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Old 10-27-2025, 06:32 PM
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Update, after first test drive with new fuel pump

Following the installation of the new Hella fuel pump on the 21st in this thread https://xoutpost.com/bmw-sav-forums/...inspected.html, I only drove it down my driveway just far enough to turn it around, and left it at that. I rested a few days (of course I did, after every repair job I do, now) and finally, after some rainy days, decided to make a test drive today, on the 27th.

I had two items on the agenda: fill the tank, so I would know where the level was (I don't trust the gauge, since it reads full, and the tank wasn't), and to get the emission monitors to "complete" by driving a "drive cycle". The fill-up was 9.6 gallons, so I know that the gauge is wrong, and my "drive cycle" completed all but three monitors (I only drove 10 miles, in a loop around my semi-rural house, due to backed-up rush-hour traffic).

I'll drive another cycle until all, or all but one, monitors are complete, before I try again to get it inspected (its' final emissions certification, hooray!).
Name:  resetting emission monitors, after fuel pump install.jpg
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Problems? the X5 almost stalled twice (once backing out of my driveway, second time leaving the gas station onto a secondary highway)...it never previously did that. Plus, now, the accelerator is extremely responsive, with no hesitation (which it had before), so much so, that I thought it was in Sport Mode (making downshifts) or someone installed Nitrous on the M54, it was so much. And, there was another difference....

I've been chasing lean fuel trims for 4 years now, unsuccessfully, but they've been brought mostly under control sfter X5chemist donated a "proven to work" Siemens MAF to me (thanks again!). I monitor them constantly on my dashboard-mounted Android tablet running Torque Pro. The STFTs bounce from about +4 to -10, to adjust the LTFTs that stay in a +3 to +8 range (plusses indicating a lean condition). To my astonishment, I'm getting rich condition numbers, now.

While the LTFTs have started to waffle between -4 and +4, the STFTs are all over the place, and have gone as far as -28.5 at times, under acceleration. WTF

Even at idle, inthe driveway upon returning home, it still looks odd (rich) to me
Name:  after fuel pump install.jpg
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01 BMW X5 E53,3.0i-5L40E, 7/13/01
topas-blau,Leder-grau,"resto-project car"

Here:
14 Lexus ES350,3.5L-U660E
09 HHR Panel,2.2L-4T45E
04 Chevy 2500HD,6.0L-4L80E
98 GMC Sierra 1500,5.7L-4L60E

Gone:
66 Chevelle Malibu 2dr ht.,327>441c.i.-TH350>PGlide/transbrake
08 Cobalt Coupe,2.2L-4T45E
69 & 75 C10s,350c.i.-TH350
86 S10,2.8L-700R4
73 Volvo 142,2.0L-MT4
72 & 73 VW SuperBeetles,1.6l-MT4
64 VW,1.2l-MT4
67 Dodge Monaco 500 2dr ht.,383c.i.-A727
56 Chevy 210 4dr,265c.i.-PGlide

Last edited by workingonit; 11-02-2025 at 11:06 AM.
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