daniel5625

on my 93 lt1, and still has a misfire!!!! ive done, fuel pump, injectors, new ICM, new wires, opti-spark, new o2 sensors. and still has misfire.

i replaced these parts to fix the misfire and its still there!

James93LT1

Any mods to the car, or is it still stock?

daniel5625

all stock

James93LT1

Spark plugs, what kind of injectors did you put in, when do you get the misfire.

daniel5625

the spark plugs looked good when i pulled a few, the injectors were bought from FIC, i had the misfire before the injectors also, i get it at idle, and it usually gets worse the hotter the car gets.

James93LT1

I would change out the plugs with a new set.
The injector are ok, I just asked to make sure you did not install a different size injector.

Strick

I know you're OBD1, but any codes? I, too, would replace the plugs and inspect each one of the old ones. Take a compression test of each cylinder.

tblt44

Do the plugs and open the hood at night with no lights around and look for firewoorks under hood at night

samsonb

It just takes one bad plug to cause a misfire.

daniel5625

i just did all the plugs, same problem.....

samsonb

Have you checked the timing and run fuel pressure checks? And I'm assuming you replaced the sock and pulsator along with the pump?

Looks like you'll have to go through alot of checks like EGR, vacuum leaks, leaking PCV, etc.

daniel5625

no i didnt replace the pulsator, it wasn't even the fuel pump because it had the same issue after i replaced it. how do you check the timing? i think part of the problem might be because i only have 2 bolts in the harmonic balancer because i stripped one hole.

samsonb

The problem could of been with the pulsator. Alot of guys just replace that with some high pressure fuel line. If I have to pull my pump out, I'll just replace that pulsator with some fuel line so I don't have to worry about that piece.

Did you replace the sock that is on the fuel pump?

And did you do any fuel pressure checks?

You check timing with a timing light.

I believe in another thread you mentioned about pulling the balancer and wasn't sure if you installed it correctly since you stripping one bolt?

You will need to get the balancer fixed first and make sure it is installed in the correct place before you check timing. I'm guessing the bolt that stripped is for one of the pulley bolts? If so, then just replace the balancer as it is a wear item anyways and go from there.

daniel5625

just pulled some codes, 41, 15, 72.

took the car out for a spin ran great was able to get it to rev past 4500rpm, but still has a slight miss, before all the new parts it would really lose power when you give it gas you couldn't go past 4000 rpm as the car got hot (about 220) , i don't know if it will still do that because i haven't really drove it much sense the new parts. i also put the sock on it.

i also was able the get the 3rd bolt in, helped a little but the miss is still there.

samsonb

These scans are from an 86. Probably would be a good idea to get a Corvette Service Manual for your year. You can get it on a CD off ebay for cheaper than getting it by book.

Code 41:

http://members.shaw.ca/corvette86/Code%2041.pdf

Code 15:

http://members.shaw.ca/corvette86/Code%2015.pdf

And it says a code 72 is Gear Selector Switch. Check connections at TCC solenoid and Park neutral switch. Replace ECM or repair transmission as needed.

I'm betting those codes have something to do with your miss.