Rough Idle, Multiple Misfires, Oily Injectors? Pics attached

[bigfootchiro]

Today I decided to start over from square 1 with my misfire and pull the MPFI unit out and put a new one in, thinking that I may have screwed up the install somehow. When I pulled it out, the injector housings were very oily, and Cylinder #4 was especially brown which you can see in the pics (picture #3; this is also the cylinder that misfires the most). The Data Logging pic shows the Misfire History; however, I have seen Cylinders 6 and 7 misfire under Current Misfires, but they must not be enough to register the history. My question is would the oily injectors be the cause of the misfires, and if so, where is all this oil coming from? Bad EGR? Keep in mind, this MPFI unit has under 1000 miles on it, and I have not put the new one in yet.

Thank you in advanced!

 

[bigfootchiro]

I'll throw this out there, maybe it will flip a switch: worse misfires are coming from front half of motor, with the exception of cylinder #8. Also threw a P0141 code O2 Sensor Bank 1 Sensor 2 code the other day, but has never come back on since.

 

[Kenny D]

PCV valve bad? Don't see how oil is getting in there other than through the PCV system. Are your spark plugs oily?
Engine smoke?

 

[bigfootchiro]

PCV valve bad? Don't see how oil is getting in there other than through the PCV system. Are your spark plugs oily?
Engine smoke?

I will pull them again, but I do believe the #4 was especially oily. That spark plug was changed out for a regular AC Delco, and when pulled the other day did not look anywhere near what this picture shows of the old one. I have not noticed any smoke coming out of the exhaust. I used to have an oil leak that I traced back to the passenger side valve cover, but after running a bottle of Lucas through, it no longer leaks. The PCV valve, grommet, and hose were replaced when I did the MPFI, doesn't mean it's not blowing oil up through, though. I have noticed a decent amount of oil coming up through the vent tube on the passenger side valve cover that connect into the air intake, however. If it were the PCV system, would there be a blockage in the heads?

 

[Kenny D]

Unless the PCV valve is stuck shut and not letting the intake pull a vacuum, it could be from blow by. Also on the inside of your valve cover where the PCV valve is, there is a baffle. Maybe it is clogged. Try pouring a little oil through the grommet and see how fast it drains. Do you have a catch can installed by chance?

 

[Kenny D]

BTW, if your EGR was bad, you'd get a code on that one too. I dealt with a EGR code for the last 2 years of my 99 burb ownership. Even a new EGR wouldn't make it go away.

 

[bigfootchiro]

I do not have a catch can installed. Can I buy one or do I have to make one? Does it go under the valve that the pcv connects to on the plenum? I blew air through both that connection and the pcv and there are no restrictions.

 

[bigfootchiro]

However, these two are coated with oil! So it's sucking too much oil through the PCV into the plenum? Next thing is, what causes that?

 

[Kenny D]

Wow, I do not know what would cause all that but you would really benefit from a catch can setup. You can buy them from Ebay although the cheap ones on there will not have a baffle system, or https://catchcans.com/. Install in line between your PCV valve and the intake. The can will catch all that oil getting by your PCV valve. Some people have used the inline oil separators from home depot. Search the forum for catch cans and check this thread for ideas. http://www.tahoeyukonforum.com/threads/get-a-catch-can-before-any-mods.49716/

 

[bigfootchiro]

Wow, I do not know what would cause all that but you would really benefit from a catch can setup. You can buy them from Ebay although the cheap ones on there will not have a baffle system, or https://catchcans.com/. Install in line between your PCV valve and the intake. The can will catch all that oil getting by your PCV valve. Some people have used the inline oil separators from home depot. Search the forum for catch cans and check this thread for ideas. http://www.tahoeyukonforum.com/threads/get-a-catch-can-before-any-mods.49716/

Wow, looks like a solution! Thank you! I read through all 51 pages this morning haha. I saw that you started posting toward the end. Instead of ordering one, I would like to get it ASAP before I run the truck with the new MPFI. When reading I noticed people stating using a stainless steel filter mesh. Where does this filter mesh go in the actual filter? Seems like some fine mesh steel wool will work.