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Hi, I've got a 1990 corvette c4 and last week it decided to start misfire and backfire. I've been reading alot of threads on here that talk about an optispark problem but looking on parts websites I cant see an optispark for a 1990 vet, did they start adding these to the cars after the year of mine? either way any advice is appreaciated, replacing all the spark plugs tomorrow to see if that helps.
I ordered a fuel pressure gauge today to check that.
Doesnt idle very well
Misfires
Backfires
struggles to start at times and starts well at other times
and Cut out once
Main thing is if 1990 has an optispark or just a coil?????
Btw im in england so parts are a bit difficult to come by.
Your 90 does not have an opti-spark. Until you check the fuel pressure first than go from there. Does your 90 still have cats? I ask because you can have similar issues from stopped up cats. How long has it been from a complete tune up? Plugs, cap, rotor, wires, fuel filter?
To be honest I've owned it for about a year and a half and havent needed to touch it other than replacing the bearings in the headlight motors. The guy I bought it from serviced it but im not sure what he did. I've ordered a new fuel filter but checked the one thats on there and looking in it as much as I can it looks pretty clean.
Today I checked the condition of the fuel pump and the mesh that is attached to the bottom of it has a tear in it so i'll probably need a new one. Checked for tapping of fuel injectors with a screw driver and they all seem to be working fine, havent pulled them out though. Thats as far as I've got at the moment.
Spark plugs will be changed tomorrow and waiting for delivery of fuel filter and fuel pressure gauge
Your 90 does not have an opti-spark. Until you check the fuel pressure first than go from there. Does your 90 still have cats? I ask because you can have similar issues from stopped up cats. How long has it been from a complete tune up? Plugs, cap, rotor, wires, fuel filter?
oh sorry, it has a straight through 4 exhaust system from what I can tell. im not a mechanic but can handle a "take one off put one on system"
Was the small rubber line going from the pump to the line in good shape, sometimes when they get old they swell or the clamps come off and you lose fuel pressure.
Was the small rubber line going from the pump to the line in good shape, sometimes when they get old they swell or the clamps come off and you lose fuel pressure.
If you mean the rubber tubing on top where there are 3 tubes, then 2 were good and one looked like someone couldve tried to slide it off with a screw driver and split the end but the jubilee clip or pressure clip was set lower down to where the gash was
10-09-2015, 02:09 PM
1990 corvette misfiring, wont rev past 3k rpm
