DIY: Diagnosing and Replacing E46 Fuel Pump

[aurelius]

I did this for the first time recently on a family member's '02 325i @ 122k miles. Original factory pump with crimp clamp still on the hose.

Pump failure after about 2 miles of rough running on a very cold morning (< 20F) with 3/4 tank of gas. Would it have worked again in warmer weather? Maybe but the car was on the shoulder of a toll road and I had 24 hours to deal with it until towed.

A few things to add, based on my personal experience with this particular car.

As noted in post #29, I prefer the no-mess method of removing fuel pump fuse vs releasing pressure at the fuel rail. BUT...this won't work if your FP has already failed.

Round rubber grommet: don't slide along wiring - protective tape super sticky and it's a big mess when you go to slide it back in place.

Metal ring: seized in place. No idea why since it is not a metal on metal scenario but this ring wouldn't budge until I sprayed lube into all ridges and wait 10 min. WD40 worked for me. Save yourself a huge hassle and at least go get the small can of WD40 (make sure the straw is still taped to the can). Any convenience store probably has it.

As also noted in post 29, reinstall rubber O-ring INTO THE HOLE, NOT THE PUMP. I used a new O-ring but the original looked fine.

As for plugging the fuel line, I used plastic hose clamp pliers. Which worked fine but even though I released pressure at the fuel rail under the hood (as described in post #1), fuel was released when I removed the pliers from the hose. Therefore leave the pliers on the hose until the hose is pushed on to the new pump. Remember to slide the new hose clamp around the hose before fitting hose back to pump.

[gbvinatoru]

Hello ,

I encounter the same issue that many had but i haven't received any straight forward answer to solve my problem.

I have a 320d e46 (aka318d m47d20 115HP) that till now had starting issues when the engine was warm/working temperature.

All good, the issue disappeared when the error light was displaying . Had it checked and errors concern fuel pressure
The problems are the following:
-when it starts, it works fantastic, no interruptions, no surges of power all great
-when the error is present, it will start even at operating temperature
-for 1 week from now the car is refusing to start..at all, even when the engine is cold or warm

I have tried with different garages, specialist and it got worse: 1 of them replaced a injector and started smoking( black smoke-hence fuel mixture but not very much) and couldn't get in touch with the guy anymore to check the problem (long story)
-now, although it has the pressure error present it won't start

I confirm that the under the seat pump is new, filter should be new ( changed it last year).
I will also perform a injector check+calibration but the guy the issue is that the car is stuck at my parents, 150km away from me, a little town with 1-2 shady garages.

Did someone encountered similar problems as mine?Can the cause be the fuel pump from the fuel tank? I had it with all garages that don't know what they are doing i will investigate it myself. I would like first to take it home then try to sort the issue.

Other leads before changing all the fuel system ( just kidding) ?
I like the car but it's more than annoying not being able to use it whenever that i want.