Tune up
My 525it wagon is getting 15 mpg. Seems to be running rich by exhaust smell. Car has 168,000 miles on odometer. I am second owner and am guessing car has never had a prior tune up. My question is, Should I buy brand new oem coils. Will have to price check the coils. Advise needed. Dan
Big, Big Time Poster
I'd start with the plugs and see if that makes a difference before dropping the big bucks on coils. My son's e36 M3 was running lousy and improved dramatically with just plugs with the proper gap. You might check for vacuum leaks that would mess up your air/fuel readings.
1990 535im 421,000 miles, 1987 325is, 1989 325is, 1990 m3, 1991 318is, 2001 X5 3.0
Green Beret Special Ops
Yep, plugs first.
When you take the old ones out stick them in cardboard to keep them in order and then read them. Could be very helpful down the road.
95 E34 530I V2.37
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John F. Kennedy
Super Moderator
or visit the dealer and ask for a fault code readout, then you have the faults and then you repair the faulty parts instead of trial and error.
4 Grand Master
Use regular plugs... not those +4 junks... single one is best.
It is most likely you have to change some sensors... and seals... as you most likely have vacuum leaks.
Mass Air Flow sensor should be cleaned with MAF cleaner.
Will change plugs since I did put four prong plugs in. Also will get mass air flow sensor cleaner. Where is the fuel filter? Dan
4 Grand Master
fuel filter in rear right wheelwell... fuel filter rarely ever cause bad fuel mileage... 99$ chance it is not the problem.
Fuel pump however does affect fuel mileage and power.
Major Contributor
You mean the dual ground electrodes, Bosch FR7LDCR (BMW OE)? I believe superseded by plus (FR7LDCR+).Originally Posted by Tiger
RICK
BMW 1995 525i (Alpine White)
Major Contributor
This seems like a very low number for m50 engine. Please check compression, leak down.
Please check vacuum at the brake booster. Foolproof procedure - remove the vacuum pipe from the manifold and try to suck in. The brake booster should not allow air into the engine.
A Bentley's repair manual should provide numbers for checking the coils, along with much other needed maintenance information, which would save money in diagnostics and repairs. Please consider investing in it first.
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