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View Full Version : 92 535i, check engine light at idle



scoobysmak
01-30-2006, 08:06 PM
Well it has been a while and I am going to give a little background to that might help solve the problem. Almost exactly a year ago I blew the head gasket in the car, I am sure it was from almost overheating it twice from blown radiator hoses and a faulty fan clutch (it was almost in the red zone on the temp gauge but not quite there). I pulled the head got it milled, and then put a new head gasket on and put it back together. After this I had a check engine light, I ran a computer on it and it pointed to the O2sensor. Since I had ran coolant through the exhaust I figured this was a good place to start, plus with 120k on the car couldn't hurt. Well I tried to replace it and after 15 hours of pain and grief I took it to a pro. He worked on it for about 3 hours before he just cut the old sensor off and welded a new O2 bong on. Well on the way home I noticed a big difference in performace but at idle I still had a check engine light. It comes on after around 15 to 20 seconds at idle 90% of the time, why it doesnt' do it all the time is a mystery to me. Normally it has a tendancy to be cold when it doesnt' come on at idle but has come on when cold. Other symtoms that maybe related is I have an oil leak somewhere, I smell oil cooking like I am pouring a bit on the exhaust manifold but I look and don't see any oil that looks new. I made a mess when I pulled the head off so I figured at first this was just old oil burning off at first but after getting the car hot a few times I figured this would be gone (I have driven the car about a 1000 miles after, its only 7.5 miles to work so it gets rotated between 3 other cars too, yeah I should be shot for not driving it more often). Another symtom is I have "squishy" brakes, the car stops fine but after setting for a second I can still press down on the brake pedal about an inch and a half. Well I am planning on using this car for a road trip and would rather use this car than any other, plus it needs a few road miles. I only mention the oil leak and the brake problem because if I have an oil leak that causes a vacum prolbem it may have affected both. I am not quite sure where to start but hope this information is helpful. Thanks in advance.

scoobysmak
01-31-2006, 09:15 PM
Thinking maybe it could be the brake booster causing the problem??? Any other ideas.

BimmerDude
02-01-2006, 01:35 AM
I had, what im assuming is the same problem with my 90' 535i the cause was improperly placed vacume hoses, another contributor was a leaking break booster vacume hose. I can post pics within 35 hours if you'd like.
the break booster hose joint was just leaking a bit of air.(it was cracked.)

632 Regal
02-01-2006, 02:40 AM
check all intake connections fot leakage, look carefully. as for the oil smell you will have to zero in on the leak. Inspestion should result in the problem.

good luck

632 Regal
02-01-2006, 02:41 AM
or low oil pressure.

winfred
02-01-2006, 09:18 AM
seen a couple 535s throw a light at idle (one was my car) bad idle control valve on one and bad 02 sensor was the other