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

[X5chemist]

Scooby-Doo asks which listed fitting fits?

[workingonit]

Originally Posted by X5chemist

Scooby-Doo asks which listed fitting fits?

Scooby-Doo ??? You're telling me your age; I was already 19 when that premiered on TV in 1969, and of course, I never watched it.

As for which fitting works, actually, none do. Fitting #8 (m8x1)
#8 on the previously posted list
screws halfway down on the fuel rail Schrader, but doesn't give me any confidence on the thread match. I'll have to use a second fitting to attach it to the gauge's hose.
necessary connection to join to the gauge
The premium Teflon tape would probably seal it, but there's another problem...the fitting doesn't have a "valve depressor" inside.
this one isn't even close to working

If I remove the valve core from the Schrader, and join two fittings (plus Teflon tape), I can probably test the pressure. I should probably wear a raincoat, and have my wife stand-by with a fire extinguisher, because I can envision fuel going everywhere.

Why can't I find any mention on the internet of the thread size used on the early E53 (M54) fuel rail? it's like a BMW state secret or something. What did other people use? I can't imagine that the Harbor Freight, and other cheap testing kits have a "BMW-approved" fitting, while my kit doesn't (they're all probably made in the same factory in China).

Meanwhile, in related news: I went ahead (while I had the covers off) and sprayed 3 more cans of carb cleaner, and found zero leaks, again, paying particular attention to the rubber boots, vacuum junctions, injector O-rings, vacuum manifold O-rings, and any BMW plastic connectors. I also waited until everything was warmed up before I observed the MAF readings from idle (700 rpm) to 1k, 1.5k, 2k, and 2.5k. They were consistent with or better than on my previous graph, so I didn't save it.

I also did a couple of WOT pulls, that brought the highest readings, which were off-scale on my small screen. I also did repeated "tap" tests (suggested by EODguy) on the MAF, from finger taps to semi-hard raps with a big screwdriver...the MAF never acknowledged it. I don't think it's the MAF. Or leaks, or O2 sensors, or anyting underhood.

Perhaps, I need to drop the shield over the FPR assembly, and see if there's a vacuum leak there.

[andrewwynn]

You can relieve the fuel rail pressure by unplugging the fuel pump fuse and running the car into it stalls if you need to connect with the Schrader valve stem removed.

On my e53, I was able to use valve caps from the wheels I've assumed the threads were the same and my kit came with a fitting that worked

[workingonit]

Originally Posted by andrewwynn

You can relieve the fuel rail pressure by unplugging the fuel pump fuse and running the car into it stalls if you need to connect with the Schrader valve stem removed.

On my e53, I was able to use valve caps from the wheels I've assumed the threads were the same and my kit came with a fitting that worked

I'll try removing the valve core, and also try running a 5/16"-24 tap into the M8-1 brass fitting, that nearly fits (it might just need thread cleaning, or the Schrader valve exterior might, too). From what I've read today, some manufacturers regard M8 and 5/16" as interchangeable, so I'll see how close they really are. And, I found a thread regarding the mystery surrounding the BMW Schrader valve adapter size https://xoutpost.com/bmw-sav-forums/...test-port.html.

I found it, and a reference to FCPEuro's fuel tester description for the CTA fuel pressure tester, which says it will work on BMWs "universally", not listing specific models, and the size of the mystery adapter as 5/16"x.308 (or slightly tighter than 5/16"-24).

[workingonit]

Originally Posted by workingonit

I'll try removing the valve core, and also try running a 5/16"-24 tap into the M8-1 brass fitting, that nearly fits (it might just need thread cleaning, or the Schrader valve exterior might, too). From what I've read today, some manufacturers regard M8 and 5/16" as interchangeable, so I'll see how close they really are. And, I found a thread regarding the mystery surrounding the BMW Schrader valve adapter size https://xoutpost.com/bmw-sav-forums/...test-port.html.

I found it, and a reference to FCPEuro's fuel tester description for the CTA fuel pressure tester, which says it will work on BMWs "universally", not listing specific models, and the size of the mystery adapter as 5/16"x.308 (or slightly tighter than 5/16"-24).
Attachment 82122

It may be that what I stated isn't entirely correct, but I'm operating in the dark, thru inexperience with BMW "mystery" specs, and a general lack of concrete facts being disseminated by those with the knowledge already. So, I've done more research, and an initial experiment today.

I found out that the US-standard Schrader valve (external) thread size is 5/16"-32 NEF, which uses an 8V1-32 tap (which, of course, I've never heard of nor have in my tap & die set). But, the Schrader valve on the fuel rail may or not be not US-standard, of course.

I haven't broken-out my tap & die set, yet, but grabbed my Slime 2410 Tire Repair Tackle Set (14-Piece Set)

from my pickup, and used the clean-up tool to chase internal threads on the M8 adapter #8 on the list/photo I posted, and used a TR416 tire valve stem (I have as a spare) as an in-house sustitute for the Schrader on the X5. I also tried screwing the #13 M8 adapter into the spare Schrader, after I removed its' core.


In each case, I could only get 2-3 threads to match-up (just like yesterday, when I tried adapter #8 on the X5). I hope that'll be enough to contain 50 psi fuel pressure, if I try either adapter on the BMW.

Also, I compared the "feel" of running the Slime tool over the external threads of the fuel pressure Schrader, compared to the "feel" of doing the same on the valve on the front, left tire...it felt about the same, with maybe a little more play on the fuel Schrader.

I'm also unsure whether I really want to remove the valve core (after removing the pump fuse, and running 'til dry). If I mess up the internal threads, using adapter #13, the core might not seal again (but, if I use the external adapter #8, then that shouldn't be a problem), and I wonder if running the fuel line dry will cause any loss-of-prime problem in the tank?

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.

[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.

[Effduration]

Do the early E53's have a different schrader valve ? As I noted earlier, I have Pittsburgh model 62623 ...Harbor Freight $ 14.97

It works fine on all my '03 - '06 BMW's

[X5chemist]

Interesting. I have the same kit. Now I'm curious. Unfortunately, mine is out of state for suspension and front end work. I'll have to check and test mine. With 154k miles, new pumps are on my maintenance list.

[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.

[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?