93' LT1 little over 100,000 , bone stock. Started out flushing the radiator and it got everywhere, initally shorting out the opti-spark. So dad decided to put a used, water pump and opti spark on it.....bad move, it leaked and shorted out the second opti spark. So we got brand new opti spark, and water pump. Some time before someone had done plugs and wires on it, wrong plugs, MISMATCHED plugs, and 2 of them on the passanger side I took out with my fingers. So I got the corrrect plugs, gapped them right, and put new wires and back in there holders. When I fired it up, it loped at an idle like it had a cam, and sputtered under acceleration, almost like a crossed wire. Checked the wires 5 times, they were right. It was only missing out of the passanger tail pipe. Dad drove it anyway, and for too long, now theres black soot on the bumper on the passanger side, and now it missing and black soot on the drivers side also. It got so bad now it will barely move under its own power, and we checked the plugs and they are just about fouled out. Did a fuel pressure test and it was within spec, low 30's I believe...dont know, its been a while, and I dont believe it leaked off very much either. I dont really know where to start guys, it's been sittin for 2 years tho, and thats long enough. I could'nt pay someone to come over and look at it and I dont know why. Any suggestions would be great. Someone mentioned the FPR but why would it have started out just mising out of the passanger side and not both? The fumes were so rich it would burn your eyes. Oh yea....it quit runing all together a while back so I replaced the coil and the ignition module and it ran again, but with the same problems.

Thanks in advance!!

 

I think low 30's is too low for fuel pressure. If i'm not mistaken, the required FP only went up during the years, mine is an a 85 and requires about 40 psi.

 

But if it was too low, it wouldnt be loading up tho would it? I remember checking the book and it was within spec.

 

First remove the vacuum hose from the FPR and check for signs of fuel in the hose and/or FPR nipple...if you see signs... the FPR diaphram is likely ruptured...if that checks good... ohm check the injectors w/VOM each one should be around 16 ohms....may have a injector partially stuck open...does the fuel pressure hold after running and you turn off the key or drop very quickly ?

 

When u first turn on the key it instantly goes to 46 psi, then a split second after that it drops to 43, and gradually leaks down to around 36-38. Sometimes faster than others, sometimes it will stay at 40 after all that, and leak no further.

 

through all of this has the "ck engine" light come on and have you checked for codes ?

 

The very first thing you should do whenever you have driveability issues is Check for error codes. It could be as simple as a bad O2 sensor on the passenger side exhaust causing the right bank to run rich.

Your '93 will have the 12 pin type ALDL connector, and you can retrieve the codes yourself using the paper-clip method.

http://www.corvettebuyers.com/c4vettes/codes.htm

 

i checked the codes and the only thing it came up with was the egr valve, but it only set the light off at higway speeds, then went off. While it's acting real stupid no codes have popped up

 

I read that page, and when i scanned it, i counted the flashes of the service engine light, nothing ever came across the speedo.

 

Hi,it sounds like your car is mis-firing.Check to make sure you installed the optispark correct.And double check your plug wires and your spark plug gap.If its not throwing any codes its mechanical.

 

For some strange reason I am thinking bad injectors. But first a simple test - run it at night and look for sparks from any shorted plug wires. Then drip a drop of water on each exhaust manifold port and any water that doesn't sizzle means a dead cylinder.

 

another issue could be that your car was sitting for 2 years and the gas is bad. Did you put any kind of stablizer in it 2 years ago ??

 

I checked those things several times over, even changed the plugs....again. It was acting stupid before we started changing parts , its just got way worse.

 

I did the spark test at night.....nothing. If I can get it running long enough, i will do the water test. I think we even pulled off one wire at a time, and it seemed to make no difference at an idle

 

no....since its been running so bad its been sitting 2 years, it was a daily driver when this happened.

 

Did you at least see a sequence of C12 on the speedo?
flash (pause), flash, flash, (long pause)


This is not an error code, but tells you when you are at the start or end of an error code serial dump.

 

This sounds like a good place to start also. If it did run rich for so long a period of time, that in itself will kill an O2 sensor.

I think my fuel pressure runs about 34-35 or so and would think you are probably OK on this and not to cause the sever problems you have.

 

Well guys I ohmed all my injectors, and they ranged from 12.3-12.5. I could not get it started it would hit a few times and gas smoke billowed from the exhaust. I did pull the vac line off the FPR and it looked a little damp down in the FPR, but i couldnt get it running long enough to really see if fuel was sprawing out. I did suck on the hose hooked to it and got a distinct fuel fume taste in my mouth, but no fluid, this is also the first time its tried to be started in over 6 months.

 

I cannot remember, i might need to try it again huh?

 

thoughts?