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I have a 1993 corvette lt1. Bought it a month ago with the check engine light on throwing code 43 for which I the driver side knock sensor was broke. Replaced it and light went out and car ran like a beast! Since that it’s been running up to 230 degrees when I stop in traffic and it didn’t do that before. Found out fan motor went out so I replaced the motor and fuse and fan comes on at 228 degrees but again, it didn’t get that hot before I changed knock sensor. 210 was the highest it got to. 3 days later I went to pull out somewhere and when I pushed the gas, it died and every time I tried to crank it back up, it would catch, and go right back dead so I had to tow it home. I’ve replaced the fuel filter and it drove fine for a day and did it again. Replaced fuel filter, plugs and wires then and it drove fine for about 45 min then it died and got it goin to limp to work. Driving home just now, it was fine for 5 min then it died. Got it goin and it started bucking like fuel pump was goin out. It wouldn’t let me push the gas hardly at all without it cutting out, and now it’s throwing codes 22, 34, 43, and 66. Any help or advice would be great cuz I have no clue and this is my 1st vette so I don’t know a whole lot!
Be warned, this info was pulled from 1992 service manual. Hope these help. Id look into the throttle position sensor first if it were me.
These are ECM codes, correct? Start with 22 throttle position sensor signal voltage low. Plenty of info on here about checking, adjusting, if you dont have the manual.
34 is MAP signal voltage low (high vacuum) but may be set if throttle position is not jiving with MAP feedback.
43 is electronic spark circuit fault, will be set when 1)one knock sensor open 2)both sensors open 3) both sensors grounded.
The 66 is A/C pressure sensor circuit, (not critical at the moment).
Thanks!! Yea they r ecm codes. Im goin Friday afternoon to get the TPS and MAP sensor. Just gonna knock those 2 out 1st. My Vette is parked til then so I’ll update when I get them in! Again, thanks so much!
Based on your description it might be your ECM. My '92 had similar symptoms that were intermittent like that. I sent it out to be rebuilt and it has been fine since.
Having a 93 since new check to see if Opti has been replaced Also cap&rotor water pump. Forget these codes you have a ob! system and this year will spit codes out and drive you crazy. If you have a record of maintance that will help! These C4 are a hand full any questions?
Yea Opti has been replaced, along with water pump and thermostat (180 degree). I’ve thought that it could be the ecm but im gonna try the “smaller/cheaper” stuff 1st and go from there. It does have 215k on it, so I’m doin process of elimination right now! Hopefully when all is said and done, it should b a good runnin car!
I have a 1993 corvette lt1. Bought it a month ago with the check engine light on throwing code 43 for which I the driver side knock sensor was broke. Replaced it and light went out and car ran like a beast! Since that it’s been running up to 230 degrees when I stop in traffic and it didn’t do that before. Found out fan motor went out so I replaced the motor and fuse and fan comes on at 228 degrees but again, it didn’t get that hot before I changed knock sensor. 210 was the highest it got to. 3 days later I went to pull out somewhere and when I pushed the gas, it died and every time I tried to crank it back up, it would catch, and go right back dead so I had to tow it home. I’ve replaced the fuel filter and it drove fine for a day and did it again. Replaced fuel filter, plugs and wires then and it drove fine for about 45 min then it died and got it goin to limp to work. Driving home just now, it was fine for 5 min then it died. Got it goin and it started bucking like fuel pump was goin out. It wouldn’t let me push the gas hardly at all without it cutting out, and now it’s throwing codes 22, 34, 43, and 66. Any help or advice would be great cuz I have no clue and this is my 1st vette so I don’t know a whole lot!
230 in traffic is normal with the AC off. Considering you have an AC fault it likely isn't running, hence the temps climbing.
The computer has two modes, one when cold and another when warmed up. I'll second that you are likely to have a faulty computer. It's common behavior to see cold start run fine then warm do all kinds of crazy stuff with a bad computer.
i got my sensors put in today, but when I went to start my car, nothing happened. I turn the key and all the lights come on like normal, fuel pump primes, fans gear up, and when I turn to crank, absolutely nothing happens! I plugged my obd1 scanner in and now all I’m getting is code 12. Is this ecm?
Also, my Service ASR light is on with the SES light now
Last edited by Seancarnes89; Apr 20, 2018 at 08:14 PM.
No codes on the scanner? Hard to think there are no codes. Did you just outright replace the TPS? With the throttle completely closed, can you see the TPS voltage on your scanner?
when you say the fans gear up. You mean the cooling fans come on when you turn to the key to run position?
oh, and did you try starting it with both keys? Just making sure the pass key wasn’t acting up.
Last edited by AJT84; Apr 21, 2018 at 09:48 AM.
Reason: More questions.
22 Throttle Position Sensor Circuit Signal Voltage Low
34 MAP Sensor Signal Voltage Low, High Vacuum
43 Knock Sensor (KS) Circuit
66 Engine Power Switch Circuit (Signal Voltage High or Low)
Since you've got a scanner, I'd start with the OBD System Check. (6E3-A-17) in the FSM)
93 corvette codes, 22, 34, 43, 66
