cylinder with a wet plug using efi

[vector1]

hello all

have a cylinder with a plug that comes up wet and rich looking with black soot. other plugs all look normal and dry, affected cylinder (#2) leakdown is similiar to cylinders on either side. the cylinder is also getting spark, the condition has appeared on 2 different plugs in the same cylinder. the plug is not oily, just wet, as in gasoline wet. the cooling system is in good condition and don't believe it is leaking. doesn't appear to be a miss on the cylinder either.

i'm thinking the injector is leaking or running too rich or something. what would be the best way to check that the injector is firing correctly, i'm thinking of swapping it out for another and see if the condition follows or stays on the same cylinder.

[jhv48]

That would be the way to do it. Swap the injector with another cylinder and see if the problem moves with it.

My bet is replace the injector, problem solved. But only after you are darn sure the plug is firing at full strength. The swap will verify this. Don't forget to replace the wet plug after the swap and before you fire it up. It might be so wet that it won't fire no matter what you do.

Then check your oil to see if it smells like gas. If injector staying open, could be washing down the cylinder walls and diluting the oil. Time for an oil change!

[kitcarbp]

IF you have a check valve in the pump supply line that holds pressure after key-off, you can put a pressure gauge on the fuel rail and see how long it takes for the pressure to bleed down (within minutes or hours for leaking injector). If your fuel sysyem has a check-valve installed (usually part of the in-tank pump), your fuel rail should remain pressurized for several days. By seeing how fast the fuel rail pressure bleeds down will tell you if you have an injector(s) that are leaking. A leaking injector(s) symptom will also give excessive black smoke (rich) on start-up because of the fuel dribble from leaking injector into the intake runner(s), but once cleared of fuel runs great with no smoke. If you dont have a check valve in your fuel system, you'll have to confirm a leaking inj. by removing the injector and having it bench tested or swap in a know good one. This assumes you are confident the EFI harness for that injector is fault free (electrically its all sound). Make sure EFI ECU its triggering that injector correctly. I would also confirm you don't have an ignition issue on that plug wire or coil tower (or dist. cap terminal) to check the basics. You've ruled out the plug it seems, but ignition sys health upstream should be confirmed also.

[vector1]

interesting. interesting.. some things i hadn't thought about. i can check to see if it holds pressure easy enough with the gauge on the dash. the walbro fuel pump has a check valve. it does seem to start up a little rough so maybe the leaking injector is killing the cylinder. accel troubleshoots itself and no codes have come up......lately. don't remember a lot of smoke on fireup or during running.

[kobrabytes]

Are you stack injection?

Have you balanced the manifold?

[vector1]

Originally Posted by kobrabytes

Are you stack injection?

Have you balanced the manifold?

it's an accel gen7 dfi setup, uses a sup vic manifold. all plugs look good/similiar, just the one offender. i'm hoping a leaking or faulty injector and nothing electrical.