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.

 

[Kenny D]

Here is my Thread, I explain my catch can here. http://www.tahoeyukonforum.com/threads/kenny-ds-tahoe-to-go-thread.92097/

 

[bigfootchiro]

Here is my Thread, I explain my catch can here. http://www.tahoeyukonforum.com/threads/kenny-ds-tahoe-to-go-thread.92097/

That's awesome, and a great deal of help. Was the silicone adhesive to hold down the scotchbrite filter? I would think that if it were left loose that the vacuum would pull the pads close to the outlet to the plenum and plug it. I may be wrong though, just going off of physics haha. Also, how far up the can did you bring the height of the media to?

 

[Kenny D]

The silicone was to hold the hose into the fitting on the inside, I didn't want it to come loose and fall to the bottom. As for the scotch brite, it ended up being almost flush with the top of the opening. Also I ended up using larger pieces of scotch brite to close the gap around the edges. I haven't opened mine back up to see how much oil it has caught. I plan on checking into it when I change the oil. Although none is showing in the sight tube.

 

[Kenny D]

As for as a home depot oil separator, I don't know why you couldn't just use the filter it came with. Although thinking about it, you may want to reverse the flow on one of those, letting the heavy oil enter the bowl before being filtered. You would have to take a look at it without the bowl to be sure. With the amount of oil in your pictures, you either need a good size one or empty it out often. I just don't understand why you are sucking so much oil into your intake. Something is not right and a catch can is really just a band aid. I am surprised no one else has chimed in here.

 

[bigfootchiro]

As for as a home depot oil separator, I don't know why you couldn't just use the filter it came with. Although thinking about it, you may want to reverse the flow on one of those, letting the heavy oil enter the bowl before being filtered. You would have to take a look at it without the bowl to be sure. With the amount of oil in your pictures, you either need a good size one or empty it out often. I just don't understand why you are sucking so much oil into your intake. Something is not right and a catch can is really just a band aid. I am surprised no one else has chimed in here.

I definitely will get a larger filter. Tomorrow I will check out home depot and see what their selection is. If I decide I don't like it, I will probably do something like you did with yours. I am wondering why it's sucking so much oil too. Seems like their may be some sort of blockage in the head. I have a bottle of Amsoil Engine flush that I can use, but I hear the detergents may be too harsh for a higher mileage motor. May try ATF if that's less harmful. Let's see if anyone else chimes in on that subject. You have been a great help on steering me toward that catch can though and I greatly appreciate it!

 

[Kenny D]

No problem, I'm happy to offer my non professional opinion. If the heads were blocked enough to fill up the cavity to the point of sucking oil, wouldn't that starve the engine of oil at the pan? I'm leaning towards blow by on your rings. I am not sure if you want to go this route, but I had an older truck that had a weakening engine and I used a product called "Restore". It is supposed to help ring seal and eliminate blow by thus increasing compression. Just a last ditch effort IMO.

 

[bigfootchiro]

No problem, I'm happy to offer my non professional opinion. If the heads were blocked enough to fill up the cavity to the point of sucking oil, wouldn't that starve the engine of oil at the pan? I'm leaning towards blow by on your rings. I am not sure if you want to go this route, but I had an older truck that had a weakening engine and I used a product called "Restore". It is supposed to help ring seal and eliminate blow by thus increasing compression. Just a last ditch effort IMO.

You would think! I just don't know what else it could be, besides rings, you're right. Compression was checked on all cylinders and they were all very good still. I will get some Restore and try it out, wouldn't hurt! BTW, what do you think about this? You can add your own filter media into the baffle, but may need additional hose.

http://www.ebay.com/itm/JDM-BILLET-...ash=item5b33d2ad0a:g:7O0AAOSwfVpYrPC0&vxp=mtr

 

[Kenny D]

That would work, I'd use some 3/8 fuel line and pack the baffle area with some scotch brite or filter media. I am not sure if you would want it vented. I know the LS type motors have to be sealed, The 5.7 vortec probably would be the same so I would leave the plug where that filter goes on top.

 

[bigfootchiro]

That would work, I'd use some 3/8 fuel line and pack the baffle area with some scotch brite or filter media. I am not sure if you would want it vented. I know the LS type motors have to be sealed, The 5.7 vortec probably would be the same so I would leave the plug where that filter goes on top.

From what I read they have to be sealed. Looks like it comes with an allen bolt to plug it. Seems like a pretty simple setup! Now time to spend more money hahaha

 

[bigfootchiro]

@Kenny D as of right now the truck is running great! Only thing is cylinder 4 misfires at idle (gonna look into that, 51 PSI fuel pressure at idle), but not as bad as before. Other than that, 0 misfires across the board on all other cylinders!