Knowing when to replace the old fuel pump

[sapote]

Mine failed without warning, though thankfully not on the side of the road. Parked the car one night and the next day it wouldn't start. Want to say I was at around 120k miles at the time.

If it hasn't driven with a new pump, could you read out the individual fuel volume in each tank please? I really want to confirm my theory.

[terra]

If it hasn't driven with a new pump, could you read out the individual fuel volume in each tank please? I really want to confirm my theory.

This was years ago, sorry

[sc_tr0jan_m3]

My track car just clocked over 100k and on the track I noticed the usual fuel starvation happening on long right handers... but I noticed that more and more that sputtering feeling would happen when the gauge would read half tank. Sure enough one morning while driving to the track and with 1/3 of gas left in the tank, I felt the sputtering of the engine when I was on the freeway and I immediately pulled into a gas station and filled up to see if it'd go away. After that experience I just did a full overhaul of the fuel system and thankfully all that's gone away.

[WoGGo]

Easy to check the hidden display than hook up the fuel gauge.

Could you explain how to do this, or link us to a guide?

[sapote]

Could you explain how to do this, or link us to a guide?

https://www.bmw-driver.net/threads/diy-e46-hidden-obc-functions.31204/

Function 6.0 displays the 2 fuel tanks.

[sapote]

My track car just clocked over 100k and on the track I noticed the usual fuel starvation happening on long right handers...y.

Makes sense, as the right tank was lower than the left tank with a worn out weak pump.

[maw1124]

https://www.bmw-driver.net/threads/diy-e46-hidden-obc-functions.31204/

Function 6.0 displays the 2 fuel tanks.

Off topic, how do you like that site?

maw

[ac427]

That’s the internal check valve. Goes out early when cars sit and moisture in tank ruins it.

Is the check valve inside the actual pump or part of the cradle?

[sapote]

Is the check valve inside the actual pump or part of the cradle?

I believe CV is inside the pump.

[old///MFanatic]

Is the check valve inside the actual pump or part of the cradle?

Internal. Back in my E30 M3 days BMW parts had a $12 external check valve you could run inline if a valve was giving issues. Not sure if it’s even still available or worthwhile.

[sapote]

If the CV is leaking, I would just time the pump prime period then crank the engine before the prime ended. Once engine is running, it doesn't matter with the CV.

[LSB4Me]

Curious—is replacing the fuel pump a big job and when is the convenient time to change it?

I have a valve adjustment coming up along with some other small stuff and think it might be time to replace the 04 OE pump.

[old///MFanatic]

Curious—is replacing the fuel pump a big job and when is the convenient time to change it?
I have a valve adjustment coming up along with some other small stuff and think it might be time to replace the 04 OE pump.

It is actually a pretty easy job.
As for when is it convenient, when you have less than 1/4 tank.

[BCEXP]

Want to know when to replace the fuel pump? Drive your car until the pump just gives up and you get stranded in the middle of a busy street. Ask how I know lol

YUP! Happened to me twice. Now I just replace my pump every two years. While the factory pumps have good performance, they have not been reliable for me.

[LSB4Me]

It is actually a pretty easy job.
As for when is it convenient, when you have less than 1/4 tank.

Bit of a silly question, but where is it? Sounds like it’s under the hood on the passenger side, but I can’t be sure.