Compatible Fuel Pressure Gauge?

[workingonit]

Originally Posted by Russianblue

So i ended up buying this kit.

https://www.amazon.com/dp/B00VV29NHM...sin_title&th=1

it's got a couple different M8 adapters that fit the fuel rail nipple 'pretty well' i sealed with some teflon tape and it seems to work. no leaks.

Running pressure is 51.5.
Engine off, immediate pressure is 45psi.
Then the pressure starts bleeding off. By morning it was at 5psi....

I bought an identical kit on Amazon, branded as Fekuar, and a $25 adapter with the correct Schrader valve thread ("305.32") match, that worked without Teflon tape.

My pressure readings were like yours, three years ago, on 5-11-22 (barely readingover 50psi, quickly dropping to 40+ engine off). But the engine continued to run fine, until the fuel pump eventually died (while being inspected last October '25), so I installed a new Hella pump, and tested again. This time using a better adapter, 2 for $13 (the first one lost an O-ring).

Pressure readings were 49.5psi/42psi engine on/off (odd, considering the pump should have been stronger than the old one, and the fact that the X was getting rich codes, not lean, which was the case with the old pump, for years). Following that test, the pressure gauge was left on the windshield for 22 hours before I tried starting the X , to observe the pressure on turns, the next day (never did that test). It read 36psi.

I bled the pressure, then started the engine, and it took about a minute for the needle to rise to 44psi, never reaching 50. I pushed the bleeder button again, got very little fuel from the bypass hose, and looked at the gauge again (after jumping back into the seat). It read ZERO. So, I tried again, with the same results, ZERO psi.

Then, I removed the gauge and extension hose from the gauge, and went through another round of key flip/clear codes/finally restarting, before I attached the fuel gauge to the fuel rail, sans extension. Still no pressure. WTF?

So, I bought a new gauge, a Performance Tool W80595, and will try again, after not testing for months (weather, health reasons). I did just run the engine a couple of days ago, for over thirty minutes, to monitor the fuel trims, MAF, and O2 sensor readings; all were as good or better than usual, so the fuel system MIGHT'VE gotten better after sitting months (maybe the problem I was having https://xoutpost.com/bmw-sav-forums/...inspected.htmlself corrected...fuel tank debris settling, plugged injectors/fuel line/FPR+filter cleared???).

Anyway, I'm about ready to drain and filter the fuel from the tank, replace the FPR+filter with a new Hengst unit, and test again. After my Dr. tells me if or not I need shoulder surgery, tomorrow.

Good Luck with your fuel pressure testing; I had no such luck with mine.