C4 93 LT1 electrical gremlin
Thread Starter
7th Gear
Joined: Mar 2017
Posts: 7
Likes: 0
C4 93 LT1 electrical gremlin
I have a 93 corvette LT1 ( 62,000 miles ) within the last 3500 miles it has new AC compresssor and a/c
clutch , IAC , Coil , optispark , wires, plugs, fuel pressure reg , sending unit , fuel injectors , fuel filter , air filter , converted to R134 , transducer, alternator and regulator , battery , O2 sensors , TPS , MAP and ATS.
When the AC compressor and CC system is turned OFF the voltage jumps a few times a second ( between 12.00 and 14.5 volts ) and the car runs rough at start up on or off. Once the CC kicks in and the car is at operating temperature it runs smooth and can be driven with out noticing anything. Car has full power and runs fine. With the AC/CC off then it will run fine at speed but rough idle. No one can figure this out . Really annoying. HELP !!!!! any suggestions ???
clutch , IAC , Coil , optispark , wires, plugs, fuel pressure reg , sending unit , fuel injectors , fuel filter , air filter , converted to R134 , transducer, alternator and regulator , battery , O2 sensors , TPS , MAP and ATS. When the AC compressor and CC system is turned OFF the voltage jumps a few times a second ( between 12.00 and 14.5 volts ) and the car runs rough at start up on or off. Once the CC kicks in and the car is at operating temperature it runs smooth and can be driven with out noticing anything. Car has full power and runs fine. With the AC/CC off then it will run fine at speed but rough idle. No one can figure this out . Really annoying. HELP !!!!! any suggestions ???
Burning Brakes
Joined: Apr 2009
Posts: 1,185
Likes: 33
From: Charlotte Michigan
Poor grounds and possible shorts. Maybe in several locations. Have you pulled codes? Use FSM to diagnose problem rather than replace components, it would save money!
Last edited by scotth48; May 8, 2017 at 09:16 PM. Reason: Added words
Thread Starter
7th Gear
Joined: Mar 2017
Posts: 7
Likes: 0
electrical gremlin
Thank you for the response but 2 shops , lots of parts ...no one can diagnose this issue. It is related to the CC system . Causing voltage drop and fluctuation. Nothing anywhere on this issue. It acts like a relay maybe related to the fans turning off when CCM is switched to off ?? Or a switch or relay in the system that is driven by commands from the CCM. There are a few of those things. Low pressure switch has also been replaced. FSM useless on this. It only is an issue when the climate control system is switched off. The cooling fans will not come on until eng temp is at 225 plus. But it simply does not run right with the CC system shut off. Weirdest symptom I have ever seen in any car. It is not related to vibrations. Just to switching the CC system on and off.
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