reset fuel trims; lasted about 60 miles or about an hour

[Effduration]

I don't believe the schrader valve on a BMW fuel rail is the same size as a tire schrader valve. But that is not, at this point, a concrete fact... Not sure what the slime kit has to do with anything.

I already got off my arse once and dug out my fuel pressure kit and listed the part number...When I get a moment, I'll go back and see if it lists the thread size..

[andrewwynn]

I know I've used tire valve caps on my fuel rail but it was plastic so the threads could be slightly off and still mesh ok.

[workingonit]

Originally Posted by andrewwynn

It looks like the black seal is incompatible with fitting this on. Pull that out and see if it threads on. Bonus it will release the fuel pressure if the bar works to press the Schrader button. (Have shop towel handy not a lot comes out if the engine is stopped).

If that works, Teflon to seal at the threads vs. the edge of the valve.

Actually, that fitting is #11, not #4. I didn't pay attention when I glanced at the list. I just chose that one as an example of a valve depressor. That adapter is 7/16"-20 UNF on both ends. No other fitting in the kit has a depressor bar (except the main hose on the gauge, also too large for the Schrader). #11 also fits to the hose attached to the gauge, not to the Schrader, but it is a right-angle adapter.

andrewwynn, can YOU tell me what adapter size/thread works for you?

[andrewwynn]

I might be able to stop at the garage and check the fitting.

[workingonit]

Originally Posted by Effduration

I don't believe the schrader valve on a BMW fuel rail is the same size as a tire schrader valve. But that is not, at this point, a concrete fact... Not sure what the slime kit has to do with anything....

I was using what tools I had on hand to contrast & compare the fuel pressure gauge fittings (that came in my gauge kit) to a spare T-16 Schrader valve on my desk (bought for making my smoke test machine). I used the slime kit to try to match-up threads and also see if the special valve core tool might clean-up, or possibly recut threads. I'm not about to simply try and force the fittings to fit onto the fuel rail Schrader without some basis for comparison.

I've read so much conflicting info on the Schrader valve sizes used on various tires, fuel rail ports, and their associated thread sizes (plus such descriptions as "large" & "small" that are absolutely useless without thread sizing), that any first-hand knowledge gleaned may be of use to me, in lieu of getting absolute confirmation of a fitting's thread size from someone that actually used one on an X5 3.0i fuel rail Schrader (preferably on an E53).
my fuel rail part number

I've read hundreds of posts about problems connecting to the Schrader, others about weak welds/solder joints on the rail itself (with pinhole leaks or larger, causing me some concern about forcing a connection there), and dozens of parts lists for tester fittings that are claimed to work (but nowhere the actual thread size). And then there is newtis info on special tools (of unobtainium) that are touted as the ones to use when testing fuel pressure.
not available, and with no actual sizes given

I'm trying to figure out a workaround, to check pressure at another location. Maybe prior to the rail, in the preceding fuel hose, or underneath, exiting the filter/regulator. I'm perusing the fuel system schematic, prior to actually exposing the actual parts involved (hands-on), since I have no prior experience on high pressure fuel injection systems (always had GM systems that were easy to work on), or on any European car (except for replacing a 4" hose on my '73 Volvo, 45 years back).


I'm also thinking about getting a spare fuel rail, just in case of breakage, and if there's no problem , then modifying the spare rail to have a permanently-mounted pressure gauge underhood (not on the windshield wiper cowl, like on my drag race car), with a standard-sized Schrader attached. Going off on a tangent, again.

[ahlem]

I'd suggest taking a trip to your local Parker store and see if there is a BPP fitting that has the correct thread size. I did that once but can't remember which of the pretty many BMW models I did that for.

[andrewwynn]

A steel valve cap for a tire will confirm if it's the same. Also it should have had one and check if that fits on a tire valve stem.

[X5chemist]

Originally Posted by workingonit

P.S. to X5chemist and Effduration: does your kit/fitting/gauge actually state the size and threading of the adapter? that fits and works perfectly? “Inquiring minds want to know” as they say.

I’ll check kit for sizes. Better yet, I’ll ask my cuz for info. Maybe BMW can tell more about the test port.

[workingonit]

Originally Posted by andrewwynn

A steel valve cap for a tire will confirm if it's the same. Also it should have had one and check if that fits on a tire valve stem.

The steel cap on the fuel rail fit on the tire valve and screwed halfway down, then felt like it was about to crossthread; it screws all the way down on the fuel rail Schrader, though, smoothly. That's why I wondered about the fit of the M8x1 fitting, since it felt similar on the fuel rail Schrader, prompting me to try the tire valve clean-up tool on the M8x1 fitting. It doesn't do a thing, telling me that it's obviously not the same thread.

I don't know if the brass fitting is M8x1 NPT? (or the Euro/Asian equivalent, or what). If I summon up the guts to risk breaking the Schrader off the rail (I'm infamous for my heavy-handed tweaking of aluminum parts), using the #8 fitting over the exterior of the fuel rail Schrader, then I'll use about two turns of the thick-er Teflon tape to try to seal the fitting, which will only turn a few threads down. It's probably my best course, as opposed to an alternate workaround.

In related news today, on another trip to another Dr's lab (my newest hobby), the Torque Pro app on the dash said that my long-term fuel trims had now risen to 11.72% each (after being at zero, after resetting the MAF and clearing adaptations awhile back). The short-term fuel trims were bouncing between a high of 10.67% to a low of -11.72% (as observed, with the highs under rapid acceleration, and the lows just following that, on deceleration). And the MAF was sitting at 5.6 g/s (at 700 rpm, in gear, with A/C running, at stoplights). I'm feeling that the MAF sensor is not a problem, afterall.

No driveabilty problem (ever), nor faults were recorded on my 22 mile trip (now the X5 has 210685 miles, which means I've driven it only 676 miles in 11.5 months...<1.93 miles per day). I used to average over 100 miles a day, when commuting to work and weekend racing.

[andrewwynn]

I found this;

External 8V1 thread: 0.305 in (7.747 mm) x 32 TPI[4] (1⁄32 in or 0.7938 mm pitch; tap size 8v1-32)

No idea what the hell 8v1 is.