Can we reset "adaptation, mixture"?

[kevinkay]

My test results:
fuel pressure with key turned jumps to 49psi then steadily decreases to zero (key still turned and pump running)
car on and running steady at 49psi, revving engine jumps very little, maybe 1-2psi.
car shut off - very quickly down to zero.
SO.......I am assuming I have a fuel regulator issue - or a leak in one of the lines that should hold pressure?? The filter is not that old, but I will start with that (regulator is built in??).
Even if pressure seems steady whit engine running could it still cause my "rich" issue in bank 2??

I did compression test and all 6 cylinders were between 200 - 205 psi. Can I rule out a valve or cylinder issue??
(I did not hold full throttle when I cranked -didnt read that until after....)

THANKS!
Kevin

[upallnight]

I think the check valve at the fuel pump is not holding pressure, or you have a leaky injector(s). Key on engine off, the fuel pump will run for a couple of seconds, but if the engine doesn't start the computer will not send power to the fuel pump to continue running, however, the check valve should maintain the pressure in the fuel rail. But since you stated that you have a rich condition you could also have an injector(s) that is/are not closing so the fuel pressure is being relieved at the bad injector(s).

A cheap fix will be to throw a can of Techron in the fuel tank and run a tank full of gas and recheck the fuel pressure and see how long it take to go to 0. Or you can bring it in and have the injectors cleaned.

When was the fuel pump replaced? The check valve is located in the fuel pump and not a separate component.

[80stech]

Also if there is a vacuum controlled regulator on the fuel filter it might have a leaking diaphragm. That might explain the loss in pressure and the rich condition since extra fuel would be going through the vacuum line.

[kevinkay]

THANKS for the feedback and not giving up on me!

The fuel pump was replaced very recently (5 months, 5,000 miles ago) as maintenance. before and after the pump replacement I had a "hard start" issue when engine was warm. I pulled the fuel rail and injectors - laid them on a towel, pressured the rail and watched to see if any leaked. Non leaked.

COULD it be......my "rich" Service Engine soon could be a failed regular on the fuel filter ??

Mann WK513 or Mahle KL167 is our OEM 16126754016?
(I have a Mahle Kl167 installed 5 moths 18,000 miles ago)

Thanks,
Kevin

[upallnight]

Originally Posted by kevinkay

THANKS for the feedback and not giving up on me!

The fuel pump was replaced very recently (5 months, 5,000 miles ago) as maintenance. before and after the pump replacement I had a "hard start" issue when engine was warm. I pulled the fuel rail and injectors - laid them on a towel, pressured the rail and watched to see if any leaked. Non leaked.

COULD it be......my "rich" Service Engine soon could be a failed regular on the fuel filter ??

Mann WK513 or Mahle KL167 is our OEM 16126754016?
(I have a Mahle Kl167 installed 5 moths 18,000 miles ago)

Thanks,
Kevin

Replaced with a BMW OE fuel pump or some cheap ass Chinese crap pump from eBay or Amazon? Even fairly new parts can go bad.

If you bought a BMW OE pump it has a 2 years unlimited miles warranty.

[kevinkay]

Replaced with OEM, perter-something. Bought only the pump and re-fitted into the old float setup.

New OEM fuel filter ordered and maybe delivered tomorrow.
Is there anyway I can check the vacuume line that controls the diaphragm on the filter when I have the belly plate open hiding the filter? - OR where that vacuume originates?

THANKS!

[upallnight]

Originally Posted by kevinkay

Replaced with OEM, perter-something. Bought only the pump and re-fitted into the old float setup.

New OEM fuel filter ordered and maybe delivered tomorrow.
Is there anyway I can check the vacuume line that controls the diaphragm on the filter when I have the belly plate open hiding the filter? - OR where that vacuume originates?

THANKS!

The vacuum line originates at the F connector on the intake boot that connects with the throttle body.

[kevinkay]

OH, I know that connector - in the accordion turn that usually rips...

So If pulled that line off I should feel suction on the hose side or connector side?

I know the large opening of that intake boot goes onto the throttle body, but where does the smaller turn off part get attached to? If my fuel filter diagram was spitting fuel or vapors through it - could it cause my "rich" error in bank 2??

THANKS!!

[kevinkay]

New fuel filter but still not holding pressure in the fuel rail.
Line from intake boot to fuel filter, no leaks.

not injectors
New elec. fuel pump
What else could cause fuel rail not holding pressure??

[80stech]

Don't let yourself get bamboozled with the oxygen sensor code, especially since we don't really know if your oxygen rich or lean. Bentley just says "pre catylist fuel trim bank 2" not what the problem actually is. If you have DIS maybe you could check what the fuel trim is actually doing like upallnight suggested. Remember the oxygen sensor can NOT sense fuel. "Rich in oxygen"(if that's even what the code is suggesting) can mean lean fuel or poor combustion from some other cause not even related to fuel. At this point I think that you might even have more than one problem as well. If your leaking fuel pressure there are only so many places that can happen and it may or may not be related to your fuel trim code.