jadiff

I've been chasing a problem with engine performance for a few weeks now. I'll be upfront about cleaning the engine just prior to having this problem, I also filled the tank just prior and wonder if (on auto-pilot)I used regular gas instead. I tried to be careful when I was cleaning the engine, but perhaps I doomed it anyway.

Some of the facts:
-1995 105K
-changed the fuel pump (following the manual because of low pressure), fuel filter and pressure regulator
-no codes until after the regulator was changed, now throwing an H42, not sure what to do about that.
-pressure seems to be low at around 38/40 when the pump is primed, holds steady and about the same after it is started.
-I do not see any pinches, etc. in the fuel line.

The engine seems to idle a bit rough with a few very slight mis-fires if I rev to 2500-3k rpms or so. If I try to drive it, acceleration is terrible and sometimes I have to put the clutch in to keep it from stalling. I have been afraid to get it above 20-30 MPH, so I don't know if it does any better at higher speed. I only take it through the neighborhood after I replace a part. The mis-fire/backfire is much more pronounced when I try to accelerate. It bucks an awful lot too.

I can change oil and brakes and do basic maintenance, so I am about out of ideas. My only other thoughts are to change the gas, the opti or perhaps an injector(s) is bad. Would the car behave this way if I got the opti wet while washing it? Any other idea or thoughts are appreciated.

floridamale

Never a good thing to get the opti wet, was it running OK before you washed it?

jadiff

Yes it was. I don't want to spend the time or money to replace it unless these are the symptoms of a bad opti. I'm not even sure if I could replace it myself.

floridamale

I think you have your answer then. See what some others have to say about it anyway. If you do it your self you will save quite abit over having a shop do it. You might think about replacing plug wire while you have it off it's the best time to do that also.
Good Luck

don hall

Instant moisture usually isn't an opti problem. It is the corrosion
that kills the opti. Note that I wrote: usually.

Replacement of the opti is more time consuming than technical.
If you feel that it is more than you wish to tackle, figure on about
$900 - 1200 for shop replacement.

Take a look at this thread, and determine if you want to do it yourself:

http://forums.corvetteforum.com/c4-t...-pictures.html

don hall

'Check Engine' light on? If so, we need the codes.

Checking for spark into, and out of, the opti is a simple check, so
you certainly want to perform a spark test.

jadiff

SES did come on after the pressure regulator was changed, H42. I did not have a light before.

jadiff

Wow, that thread was very helpful. Thanks a bunch for that. It looks like this is the next project. This isn't a DD so no rush, but I do miss driving her

don hall

From the Factory Manual:

DTC 42 will set when: The PCM detects 84 crankshaft revolutions without IC activity.

If DTC 42 is detected, the PCM will disable the fuel injectors to prevent flooding of the engine. DTC 42 will be stored in the PCM memory but will NOT turn on the malfunction indicator lamp.

Note: the 'H' denotes a history code.

Possible remedy: Test/replace Ignition Control Module.

Read thru this thread.... might help:

http://forums.corvetteforum.com/c4-t...ame-thing.html

Cliff Harris

You will get an error code 42 when the EST connector is opened to set the timing. ...and if the EST connector is not plugged back in after setting the timing.

Clear the codes and see if the error comes back.