E46Fanatics - View Single Post - Low Reference Voltage on Exhaust CPS Harness
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Old 09-18-2012, 07:40 PM   #18
OEM ///Member
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 23,210
My Ride: 330CiC, M5, X5, E93
Here is my theory, if you think your fuel pump/filter is giving you problems, for the $125-$160 you should probably replace the pump & filter.

Even if it does not resolve your issue, you have eliminated a typical failure point in the car and can then focus on other issues. The pumps soft fail and many people are surprise on the improved performance with a new fuel pump.

Also make sure your fuel pressure regulator vacuum lines are in good shape, both under the car and at the F connector on the upper intake elbow.

DISA, VANOS seals and MAF can also cause issue, however, the fuel pump is probably the cheapest and easiest thing to rule out. VANOS seals are not expensive, but add the valve cover gasket and the time to do the work, it is the most complex repair out of the 4.

DISA is an easy check and is about $175 for a replacement. MAF is close to $200 depending on which one.

The car is 9 years old, it is worth refreshing sensors as they do not last for ever, but a refresh is probably much cheaper than a new car and if you can DIY, most of these tasks are not too difficult.
Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616

Fuel pump failures - http://forum.e46fanatics.com/showthread.php?t=929501

Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491

Hidden OBC Menu - Check Voltage, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

E46/E39 GM5 Door Lock Info - www.bmwgm5.com

Lower hose temp switch O-ring - BMW #13621743299
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