Cannot fix my lt1
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Instructor
Joined: Apr 2010
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From: Dalton Georgia
Cannot fix my lt1
I have a 1994 corvette that I cannot fix. Car runs fine when cold but once it warms up it runs rough and floods horribly. It was killing o2 sensors till I got a gm original but now no ses light just rough running and flooding. I have replaced the ecm, opti, coil, egr valve, egr control, air pump, cleaned the check valves, removed cats, ran seafoam thru it. No matter what I do the Gremlins come back. I am about convinced the car is unfixable.
Melting Slicks
Joined: Oct 2007
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From: KB7TIF Ville NV
I have a 1994 corvette that I cannot fix. Car runs fine when cold but once it warms up it runs rough and floods horribly. It was killing o2 sensors till I got a gm original but now no ses light just rough running and flooding. I have replaced the ecm, opti, coil, egr valve, egr control, air pump, cleaned the check valves, removed cats, ran seafoam thru it. No matter what I do the Gremlins come back. I am about convinced the car is unfixable.
Its pry a sensor as it goes into closed loop it runs like S%$#. its really not all that bad. hows the mass airflow sensor. Any codes in the computer??
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Instructor
Joined: Apr 2010
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From: Dalton Georgia
No computer codes... It mainly floods the passenger side of the block though.... I have noticed that my digital temp is always about 15-20 degrees cooler than my analog guages temp. Before I swapped the o2 out it was throwing h64
Melting Slicks
Joined: Oct 2007
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From: KB7TIF Ville NV
I will be thinking about your prob
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Instructor
Joined: Apr 2010
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From: Dalton Georgia
yes i removed the post cat sensor an put it in on the drivers side which has never failed. I put the drivers side sensor in on the passeneger side and the replacement sensor into the post cat hole.
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Joined: Mar 2001
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From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
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St. Jude Donor '12
I gotta finish putting my 383 together this weekend.
Let me look at a calendar
yea, I think I have some time on the 28th - PM me if you want to come over and we can look at it together. I'm near Stone Mtn, do you have a factory service manual for your year?
James
Let me look at a calendar
yea, I think I have some time on the 28th - PM me if you want to come over and we can look at it together. I'm near Stone Mtn, do you have a factory service manual for your year?
James
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From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
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St. Jude Donor '12
there is a cable from the opti to a connector on the passenger intake.
That is the ECM connection. In the past week I've seen the troubleshooting guide posted maybe three times. Do a search. You'll need a $5.00 volt meter to do some of the tests.
its a good chance there is an issue in the signal paths from the opti to the ECM which then triggers the ICM to fire the coil and give you spark.
If you are going to keep the car, get thee a FSM for your model year. It will save you time, money and aggrivation in the long run.
If I had to guess the 4 wire harness from the opti to the connector is fubar in some way.
Only testing it would show the real cause. See if you can find that post with the troubleshooting. If you can't find it I'll look when I get home
That is the ECM connection. In the past week I've seen the troubleshooting guide posted maybe three times. Do a search. You'll need a $5.00 volt meter to do some of the tests.
its a good chance there is an issue in the signal paths from the opti to the ECM which then triggers the ICM to fire the coil and give you spark.
If you are going to keep the car, get thee a FSM for your model year. It will save you time, money and aggrivation in the long run.
If I had to guess the 4 wire harness from the opti to the connector is fubar in some way.
Only testing it would show the real cause. See if you can find that post with the troubleshooting. If you can't find it I'll look when I get home
Instructor
Joined: Dec 2009
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From: New Jersey
You may have a problem with the water pump temp sensor.
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From: Maryville Tn
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St. Jude Donor '09 thru '23
NCM Sinkhole Donor
Check your ignition control module (it's mounted on a heat sink on the right cylinder head). When my '93 started acting up when it was hot, the ICM was the problem. All of the module grease was almost gone off the back of it.
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Instructor
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From: Dalton Georgia
Sorry for the delay. To add insult to injury I had a minor accident in it yesterday. It just damaged the drivers door is all. Shop says it will be a couple of weeks before I get it back. Thank all of you for your imput. I now have a few more things to check on the car to see if i can locate the problem.
Thread Starter
Instructor
Joined: Apr 2010
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From: Dalton Georgia
Something I have noticed is if i change out the o2 sensors. it runs fine for 50-500 miles then it keeps leaning the passenger side out till the problems start all over again. and the problem comes and goes too
Instructor
Joined: Nov 2009
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From: Spring Texas
Had similar problem with 1995 LT-1. I had replaced the MAP Sensor as they age and fail, car will run rich. The AC Delco store on the WEB sent me the wrong Map Sensor. I spent months chasing the problem. Finally went to the local AC Delco shop and talked to them. For 95 there are 2 Map Sensors for the Vin P LT-1. The correct one is ACD 273-3205, GM# 19106672. Solved my problem. I also had changed everything from O-2 sensors to Check Valves. A B-W CTS Coolant Temp Sensor was also giving erroneous readings much like the differnce you see between the digital temp (CTS) and analog temp. Replaced with ACD 213-4396, GM#19187357. Correct Check Valaves are ACD 214-419, GM#22040805. Since theere is considerable interaction between the MAP Sensor and the EGR Valve ACD 214-5083, GM#19210658, I replaced it. This emission control system is one of the most critical computer functions in the LT-1 series and from my experience does not work well with Borg-Warner sensors. Good luck.
