fuel pump

0b1 · #1 10-21-2008, 05:22 AM

hi guys,

i'm a new member and a bmw fan as this is mah fourth bmw (2001 x5 3.0i black sapphire metalic). i had an issue with my final stage resistor and thx to you guys managed to do it myself. nuff thanks!

now i got an issue with my fuel pump i think, there's this weird whining sound coming from the back and now its so loud i can hear it in the cabin. when outside its loudest at the exhaust area of the car.

also when i start the car atimes there's dis poor combustion thing like the plugs are bad but i just changed the plugs and its still there, i have to keep the rev needle b/w 1 and 2 rpm for like like 3 minutes before she starts acting normally

can anyone verify if its the fuel pump cos the car is functioning properly otherwise and if it is is there a DIY for replacing it

Thx guys!

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The Cleaner · #2 10-21-2008, 02:20 PM

Is the check engine light on? any codes? In general the fuel pump will either work or not. Check for any intake leaks after the MAF.

X5Flyboy · #3 10-22-2008, 04:28 AM

my local indy told me to figure on replacing the fuel pump the same time I get the engine tuned up (ie, plugs,wires,etc) - he said the fuel pump accumulates "gunk" and the tune up interval of 100k miles is usually the life expectancy of the fuel pump

0b1 · #4 10-23-2008, 07:06 AM

the check light come on atimes but not that often, forgive my ignorance (this is my first millenium beemer so im kinda like a newbie) but can the codes be checked from the car itself or do i have to go to the dealer? (they're CRAZY expensive Here!) and hw do i check the MAF?

by the way its done 45k miles and any links to helpful DIYs will be much appreciated

thanx so much for ur time!

The Cleaner · #5 10-23-2008, 10:55 AM

You need the Codes to help diagnose, even if the light went off the code is stored. The code can be read from the OBD socket under the dash.

Fuel pumps are designed to kill themselves in the event of a problem to avoid overheating or a spark. That is not to say it's not possible to have a low volume pump, it's just not the norm. Most pumps are either working or not.

fast4d · #6 10-23-2008, 06:25 PM

check the fuel pressure at the schrader valve on the fuel rail on the intake.

ekvals · #7 10-23-2008, 07:15 PM

Quote:

Originally Posted by 0b1

hi guys,

i'm a new member and a bmw fan as this is mah fourth bmw (2001 x5 3.0i black sapphire metalic). i had an issue with my final stage resistor and thx to you guys managed to do it myself. nuff thanks!

now i got an issue with my fuel pump i think, there's this weird whining sound coming from the back and now its so loud i can hear it in the cabin. when outside its loudest at the exhaust area of the car.

also when i start the car atimes there's dis poor combustion thing like the plugs are bad but i just changed the plugs and its still there, i have to keep the rev needle b/w 1 and 2 rpm for like like 3 minutes before she starts acting normally

can anyone verify if its the fuel pump cos the car is functioning properly otherwise and if it is is there a DIY for replacing it

Thx guys!

I just discovered the same thig with my 2001 3.0 today...

I heard the whining sound as described.. When i went out of the car the sound got a lot louder on the right side of the car towards the aft.. I soon suspected the fuel pump.. I do not have any combusting problems or otherwise, but i guess its not supposed to make that sound and think maybe its about to fail..??

Weasel · #8 10-23-2008, 07:39 PM

A whine can be heard from the fuel pump at times when the fuel level is low, like when the light is on due to the lack of fluid around it to quiet it down. But not often. And often when the pump is going out it does lower its output, sometimes not noticeable at idle by gauge, but only when under load. What happens when the pressure is lower is that it will not atomize the fuel spray as well and it will run as if it were rich, yet be lean. If you have access to a fuel pressure tester and have any mechanical knowledge you can check it yourself pretty easily.

ekvals · #9 10-23-2008, 08:17 PM

Quote:

Originally Posted by weasel56

A whine can be heard from the fuel pump at times when the fuel level is low, like when the light is on due to the lack of fluid around it to quiet it down. But not often. And often when the pump is going out it does lower its output, sometimes not noticeable at idle by gauge, but only when under load. What happens when the pressure is lower is that it will not atomize the fuel spray as well and it will run as if it were rich, yet be lean. If you have access to a fuel pressure tester and have any mechanical knowledge you can check it yourself pretty easily.

I just filled the tank to maximum a couple of days ago, so i guess that cant be it..

Hmmmmm.. I guess ill have to check with a shop..

By the wayy... When i turn around the key in the ignition, the service engine soon is lighting up for a few seconds.. It goes away pretty fast and straight away when i start the engine.. Is this normal.?

Weasel · #10 10-23-2008, 09:22 PM

That is normal. When you first turn the key on the cluster turns on all the lights as a check. And with key on engine off the check engine, oil pressure and battery charge lights all stay on untill the engine is started. Nothing to wory about there.

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