My engine was just rebuilt. 90 3VZE. The #3(middle on passenger side) is fouling out with oil. At first I thought it was a bad plug. The I ohm'd out the plug wire at 15K. All other plugs look great. At about 4500 RPM under load it starts smoking. My thought process was that the oil was igniting at the higher RPMs causing the smoke. But I really don't know for sure.When I replace the plug it seems to fire fine for about 2 minutes then is fouled again. Not sure what else to check.

Where might the oil be coming from? Is it due to the ring not seating since it fouled?
Any suggestions or previous experience?

Thanks,
-PCP

 

Cracked or broken ring or not seated. Did they replace your valve seals? How many miles since rebuild?

 

75 miles on the engine. Valve seals were replaced. Rings could be it I suppose since it wasn't firing right so that cylinder never seated. Is there a way to get it to fire so they can seat?

 

Have you pulled the plug while connected to the wire & checked to see if you're getting full fire/spark on it under running conditions?

 

OK spent some time at lunch messing with it. I wont get into all the gory details ut tested the spark on 3 and compared to 1 and its the same. I have spare spark plugs to test with the new ones in the holes. Even though the plug had oil on it, it was still sparking fine. In my testing I tried going straight from the coil(I know dangerous) to see if I got a sputter out of 3 but nothing tried on 1 and 5 and both sputtered away.

Now I replaced all my injectors with remanufactured units(read cleaned) and didn't test them due to assumption(we all know what that means. I'm an a$$). I'm wondering since this hole isnt firing but has plenty of compression, shouldn't I be smelling gas when I pull the plug?

 

when you replaced injectors.. did you replace the o rings on the plastic grommet? maybe you're getting an air leak around the injector.

 

I replaced the grommet that goes into the plastic spacer that the spintle goes into, an oring on the top and a funky rubber spacer between the fuel rail and the injector. I will pull the plenum off when I get home from work tonight. Ohm out the injector and then test it out of the vehicle with a redneck test rig.

 

Pulled the plenum off and found that the injector was open circuit. So it wasn't oil fouling, just wasn't getting any fuel. Good thing I took the plenum off though as the leak I assumed was the oil cooler was in fact the inside drivers side valve cover. The gasket was pinched under the cover.

I will grab an injector from the boneyard today to make sure everything else is ok while I wait for the replacement injector from the rebuilder.

 

Replacement injector installed and all is well. Guess it was just a no fuel issue.
Thanks for all the help and suggestions.