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Old 04-17-2022, 07:50 PM
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Join Date: May 2021
Location: DFW Texas
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perhaps a clue that I can follow?

Originally Posted by andrewwynn View Post
With my foxwell scanner I can reset adaptations in the service main menu I think...Have you checked your fuel pressure under load? Pumps at end of life just get weak. The FPR hides their failure for an extended time, often after more than a year you just start getting lean codes that aren't MAF or vacuum leaks.

The car measures how much fuel by assuming 50.00 psi.

If its less, even if just under high throttle you'll get lean condition. Watch a graph of your O₂ precat and see if they go lean under heavy throttle that's a big clue.
In one of my posts I said I saw a "reset adaptations" somewhere in the service section, on my Foxwell 510, but was afraid to do it (it said reset ALL adaptations). Not knowing the full scope of adaptations involved, I didn't want to screw-up some other adaptation that was beneficial to the operation of the X5. I'll have to revisit the service section next week, after I return from my trip.

Once, I had trouble with my '04 2500 HD re-learning, after just fixing something or other (15 years ago, I can't remember what it was, but that it made the 120 mile round-trip commute very interesting the next morning/afternoon....)

Concerning fuel pressure, that could be why the P0313 code sometimes appears, along with P0171 & P0174. P0313 is when the PCM has detected a misfire in one or more of the engine's cylinders along with a low fuel reading in the fuel tank. I've been meaning to get this one, which I believe has been recommended on this forum
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As I stated above, I've been getting "lean codes that aren't MAF or vacuum leaks". Here's an O2 graph I made earlier;
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does it show what you're talking about here?
Originally Posted by andrewwynn
Watch a graph of your O₂ precat and see if they go lean under heavy throttle that's a big clue.
I have no maintenance records for this X5, and the guy I got it from didn't touch the fuel system at all, focusing on (in order) cooling system, suspension, axles, exhaust, "cracked" windshield, & timing chain/guides (plus other stuff). He didn't know what the previous owner had done, except for screwing up the radio (though he had kept the high-mileage truck moderately well serviced, with 4 of 6 door locks OK, all windows & lights working, A/C perfect condition, etc.).

This nagging problem is something that appeared 5 months into my ownership, but not prior. It may just be as you say, time for the FPR to get weak.
'01 BMW X5-E53 3.0i (born 7/13/01)
topas-blau, Leder-Montana grau,
my new favorite project car

Plus four GM vehicles: 2 Daily Drivers, and 2 modified trucks (for hauling & camping):
3 Chevys:
'09 HHR Panel LS 2.2L,
'08 Cobalt Coupe LS 2.2L,
'04 Silverado 2500HD WT Reg. Cab
+ a '98 GMC Sierra 1500 Ext. Cab

- and 20 others, now gone, that I've had over the last 58 years (not counting the stillborn "1965 ChevyII altered/gasser project")
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