Help! Help, Please I am still getting gas in the oil in my 1989 C4

[Warr]

Well, I have put new injectors in, changed the oil, have new spark plugs, but still have backfiring through the intake, and I am still getting gas in the oil. Any ideas on possible causes?

 

[wolfuser]

what about the cold start injector?

Hi- did you change the cold start injector as well? if that´s leaking, you get unwanted fuel in the intake as well.

another reason for excess fuel could be not only leaking injectors but too high a discharge rate, i.e. the injection thinks it has to put in more fuel than the engine actually needs.

That should show in smoke in the exhaust and/or sooty spark plugs.

does your vette show any error codes? is the problem intermittend or continuous?

cheers
Wolfram

Well, I have put new injectors in, changed the oil, have new spark plugs, but still have backfiring through the intake, and I am still getting gas in the oil. Any ideas on possible causes?

 

[John Robinson]

This is for information purpose's only since it is from 93 manual. Take particular note to the second sentence. If you are getting fuel in the oil there is the possibility that the ecm is being told by the tps that it is in wot. If that is the case then the ecm is going to have the injectors pushing full fuel loads at the engine. If that is what is happening it seems to me that it is possible for you to get unburnt fuel passed the rings and into the oil. What this compares to is on the old carburetor engines if the float did not shut off properly the fuel would be pulled past the needle valve and the engine would be running rich.

 

[Warr]

Gas in oil

Hi- did you change the cold start injector as well? if that´s leaking, you get unwanted fuel in the intake as well.

another reason for excess fuel could be not only leaking injectors but too high a discharge rate, i.e. the injection thinks it has to put in more fuel than the engine actually needs.

That should show in smoke in the exhaust and/or sooty spark plugs.

does your vette show any error codes? is the problem intermittend or continuous?

cheers
Wolfram

Thanks, wolfuser. To the best of my knowledge, the 1989 doesn't have the cold start injector. Yesterday after my post, I discover a flow of gas coming through the vacuum line from the fuel pressure regulator, so it seems as if the diaphragm is leaking and filling the plenum, then the excess is running down around the rings into the crankcase(?). I have bought a new FPR and will put it in there as soon as time and weather permits. I sure wish that I had replaced this thing when I replaced the injectors! Now I have to tear it down again. As far as codes go, it is giving a 42, which I think has something to do with an ignition module problem. Earlier, too, I found a broken and degraded connector from the ICM to the coil, so I could have gotten some grounding. from that. Right now, I need to get it to where I can keep gas in it and can stop having to change the oil, and then clear the codes in the ECM to see what happens. The plugs that I took out were very black and sooty, and some were fouled, but I guess I know why now.. Thanks for your help and suggestions. I will post again with the results and maybe this might help any one else who has had the same problem. Thanks again!

 

[Warr]

Gas in oil

This is for information purpose's only since it is from 93 manual. Take particular note to the second sentence. If you are getting fuel in the oil there is the possibility that the ecm is being told by the tps that it is in wot. If that is the case then the ecm is going to have the injectors pushing full fuel loads at the engine. If that is what is happening it seems to me that it is possible for you to get unburnt fuel passed the rings and into the oil. What this compares to is on the old carburetor engines if the float did not shut off properly the fuel would be pulled past the needle valve and the engine would be running rich.

It was running very rich, but check out my latest post. Thanks John.

 

[Warr]

Gas in oil

Well, I have put new injectors in, changed the oil, have new spark plugs, but still have backfiring through the intake, and I am still getting gas in the oil. Any ideas on possible causes?

Problem solved! I replaced the fuel pressure regulator, cleared the computer, changed the oil and filter again, and so far everything is great and no service engine light. It starts quickly and the idle is smooth. The diaphragm in the FPR had started to separate and was letting gas flow into the upper intake and the excess was flowing into the cylinders and running down into the crankcase. I hope this helps others, and thanks again for all of your tips and suggestions.

 

[Schrade]

Check your static fuel pressure (leakdown time too) - injectors leak after 10 years (and 23 years)...

Where in NC? East? West?



ed.:
missed that you got new sprayers there...

 

[Warr]

Gas in oil

Check your static fuel pressure (leakdown time too) - injectors leak after 10 years (and 23 years)...

Where in NC? East? West?



ed.:
missed that you got new sprayers there...

Western NC. Where you at? Yeah,replaced the injectors first, with Bosch III's from FIC. Thought that I had a stuck one. It probably needed that anyway, though. My C4 is a work in progress.

 

[Schrade]

ALL c4's are WIP. If nothing more than cleaning and exploration (yeah - really) - learning where and what stuff is, and keeping them TUNED. But most would rather drive 'em, than keep 'em tuned...

I'm on the right side - nearer to the water. West side is good too - near Jessie there (gmjunkie - GM-knowledgebase ).