750IL oil consumption problems

[flclkrazy]

I have a 1991 750IL with 160k miles that is giving me trouble and would like help narrowing down the possible solutions.

Problems:
-Eating a quart of oil every 100ish miles
-Runs rough and blows smoke with a hint of blue
-Bank 1 gets noticeably hotter than the other side
-Bank 1 has low steady vacuum reading of 9 in Hg at the intake manifold that increases to 11 in Hg as it warms up
-Engine overheats while in gear and vehicle is stopped, neutral or park and it cools back down
-All spark plugs on bank 1 have a layer of burnt oil on them after running less than 300 miles
-Stomp code 1222 Lambda Control System Bank 1: The ECM has been unable to maintain Lambda (fuel mixture or fuel trim) on Bank 1

Stuff I've changed over the past year:
-New PCV/VCV and hoses
-Resealed intake manifold gaskets
-New intake boots
-New valve cover seals
-Safety-wired the oil spray bar bolts
-Cleaned the throttle bodies
-New sparkplugs
-Rebuilt the fuel injectors

My thoughts are that the low bank 1 manifold vacuum is caused by the computer opening the throttle valve at idle to try and correct for out of whack lambda values. The lambda values are messed up because of the high amount oil being ingested. All sparkplugs in bank 1 are oil covered, so I assume the oil is coming from leaky valve stem seals? I even removed the VCV system temporarily and let it idle for a half hour, still was pouring out smoke. I'm looking for any other ways to explain the problems before I go ripping off the intake again...

[SergeBMW]

If you let the car sit for a few days, does it blow blue smoke when you first turn it on? If not you may have an issue with stuck or bad piston rings. If you do see burning oil on first start after a few days, then your valve seals will be leaking down into the cylinder. Did you have this issue before? And have you had vacuum leaks before this work? Have you also replaced the intake gasket for the throttle body and the cap in the rear of the intake mani? Check for any vacuum leaks with carb cleaner or flammable brake cleaner. Im sure you did a good job, but we always make a mistake, I would go over and make sure there are no vacuum leaks.

The fact that you have oil on all the plugs from one bank indicates to me more of a PCV issue than anything else. It could be the above but that engine would have had to take a beating at some point in its life.

Something to try... I have never been a fan of additives, but I have seen the Engine RESTORE stuff work wonders in BMWs before, especially with compression issues. I have just purchased one last night and put 2 6 cylinder cans in. Only drove it home (5min) as it was really late, but ill let you know how well it went.

Also I read that your car overheats? You need to address this first. Check the Visco fan clutch is working properly as well as make sure all the air is out of the system and bled properly. Not sure if your 1991 comes with the auto bleed system, my 89 does not.

[shogun]

One more hint with regards to the low vacuum on one side, I have seen one valve cover where the passage for the vacuum was clogged, the valve cover is a kind of double walled piece, remove no. 2 and the see if there is the same vacuum on both valve covers
http://www.ow.no/index.php?option=co...&g2_itemId=183
or blow compressed air thru the opening

[tsmcg161]

Did you do a compression test? What are the Mercury readings on bank 2?