X5 stalled/set codes while being inspected!

[workingonit]

On another day. It took me another 2 hours to gather and put away tools (and at least 30 minutes to put the seat back in...cut the crap out of my hand doing so). At this point, I don't care what the dashboard fuel gauge says, I'll just fill it up and drive maybe 150 miles, then fill again. I'll get to it later this fall.

[andrewwynn]

The order of the seal is confusing because it almost always comes out with the assembly.

The level is averaged but if you don't reset it'll work itself out within a tank or two. How it affected me is that with a full tank it showed 3/4.


–awr–

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[workingonit]

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!).


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

[80stech]

Sounds like you might have HAD a weak fuel pump for a while and/or maybe a restricted fuel filter. Maybe reset adaptations and don't focus as much on the fuel trims.

[workingonit]

Originally Posted by 80stech

Sounds like you might have a weak fuel pump for a while and/or maybe a restricted fuel filter. Maybe reset adaptations and don't focus as much on the fuel trims.

I would think that it's the opposite; my old fuel pump was weak, causing a lean condition (it barely made 50 psi, four years ago, and didn't hold pressure in the line for long). Now, I'm getting increased fuel flow, causing a temporarily rich condition (possibly for awhile, as the fuel maps adjust?), as evidenced by increased acceleration, and negative fuel trims.

I've experienced wild swings in performance on a couple of vehicles before, after changing component(s): 1.) a CPU + high-powered fuel pump +injectors + race tune, and even on 2.) on a pickup truck, following a simple battery replacement (it had to re-learn everything, for some reason...my '04 Chevy 2500HD).

At least that's what I'm hoping it is, otherwise I'm going to have to use the parts cannon (fuel filter, regulator, lines, etc.).

[80stech]

Reset the adaptations to get a clean start from where the mixture should be and go from there. A new fuel filter would probably be a good idea anyway.

[andrewwynn]

The FPR will keep pressure constant. If you had too much psi it's the fault of the FPR which comes with the filter and if it's Original it's overdue


–awr–

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[80stech]

As far as the gauge, maybe check the connector and then take the pump out again and have a look, maybe something obvious with wiring or a bent sender contact. As I think I said before the picture of the Hella pump at RockAuto showed one of the contacts oxidized already so it would be a good idea to have a look at that and use some contact grease if you haven't already.

[workingonit]

I'll start with resetting the adaptations, then I'll dig out my fuel pressure tester and see what that shows. One of the last things my neighbor did before we swapped our vehicles, was to install a new Bosch FPR on the existing filter. He was cutting corners at that point in his refurbishment program, and when I aked why didn't he ask me for additional funds, or even help, he didn't have a good reason. Now, it's my problem.

If I can't get the gauge to read correctly, I will pull the pump and fiddle with the sender. I didn't grease any contacts (I was in a hurry), nor did I take time to test the sender with my multimeter. I hate doing an install twice, but I may have to, now.

If the fuel pressure looks good, the fuel trims settle down, and I grow accustomed to the sudden increase in acceleratory power, I can live with a bad sender (five of my last eight? project cars had bad fuel gauges, speedometers, or tachometers...or combinations of the three). I do my own workarounds.

[X5chemist]

LTFTs -4 and +4 = 0 Basically perfect! Short term will bounce around based on idle, running, and WOT conditions. If short term stay between -/+10, it's good. You might have a little carbon build up. Drive it like you stole it! Blow out carbon out the exhaust! Driving it like a BMW M4 eventually stopped it from smoking. I6 like RPMs! I better start planning on a fuel pump replacement soon. Maybe after it passes inspection this year.