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Some suggestions for your problem. (archive)
[ Follow Ups ] [ 7-series (E23) Message Board ] [ Msg. Board FAQ ]
Posted by demet 85'745 CT on March 11, 2002 at 12:34:58:

In Reply to: FOR DEMET OR JENS (LONG) posted by john 87 745/ 87 L6 on March 10, 2002 at 06:39:18:

First off, if you think you have a fuel delivery problem then you need to follow the diagnostic steps that will lead you to that conclusion. With the help of a stethoscope or a piece of hose, you can hear the in-tank pump from the trunk. Obviously just hearing both pumps running isn't enough. That's why a proper test of fuel delivery calls for both pressure and flow tests. Personally, I wouldn't replace a $200 component until I was sure that it was flaky.

A low idle could be caused by a number of things. One of the simplest is that the idle control valve hasn't been adjusted for proper idle speed. With the engine warm all you need to do is open the valve up until the you get about 800 rpm. Assuming of course that there are no vacuum leaks. Then you need to check the cold start fast idle is set properly. Cold start fast idle is controlled only in part by the idle control valve and is augmented by the aux. air bypass valve. If you find that cold start fast idle is set too high then the aux. valve may need to be adjusted or replaced. Adjusting it is a bit tricky as it has been locked into a preset position. Cold start fast idle shouldn't be more than 1,100 rpm and should last a max of about 8 minutes. That's how long it takes for the aux. valve to gradually close off when cold and for normal warm idle to return. While you're there looking at things it's a good idea to pull the rubber hose that connects both the idle valve and aux. valve to the intake manifold and check it for cracks.

Regards
demet


HELLO GENTLEMEN: I NEED YOUR HELP IN SOLVING A FEW PROBELMS: 1. AFTER WARMING UP CAR I AM GETTING A VERY LOW IDLE ABOUT 400-500 RPMS BUT THIS ONLY HAPPENS WHEN THE CAR IS A NORMAL RUNNING TEMP. AND IN GEAR. 2. I HAD THE VAPOR LOCK PROBLEM AND BOUGHT THE CHECK VALVE FROM BMW ($3.00). MY BMW CERTIFIED MECHANIC INSTALLED TO LINE LEADING BACK TO THE TANK IS THIS CORRECT???(THE LIE THAT RUNS FROM THE FUEL PRESSURE REGULATOR) 3. ALSO FROM READING OTHER POST IT SEEMS TO ME THAT I WILL BE NEEDING AN INTERIOR AND EXTERIOR FUEL PUMPS. DO U RECOMMEND THE VEGA FIX FOR THE IN-TANK PUMP AND WHAT WOULD USE FOR OUTSIDE FUEL PUMP? ANY HELP TO THESE QUESTIONS WILL BE HELPFUL?????? PLEASE ANYONE ELSE READING THIS IF U HAVE ANY IDEAS PLEASE FEEL FREE TO SEND THEM. THANK U.




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