybe that's the problem! I need to drive it harder.
Le Mans Master
Joined: Feb 1999
Posts: 9,919
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Originally Posted by loflite
The valve springs are Manly springs put in by Doug Rippie. This is the second failure with these springs. Last time DRM covered the failure and installed new springs. I've got a call into Rippie now. Both times the failures happened cruising down the highway at about 1700 RPM. the car is not really driven very hard. Maybe that's the problem! I need to drive it harder.