Question about Cars & Trucks
Just bought this car, 1990 BMW 525i w/ 2.5 6 cyl, & auto, 159,xxx miles. Initial start up is OK, but when you give it some gas or put it in gear idel gets ruff, wants to stall. Has a ruff idel & stalls at stop lights. Hard to get it to start up again (cranks well, but takes awhile to start up again, ruff idle). Engine bogs down, runns porly. Have to keep RPM above 2000 to keep it running. First thought is idel control valve, any other sugestions for me? Check engine light is on, possibly due to large cracks in air filter box (letting to much air into engine?).
Can be a lot of things causing a rough idle. The first thing I would do would be to pull the code/s and see what it's saying. That will save you a lot of money. Other possible causes are vacuum leak, valve cover gasket leak, blown head gasket, MAF (mass air flow sensor), CCV (crank case ventilation), O2 sensor(pre-cat), IAC (idle air control valve), definitely the air box crack or filter, cam shaft position sensor, seals (VANOS), coils, fuel filter.
Again, I would get the code read and replace your air box before anything else. You don't want to be wasting money just guessing, remember also that even though the code may say something is wrong your going to want to take a multimeter and confirm that something is wrong. Test everything before you change.
Posted on Apr 25, 2017
Your fuel injectors maybe clogged up,have them cleaned.
Posted on Apr 25, 2017
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Posted on Jan 02, 2017
Common issue at the shop (i'm a ford technician), here is what I do to correct it.
Here is the most common cause of surges and stalls at stops and low erratic idle speed and rough idle, it is the idle speed control air-bypass valve and throttle valve (IAC for short), they get full of gunk over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.
Posted on Mar 11, 2009
NO U HAVE TO REMOVE THE IAC TO CLEAN.DO U KNOW WHET CODE THE LIGHT IS SETTING?
Posted on May 05, 2009
Sounds like a bad motor mount, pop the hood and see if the motor shakes or moves rapidly when u put it in gear holding down the brake.
Posted on May 10, 2009
Ignition system sounds probable on vhicle when everything gets warmed up. High pitched hum could be bad tire or worse bearing.
Posted on Oct 02, 2009
Testimonial: "Thank You for your response. The huming sound is present on idle from start-up,tires have just been replaced, would fuel pump be suspect?"
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