136K, fuel pump dead....?
 

So, over the past month or so I though I felt a slight hesitation on accelerating hard with the E53 but I put it down to being paranoid. Car ran without any issues otherwise.

A week ago I replaced my trans filter as it had been there for 40k with a lengthy pause 10k back when the engine was out for quite a while. Since the car was 10" raised I decided at that time to also swap my fuel filter as it probably had been in there for over 50k. Car was used for about 400 miles since this work was done.

This afternoon the car started fine but would not accelerate. I parked it and took another car to downtown DC. Got back and tried again with same result. Added about 15L of fuel, no improvement. Rather it got worse as it now cranks for a up to 5 seconds before the engine fires. Given that the filter is new, I presume my fuel pump has bitten the dust....

FCP offers a Bosch branded Pump/Sender unit for $198 which I feel tempted to buy. Anyone have experience with this unit? Given that this is 1/2 of the OEM pump and FCP's lifetime warranty, I think this is a reasonable alternative but I'd like to hear your thoughts?

136K, fuel pump dead....?
 

That is very similar symptom to wife's e53 when the FPR o-ring failed (40¢ part).

Rent or buy a fuel pressure gauge and test the pressure.

If the pressure "jiggles" eg bounces bewteen 49-50 (usually so fast makes the needle fat/fuzzy looking) FPR not working properly.

Other symptom is pressure won't hold.

If pressure drops after power off and is zero overnight it's almost for sure FPR.

That said, fuel pump avg life is 5000-6000 hours. divide odo by 5500 and compare to your average mph. If your mph avg is lower than that # your pump is over due for failure.

The FPR's job is to disguise a failing fuel pump.

At end of life for the last year or two the fuel pump gets weaker and weaker and that is completely masked by the FPR.

Eg: new pump may output 60 psi, the engine gets 50 and 10 goes back to the fuel tank. When the pump is almost dead it will output 52 psi and 2 goes back to tank and 50 goes to the motor.

You may see power loss at WOT when the pump output drops below 50 so the engine can't get 50.

The fuel filter is a "lifetime" filter good for 400-600k mi. So yes after 50k, it's only getting warmed up.

Most people reeplace the filter/FPR when the 40¢ o-ring between filter and FPR fails. The filter is likely less than half worn out at this point.

136000/5000=27.2 136000/6000=22.6

Your average mph should be between those two values if your pump is shot.

I would have no problem with any FCP OEM pump.

They are 5/10 difficulty to replace.

While in there: fix the o-ring on the siphon jet as it should be failed or close to it by now.

Mine is an 06/03 build and I think the FPR is integrated in the filter. I'm going to buy the Bosch unit and see how it goes. On an '06 I once owned the pump died at 70k, so I'm still ahead with this one. While waiting for the new fuel pump to arrive, I will do the drive shaft boots and the injector O-rings.

This afternoon I went ahead and removed the sea of plastic covers on the engine, all the quick-ties holding the wiring and the fan/shroud. Tomorrow I'm tied up most of the morning but I should be able to find time to take the stiffener plate off and disconnect the starter wire and the oil level wire. With a bit of luck I can get the O-rings and the drive shaft boots done by Thursday evening. In all I expect the car to be laid up for the week....

On Friday I promised to do a set of drive shaft boots on a friend's GL class that I host while he is overseas. (Very similar suspension set-up to an E70 there :) ) No shortage of projects this week!

My first pump lasted 10 years and around 100k. Since I’m tearing my 2002 X5 4.4 apart anyway (I figured a new one was clear insurance, so I bought a Delphi pump. The price was better than Bosch and I figured as Delphi is a tier one supplier I’d be ok. Wish me luck.

My plan is to yank my pump while the car is out of service for the motor swap and keep my old one as a spare. The jet o ring is great tipper, so I’ll do that too.

You only need the actual pump as a spare you can put it in a Ziploc bag and stored in the back


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400-600k for a fuel filter??? I mean, yeah, gas is a lot cleaner than it used to be. And yeah, plastic tanks make for cleaner fuel. But I think that's a bit generous.

Also, fuel filters are cheap and easy to replace. I can't imagine pulling the fuel filter off to replace an o-ring and not replacing it.

Today injector o-rings and vibration damper replaced.
 

This morning got back home earlier than expected and tore in to the E53. Got the stiffening plate off to disconnect the wiring under the motor. (Noted that the driver's side CV boot just started to lose some grease. Good job I got replacements already.) Then disconnected all the wiring on the front of the engine. Next was disconnecting the wires from the coil packs. At last after all the deconstruction lifted the fuel rail. Removed all the injectors and replaced the o-rings. Of course managed to spill a bunch of gas....not a job for anyone who dislikes fuel vapor!

The injector connectors are held in place by horribly thin wire clips. No idea how some remove those without lifting the fuel rail first?! If you drop one of these, forget about finding that again... The wiring boxes need to be loosened to pull the connectors clear from the injectors. Then there are clips holding the injectors to the fuel rail which come off pretty easily. The old o-rings were not too bad, bottom ones hardened, top ones softer than new. I lubricated the new o-rings and put them back on the rail, then reassembled the top of the engine. Reconnected all the wiring and tied it down. There are about a dozen wires for all the kit on the front of the engine: Vanos, thermostat, tank breather, alternator, etc, etc. See pics below of the rail and the clips.

Next was a replacement vibration damper. The old one chirped and seemed a bit out of round but that seems odd for such a heavy piece... (Anyhow, the result was good, no more chirping :-). ) Popped the fan back in and connected the air intake. After cranking for half a second it fired right up and purred like a kitten. Very happy to have this out of the way. There is a lot of stuff that needs to be removed to get the fuel rail off. :-(

Tomorrow, next step is to pull the LH drive shaft and replace inner and outer boots. The RH one may have to wait a few more days as I'm almost out of grease for the inner CV, it will be a few days before I get a few more tubes in the mail. Hopefully the new fuel pump hits the mat on Wednesday.

136K, fuel pump dead....?
 

The filter I cut in half at 180,000 miles EASILY had 50% life.

Consider the tiny inline filters of yesteryear could last 10-20,000 miles and were maybe 1/10 the lengrh and 1/10 the width. That means 10x10x10 or 1000x the filter media so yes: lifetime.

The inlet side of the filter media was FILTHY! Like squid ink black but the outlet side looked new and there was no visible film and no sign of flow restriction.

My original filter is at 203k mi. and I see no need to replace preemptively. When I'm "in the area" I will pull it open and replace the o-ring that is the normal failure mode of the FPR.

I bought a new FPR+ filter using the same logic about not expensive enough not to however during postmortem discover that the $65 FPR/filter were perfectly ok but the 40¢ o-ring was shot.

$65 is a decent meal out with the wife. (Also I've come up with half a dozen pennies on the dollar repair for e53; example: 17¢ fix for $230 disa or $12 fix for $225 door lock actuator or 40¢ fix for $65 FPR or 40¢ fix for $90 fuel sender unit.

The DLA fix alone saved $872 on wife's e53. So yeah; partly because I'm just used to fix vs. repair even the not so expensive jobs get the cheap route.

Did not pan out as expected.
 

Last week got the boots on the half shafts done. Was pretty easy as I pulled the tripods out and worked from the inboard end.

On Wednesday the fuel pump fell on the mat and I got it in the car Friday morning. Improvement! However.....still could not get the engine to rev over 4000 rpm. Had a lean mixture code pop up as well. When this issue popped up I could hardly rev over 1500 rpm. I had considered right at the beginning that the new filter might be the culprit. My suspicion was still on the new Hengst filter.

Immediately ordered a Mahle filter which came overnight and found time on Sunday to get it mounted. (Thoroughly hate the way the under-body panel has to be dropped to get at the filter....aaaargh.) Started it up as soon as I had the lines connected to the filter and it started quickly and easily. Success!! Car responds crisply to throttle inputs and revs to the red-line no problem!

A bit of a stupid saga due only to a faulty replacement part but I guess I'm happy with the way it came out.