Does a 98 vortec have a injector missfire code? (problem)

[Sprayaway Fox]

Workin on the 98 Silverado AGAIN. I have a cylinder 5 missfire that keeps coming up. I had cylinder #5 missfire with the old stuff, so I decided to put new Napa Cap and rotor on, Napa wires, and some regular autolite non platinum plugs in it

....and it keeps coming up. So I switch the plug and it still comes up, I switch the wire...and it still comes up. I pulled the plugwire off while running and it has spark to it. The engine didnt change RPM though that I could tell.

I know there was a problem with the Vortec injectors but does it have its own code or is it just cylinder missfire?

I keep getting a missfire. Nothing coming out of the exhaust that I can tell.

Any help would be MUCH appreciated.

[spooln30]

I think those motors have that "spider injector". If so that may be ur problem. It's one main injector and it feeds each cyc through a plastic line. They tend to crack and leak fuel So then that cyc may have a misfire. One way to tell is to open the throttle body and if it looks or smells real gassy it might be it. They are also known for the FPR which also over time leak but you would have more then one misfire. Hope this helps. One more thing check compression good starting point. Later

[rally_scort]

Did the misfire dissapear after the new cap/rotor? If it went away for a bit, check the cap again for corrosion.If its the stock-style disty, it could be your problem.We have had many come in with a missfire after a tune-up and slightly used cap/rotor.The problem is the venting in the body of the disty, causing moisture to get trapped.The new-style disty has venting that solves the problem.Its a long shot, but its stumped me the first few times before i caught on.

[Sprayaway Fox]

This is my 2nd new cap and rotor on here now. Truck doesnt backfire or nothing.

I know I have spark down at the plug. The compression checks in with all the rest. The Check light blinks sometimes but get off the gas and its full on. Oil pressure is good too.

[spooln30]

The flashing MIL light is from current cyc misfires. Did u look into the injector? I would def take a look at that.

[Sprayaway Fox]

Yeah I think I narrowed it down to the CFI now. Theres nothing left. Im gonna have a bud come over and bring his shop equipment over to flush the CFI. If it dont work...Looks like Im gonna have to do a MFI swap on the thing.

Thanks guys, Ill let ya know if the flush works out for me:thumbsup

[spooln30]

Yea the updated injector has a injector for each cyc. They look weird when u get it but just follow the instructions for how to run the plastic lines. And be careful not to kink the lines. GL with everything.

[Coops Brother]

Intake gasket vacuum leak???

[brotherbenn83]

Yea the updated injector has a injector for each cyc. They look weird when u get it but just follow the instructions for how to run the plastic lines. And be careful not to kink the lines. GL with everything.

The ORIGINAL injectors are replaceable individually. The newly designed injector come with all 8 in one assembly, and has proven QUITE reliable. Replacing them is quite simple, and cheap if you do just one. USUALLY when injectors fail, they are completely dead and you will have a constant miss. Did you check compression?

[Sprayaway Fox]

I did the ether around the intake and it didnt do nothing. Compression cold is 90 and 75 on cylinder number 5. This thing has 155K on it and its been ridden hard and put away wet....Just trying to get the SES light off for emissions. So I can use it for a work truck.

I did used 2 BG cans through the injectors tonight at 60 lbs. and cycled it through bringing down the PSI and back up a couple of times.

Since new plugs was hard to tell if it was firing. I know it cleaned up a bit but it was problably the other injectors getting cleaned. lol.

Oil pressure is great. No smoke.

Im gonna stew on it for a while and thinkin injector or burnt valve now. Ugggh This sucks.

[brotherbenn83]

75 is shitty compression. Pull the spark plug, and back off the rockers on that cylinder...then pressurize the cylinder and see where the air leaks to.

[Sprayaway Fox]

75 is shitty compression. Pull the spark plug, and back off the rockers on that cylinder...then pressurize the cylinder and see where the air leaks to.


Yeah it was shitty. I put a new injector in it and I have no SES light now and the compression came back in the cylinder after I let it cool down. Runs great!

The back of the intake was damp with fuel around number 5.

If anybody has to do this dont freak out, just take your time on the lines when you remove it from the cradle its in as they are not that bendable.

Thanks guys, nice to know that some of ya still tear into the newer stuff.:thumbsup