Gas in the oil

Sisu01 · May 20, 2019

I buught a 2011 silverado 1500 5.3 with 130000 mi May . The oil became deluded with gas - I changed all 8 injectors with new Delco injectors. I'm still getting gas in the oil. It runs good - fuel milage is about 14 mpg. Can there be a problem with the computer keeping the injectors open after the ignition is off? Would a diagnostic check at a GM dealer show a problem with injectors?

PS the check engine light has not came on

Thanks for any help

Sisu01

sefiroxx · May 21, 2019

Use a scanner, check fuel trim to be sure they are cycling around 0 and not high positive.

Use a mechanics stethoscope to check if each injector is clicking.

If not, use a noid light to see if injector signal is getting to the injector.

riverbanks · May 21, 2019

The one question you asked, fuel after shut down?do you have a extended start?like, giving it some gas pedal to air it up?,or where is the black smoke out the tailpipe,what rpm?it should be noticable

dtnel78 · May 21, 2019

What's fuel trims? IF you have a bad O2 sensor it could be dumping fuel in the system but this sounds worse as if it's leaking fuel. 130k is to low for leaky rings, etc.

Have you did a clear flood crank? With the pedal pushed all the way to the floor and crank it and see if it has a steady crank sound.

IF you can create a video and upload the video to a free dropbox account and post a shared link here in the forums. We can listen to it then if you have someone to record while you perform the clear flood mode procedure.

IF it fires in clear flood mode then fuel is still getting thru.

Do you have a fuel pressure reading at idle and while driving? Running rough? Running it with fuel in the oil pan will cause premature engine wear due to the gas bring diluted and the stuff they use in it even though gas is made from .... Oil...

Let us know what you find.

The stethoscope method mentioned by the previous poster is a good first choice to try and inexpensive. I use that method a lot when checking for misses, etc...

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Sisu01 · May 21, 2019

It starts fine , runs fine ,never had a check engine light on. I have an appointment at the local Chevy dealer tomorrow for a diagnostic check. I did buy the truck used so it may be something the previous owner did (computer performance upgrades ?).

riverbanks · May 21, 2019

Yep, sometimes it's the best idea,but,one question,are you high on the dipstick or just a odor?

dtnel78 · May 21, 2019

3 hours ago, Sisu01 said:

It starts fine , runs fine ,never had a check engine light on. I have an appointment at the local Chevy dealer tomorrow for a diagnostic check. I did buy the truck used so it may be something the previous owner did (computer performance upgrades ?).

Was it a certified vehicle? Sometimes when you buy them from dealers they say they're "Certified". If so and it's a Chevy dealer if it turns out there's a tune on it or they say then ask them if they sold it to you if they checked for it as part of their "certification" process.

I wouldn't mention a tune to them as they should be able to diag that by looking at software revisions.

Sometimes looking for tsbs on issues like this can help as well.

Also the last post asked a good question, is the dipstick high or low? Also I'm sure you changed the oil initially after the injector issue? If it was a fair amount I'd probably change it a time or two to get the fuel out of the system.