LT1 Troubles
Thread Starter
Instructor
Joined: Jun 2016
Posts: 213
Likes: 59
From: North Augusta, South Carolina
LT1 Troubles
I have a 1992 Corvette LT1 with 127k miles thats been giving me some trouble. The car shuts off randomly at idle, and while driving the car, some times it sounds like the car literally farts (for lack of better words) out the exhaust; smells rich when it does this and makes your eyes burn.
What I've replaced in the past 3 months:
-Optispark: MSD unit
-TPS : AC-Delco
-Intake Air Temp Sensor
-New Computer
-Plugs and wires and the coil wire
-Fuel Filter
*Everything I have replaced was tested prior to replacing and every new sensor was checked to make sure it was in spec of the FSM*
Fuel Pressure is fine and the Fuel Pressure Regulator is fine as well.
The only thing that is left related to ignition is the Ignition Control Module and the Coil. Don't think the symptoms I'm having is pointing towards that. I'm also getting no codes. At this point I'm stuck scratching my head trying to figure out the problem.
Thanks for reading and any help is greatly appreciated!
What I've replaced in the past 3 months:
-Optispark: MSD unit
-TPS : AC-Delco
-Intake Air Temp Sensor
-New Computer
-Plugs and wires and the coil wire
-Fuel Filter
*Everything I have replaced was tested prior to replacing and every new sensor was checked to make sure it was in spec of the FSM*
Fuel Pressure is fine and the Fuel Pressure Regulator is fine as well.
The only thing that is left related to ignition is the Ignition Control Module and the Coil. Don't think the symptoms I'm having is pointing towards that. I'm also getting no codes. At this point I'm stuck scratching my head trying to figure out the problem.
Thanks for reading and any help is greatly appreciated!
Thread Starter
Instructor
Joined: Jun 2016
Posts: 213
Likes: 59
From: North Augusta, South Carolina
I haven't had the coil or ICM test. The original opti failed before I replaced it with the MSD and it doesn't act like the old one did when it was bad. As far as the cool and ICM goes, would I see much of drivability issues or is it more of once it's bad the car doesn't run. Would o2's cause the car to randomly stall? I've been talking to a local shop and they mention that the cats could be clogging. Not sure if that would cause make the car stall though. Thanks!
Race Director
Joined: Sep 2001
Posts: 14,623
Likes: 748
From: NEwhere Ohio
the 92-93 speed density cars are seriously affected by a bad o2
they will run so rich and foul the spark plugs (and cats if you dont correct the problem qui k).
eventually it will leave you with a no-start situation whn plugs foul completely.
i would plan on replacing o2's and spark plugs . may want to check and see if they are carbon fouled.
what kind of spark plugs? if they are fancy platinum or iridium they will foul quicker due to smaller tips vs. plain copper
i had this exact problem on my 93 in 2001.
it sounds like you are likely correct in thinking the msd opti is not the cause of these problems - given that you have had experience with a bad optispark and know what to expect.
this said, i hope you added a custom vent (like 95-96 units) to your msd opti or you will have to replace it sooner again.
they will run so rich and foul the spark plugs (and cats if you dont correct the problem qui k).
eventually it will leave you with a no-start situation whn plugs foul completely.
i would plan on replacing o2's and spark plugs . may want to check and see if they are carbon fouled.
what kind of spark plugs? if they are fancy platinum or iridium they will foul quicker due to smaller tips vs. plain copper
i had this exact problem on my 93 in 2001.
it sounds like you are likely correct in thinking the msd opti is not the cause of these problems - given that you have had experience with a bad optispark and know what to expect.
this said, i hope you added a custom vent (like 95-96 units) to your msd opti or you will have to replace it sooner again.
Last edited by dizwiz24; Jun 13, 2016 at 12:39 PM.
Thread Starter
Instructor
Joined: Jun 2016
Posts: 213
Likes: 59
From: North Augusta, South Carolina
Thanks for the input! I replaced the wires and plugs about 800 miles ago. Put double platinum Bosch plugs in. When I get a chance I'll pull the plugs and check them. I'm not sure the condition of the o2 sensors. I have access to a car lift when I'm not living at school so I'll take a weekend and put it on a lift and check all that out.
Thread Starter
Instructor
Joined: Jun 2016
Posts: 213
Likes: 59
From: North Augusta, South Carolina
the 92-93 speed density cars are seriously affected by a bad o2
they will run so rich and foul the spark plugs (and cats if you dont correct the problem qui k).
eventually it will leave you with a no-start situation whn plugs foul completely.
i would plan on replacing o2's and spark plugs . may want to check and see if they are carbon fouled.
what kind of spark plugs? if they are fancy platinum or iridium they will foul quicker due to smaller tips vs. plain copper
i had this exact problem on my 93 in 2001.
it sounds like you are likely correct in thinking the msd opti is not the cause of these problems - given that you have had experience with a bad optispark and know what to expect.
this said, i hope you added a custom vent (like 95-96 units) to your msd opti or you will have to replace it sooner again.
they will run so rich and foul the spark plugs (and cats if you dont correct the problem qui k).
eventually it will leave you with a no-start situation whn plugs foul completely.
i would plan on replacing o2's and spark plugs . may want to check and see if they are carbon fouled.
what kind of spark plugs? if they are fancy platinum or iridium they will foul quicker due to smaller tips vs. plain copper
i had this exact problem on my 93 in 2001.
it sounds like you are likely correct in thinking the msd opti is not the cause of these problems - given that you have had experience with a bad optispark and know what to expect.
this said, i hope you added a custom vent (like 95-96 units) to your msd opti or you will have to replace it sooner again.
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Thread Starter
Instructor
Joined: Jun 2016
Posts: 213
Likes: 59
From: North Augusta, South Carolina
I did not check the cats only because I need to drive the car tomorrow to Daytona from south Carolina and I didn't want to remove them and damage a bolt (which will mostly melt happen with the age of the car and my luck haha). Can the cat be checked while on the car
Race Director
Joined: Mar 2015
Posts: 15,926
Likes: 578
If it was me I would spray the bolts with PB blaster a few times and heat them. Then smack the cat and listen for rattles and hope it breaks some clog loose then run it hard to Florida repeat and run it back.