In praise of Delphi fuel pump
 

I have to say I am pretty impressed (so far) with the Delphi fuel pump! It is smaller than the TI, which had me a bit worried at first but seems to be working VERY well. The check valve is holding better/longer and I am noticing quicker starts, it's pretty much silent and hopefully the carbon commutator proves to be a bonus and I live long enough to tell about it! ;)

I had good luck with them. My premium Bosch was DOA found out too late to exchange grrrr.

Maybe less praise today after fixing burnt wiring connector! ;( Probably partly my fault for not putting any contact grease on the connector when I installed the pump a while back but power wire connection now failed. The wires (and likely the contact pins) don't look like they are probably the best quality, or it could be 20 year old connector with no contact grease or some combination but had to deal with that today. Really lucky that the car quit in the driveway though! ;)

Dang, next on preventative maintenance list: new fuel pump.

Between 20 some year old connectors with maybe seals that are no longer that great and maybe the mating surface on the pump side isn't perfect, I would at least definitely use some contact grease. It seems to be a known issue even from the factory and sooner with the E70 so I went with wiring everything direct on the E53, you need to make sure you get a good seal on the wires though or you'll get a CEL for tank leakage! Tank leakage code might also be a hint to maybe having a melting connector issue! ;)

Did you replace the syphon side too? I'm debating on doing both sides or just the fuel pump. I never let mine under half a tank. Rarely to 1/4 tank.

I didn't replace the fuel pump this time, just fixed the wiring. I fixed up the syphon side a long time ago but I did check it and all is still good! ;) The syphon comes into play somewhere around 25-30 liters so could leave you stranded before a 1/4 tank. The syphon leaking also can lower your engine running pressure so best to have that sealed up! ;)

Interesting, I didn’t realize the syphon/sender unit could lower fuel pressure….makes sense tho. I should check my pressure now after replacing the sender a few months ago. I put a Delphi pump in several years ago and have been noting about 40 psi at the rail. I think it should be 50?

Yes, I think 50 ish (46 ish stopped) psi is normal but the gauge can be a big factor.
The "pump running" pressure will be higher because the syphon jet creates back pressure on the regulator. Pump "just stopped" will show the pressure regulator setting. The poor wiring connection (sender/holder connector) can be a big problem. I know the fuel pump connector has turned up as a problem on this forum a few times, I just wonder how common it is, and if the Delphi pump connector is a contributing factor ??

Update: Now my "direct wired" pump failed again, and in the driveway again! Haven't got it apart yet but I wouldn't be surprised if the big voltage drop across the old connector was really hard on the pump and now it gave out completely. My son on the extreme end of the Autism spectrum sometimes spends a lot of time in the car with engine idling idling on the driveway so that is why it was in the driveway both times that it quit! ;) Could be that the engine idling with the A/C and headlights on dropped the voltage, increased load/heat and pushed the pump over the edge. A partly plugged fuel filter could be adding to it as well, I changed it once I think around the 250k km but not since with 498K km now.

The fuel goes in circles pretty fast when at idle. I would suspect fuel temp getting pretty warm being involved.

Will it come back to life if you apply voltage directly?

The fuel coming back to the siphon jet was crazy fast when I had it open enough to see it was leaking and it sprayed like a garden hose.

The quantity of fuel in the tank is the heat sink to cool the recirculating fuel so if low on fuel that will be related.

Geeze I hate when that happens! Fuel pump arrived today and it turned out to be a cheap Spectra pump in the Delphi box! Rock Auto wants it back too so that sucks even more. They used to be easier to deal with but the automated 'report a problem' doesn't take some things into account. I guess I will do the return, order the Delphi again and cross my fingers that it's NOT another Spectra pump! Maybe this has something to with why the Delphi units were on sale for so cheap a while back ?? Anyone order one of those??

Ouch! I ordered an "a-premium" so i could get it overnight and it worked for 11 months.

I was out of town when they said they needed a photo to get a warranty replacement but i was able to get my dad to find the part and take a photo.

The replacement lasted for the rest of the life of the car.

Warehouse swap? Return? If you get another bad one, I'm going to order a Hella.

I'm going to take it apart and have a better look at what's going on, maybe do some voltage drop/current draw and pressure measurements. I have a feeling that I might have to order the complete Delphi assembly again to get the Delphi pump. I'm not sure the Delphi pump will fit into the stock tank unit so that would explain some things so I'll have a look at that too. I wish I could remember for sure what pump (I think it was a Pierburg) I used when I did the replacement at around the 200k mark because I took that one apart at about 400k when I put in the Delphi as preventative maintenance and it still looked like new, almost no wear at all, and probably would have lasted the rest of the life of the vehicle.
BTW one pin on the connector for the Hella assembly looks like it's already oxidized in the RockAuto pic!

So I did a quick voltage drop and current draw and pump is only drawing 6 amps so I am suspecting the pump might be worn out. I'll do some more checking/pressure test to get a better picture but I might not be ordering another Delphi pump! The Rock Auto pic of the Delphi pump by itself now shows brown end caps on the pump same as the Spectra pump that was in the box and NOT the black end caps that the original Delphi pump has so might be something fishy going on!
It's funny (probably AI) that I had to say that I already installed the pump in order for my problem to accepted as "boxed wrong" otherwise it always came up with "we will only accept an original Delphi pump in return." I had another crazy AI thing come up before I ran into that which is why I even got the idea to switch up my input to try to get the proper response!

So I ordered the Pierburg pump and while waiting did a pressure test on the Delphi and sure enough only about 60 PSI head pressure and pump makes an awful sound at that point so looks like the pumping elements are worn out and I was fooled a bit by the burnt connector. Delphi bragged about having made the motor better, and the check valve seemed to hold nicely too but I guess that doesn't matter much if the pumping elements are still a weak link.

Don't drop the pump! I bought a pierburg and dropped it about a foot to the ground just before installing and killed it!

Do you know what the normal head pressure is on these pumps?

I've seen anywhere between 70 and 120 PSI, I would expect at least 70 if rail pressure is in the 50s.

Thanks! I've been looking for that info for years impossible to find!

What a cluster fukk! Of course the Delphi holder assembly is made differently (the pump is smaller and the isolators are at an angle which is maybe better for noise) so only the Delphi pump fits into it and the Delphi pump, when ordered by itself, is to fit in the stock holder which is maybe why they put the Spectra pump in the box! So I don't how a person would get a replacement Delphi pump to fit in the Delphi holder, not that I would want another one, so yeah I withdraw my praise and replace it with criticism!

I had to reengineer the assembly to hold a Bosch pump i think they changed the design of the sender assembly and the newer pump style is not a drop in. What year is your car? Might be helpful to know for the next guy.

So the Pierburg pump is the smaller diameter (comes with adapter for the stock hanger) to fit the Delphi hanger BUT shorter so the hose wouldn't be quite long enough! So I installed the Pierburg pump in the original hanger with the included adapter, fixed up and reinstalled the original harness connector and installed that. Works well, nice and quiet, BUT doesn't hold pressure at all as if there is no check valve! I have a OE BMW pump and hanger in my cart and I think I might just pull the trigger on that and then keep the either keep the Pierburg as a spare or return that one too and maybe put a Bosch pump only into the original hanger, haven't made up my mind yet! Geeze!

So I picked up a used pump assembly from a wrecker and have that installed and working. I'm going to send the Pierburg pump back, but I'm wondering if it wasn't leaking from the internal hose. I was hoping that maybe not holding pressure would help with my slightly leaking injector/flooding after 2 or 3 days problem but it made no difference. The supplied clamp and line don't seem to work well together and looks almost like the line was distorted by the clamp to allow a bit of a leak. If I had more time and money I would probably eat the cost of the Pierburg (I had to pay 20 some dollars return shipping this time!) and take it apart to see if being so small it is maybe brushless ?? I now have a new BOSCH (TI) installed on the original hanger so that is what I'm going to use now (back to using the connector instead of direct wiring) with the used one as a spare.

sort out the differences in fuel pump replacements, please
 

80stech and andrewwynne: As I'm probably going to order a new aftermarket fuel pump for my '01 X5 pretty soon https://xoutpost.com/bmw-sav-forums/...inspected.html (after I further test mine outside the tank...if it's possible that the pump won't run if the fuel filter is completely clogged, then I have to investigate it); this thread has made it seem impossible to choose a pump, since I don't know if I'll have to adapt one brand of pump to fit into the holder or not, and it looks like nobody has a go-to pump they'd recommend. Plus, since mine is a 7/2001 build, has anyone ever changed out a pre-facelift pump?

Off-hand, I would've assumed that Hella and Pierburg would be OK for BMW's, and since I've been mainly a General Motors afficionado for 60 years, the AC Delco (and the modern Delphi brand) have positive connotations to me.

Whatever pump I order, I sure don't want to have to pull it out immediately due to some unforesaaen failure, nor do I want to have to re-engineer a pump to fit in my X (I've done WAY too much redneck engineering in my day...I want a plug & play solution the first time). Talk to me about this, please!

Don't test then pump outside the tank, can be dangerous! The pump will run with the filter completely plugged so that's not a problem. The Bosch pump is the one to get if you want to replace just the pump. If you want the whole unit it might be best to pay the price for the OE. Looks like no difference for facelift or not with the fuel pump??

In my thread, I said I was going to test the pump in a bucket, but that was before I read your comment here. The filter is who knows how old, but the fuel pressure regulator part is only about 3k miles old.

I can't find a Bosch pump for my '01 X5 online, and I've looked at FCP, ECS, and RockAuto.

Rock Auto and FCP both have the Bosch pump. I don't think there is a difference between facelift and not, FCP lists the same for both. If you want drop-in with least amount of chance for something to go wrong then go with the OE assembly.

is cheap not compatible with BMW?
 

I clicked on the greyed line "Fuel Pump and Housing Assembly" on RockAuto, which didn't show Bosch, nor did FCP when I searched for the same part. I don't want a pump insert, which doesn't address the rest of the assembly (my fuel gauge has been a bit wonky, twice, so I'm sure I need the sender part. I need a "one and done" complete assembly.

However, being on a low to no budget (why did I want a BMW, then? you might say), I'm shopping for a complete assembly for under $200 (it seems everything I buy, including my cellphones, now must conform to that figure, per my CFO). Looks like i may be getting a Hella, or at worst, a Uro unit.