Aftermarket fuel pumps

**Mike WW** · 09-20-2021, 07:26 PM

Last year I replaced the fuel pump on my '98 328is with ~230K on it, just because I didn't want to get stuck with a dead pump. A whopping 3K later I ran out with 1/4 tank on the gauge. With the original pump I'd run it down below the bottom mark and had the light on with no issues. I chalked it up to cheap Chinesium parts, even though it was sort of a name brand. So I ordered a different one, Japanese by brand name and got exactly the same thing, made in China with the same hose and hose clamps that didn't fit.

So... what are you guys doing for replacement pumps? Or am I just lucky? I mean OE is crazy expensive and a fuel pump is not that sophisticated a device to justify the made in Germany, BMW brand price when it probably isn't even made there anymore!

**Eric93se** · 09-20-2021, 09:01 PM

Did you confirm the pump was dead after removing it? (put 12v briefly). I ask because running out of gas with 1/4 tank remaining is suspicious. I've had this happen when I first got my car and noticed how it sounded like it was not getting gas (would go but not accelerate) and just by adding some gas the car was fine again (first thing I tried). Learned about the siphon pump (drivers side) and investigated and found it was disconnected, reconnected it and may have put a nylon strap on it to hold together a bit better and never looked back. So check that.

Also for pumps and quality, VDO seems to be the minimum standard, rockauto has a couple that say they are VDO.

**brianc** · 09-20-2021, 11:25 PM

Yeah there’s a send unit under the drivers side back seat that sends fuel over to the passenger side… there’s a plastic tube that connects to this one and brings fuel over to the passenger side where the fuel pump is. Most likely there’s a problem w/ send unit or tube. As far as parts VDO is a good as it’s going to get, they’re OE BMW parts w/ the BMW scratched out.

**Mike WW** · 09-21-2021, 02:12 AM

I'm aware of the suction device on the drivers side, but I haven't been in there and it wasn't a problem before pump replacement. It was immediately after replacement that it started cranking ever so slightly longer before firing on startup. Not long, just not as near instantaneous, so I'm doubly focused on the pump. And it did start immediately with a gallon of gas added. It's possible the suction device came loose at the same time as I replaced the pump, people do win the lottery twice, I know a guy, but the odds are against it.

I haven't pulled the new pump, it works, it just won't draw down to a low level.

**importbanana** · 09-21-2021, 11:18 AM

Since you want to increase reliability, I would've simply bought a VDO pump and put it in the truck (+tools) and drive until the original one stops working.

I would've never removed the original working pump. For now, I'd buy a VDO pump and install it. If the quarter tank problem is gone, all good. If not, you can still deal with it then.

**Eric93se** · 09-21-2021, 01:18 PM

OK so maybe after you replace the pump a few more times you can check the siphon pump.

Adding a gallon and it starts working again is a good indicator the siphon pump disconnected.

**brianc** · 09-26-2021, 11:36 AM

Not sure if you fixed problem yet but I was getting my tank back in and figured would add some pics. If squatting in back seat facing rear of car this is what’s going on w/ the fuel tank..

C1EF0651-71CB-432A-8577-E80840F354E7.jpg

Blue fuel pump is on left, secondary sender is on the right. The tube attaches to sender and goes to a plastic baffle below the fuel pump. It’s not likely changing the fuel pump would damage the tube or sender on other side but the symptoms do sound like it.

Also you can see the VDO parts where the bmw logo is scratched out.

B0A189E3-BC1D-45AF-8309-E5E274E59011.jpeg DADB1A70-8833-451F-A4A3-F949ED00DD5E.jpg

**Mike WW** · 09-26-2021, 01:48 PM

Originally Posted by brianc

Not sure if you fixed problem yet but I was getting my tank back in and figured would add some pics. If squatting in back seat facing rear of car this is what’s going on w/ the fuel tank..

Blue fuel pump is on left, secondary sender is on the right. The tube attaches to sender and goes to a plastic baffle below the fuel pump. It’s not likely changing the fuel pump would damage the tube or sender on other side but the symptoms do sound like it.

Also you can see the VDO parts where the bmw logo is scratched out.

Thanks! I have not yet attacked it. I'm not putting a lot of miles on it currently and looking for that sweet spot of finding time to work on it and a low enough fuel level not to be spilling it everywhere. I have been thinking about that siphon tube, I don't remember seeing it when doing the pump, but I have slept once or twice in the year or so since I did swap it, so I may look at that before anything else.

**Ghost129er** · 09-27-2021, 12:52 AM

I get whatever my parts dealer gives me, got a VDO sender as nothing else was available but getting all sorts of other branded pumps, brymann, myele, etc, and never any issues with them, only issues with sensors or etc that made me THINK the pump stopped working but nope, all my Non-OEM pumps are great.

**importbanana** · 09-27-2021, 06:26 PM

Where do you live? What does AE stand for?

**Ghost129er** · 09-30-2021, 03:02 AM

Originally Posted by importbanana

Where do you live? What does AE stand for?

Dubai, United Arab Emirates

**Mike WW** · 11-03-2021, 10:22 PM

An update. Finally hit the mini lottery of time and near empty gas tank. Dug into the OBC and it said I had 21 L of fuel. Hotwired the fuel pump and pumped it into a gas can, running out at ~13 L. Pulled the drivers side sending unit etc and that side was near full. Which explained running out with 1/4 tank. Hooked up pump output to the suction side and it pumped right down. So the siphon works. Hmmm. Next I tried the suction side half out with the return hose pointed into the tank, not the suction device. Nothing. Apparently the new pump is so weak it can't push past the regulator. I'm surprised it runs as well as it does. It might be off a touch on power, but just a touch. Typically it starts after 2 engine revolutions instead of one like it did. Anyway, a Bosch from Autohausaz will be on the way shortly.

Rarely, but once in a while I'll get bit being a cheapskate, and this is one of those times. Oh well.

**importbanana** · 11-04-2021, 06:14 AM

This is with the chinese no-name product?

**Mike WW** · 11-04-2021, 01:26 PM

Originally Posted by importbanana

This is with the chinese no-name product?

Well, not entirely a no name pump, Spectra Premium, which makes a lot of stuff, or least has their name on it, and I thought was at least a so so brand. I bought another, this time GMB which is a respected Japanese brand I've gotten some very good products from in the past, but it's identical, and I mean identical to the Spectra pump.

**Eric93se** · 11-04-2021, 01:38 PM

Not following your logic on the siphon pump. It was connected properly or not.

**Mike WW** · 11-04-2021, 02:47 PM

Originally Posted by Eric93se

Not following your logic on the siphon pump. It was connected properly or not.

It was connected properly. I routed fuel from the pump output directly to the return line fitting on the drivers side assy and it started pumping down as soon as I powered up the pump. The siphon worked, but the pump was so weak nothing was coming out the return line with everything connected normally. The pump can't overcome the resistance of the 3.5 bar of the fuel pressure regulator.

**Eric93se** · 11-04-2021, 06:21 PM

Has the filter ever been replaced?

**Mike WW** · 11-04-2021, 08:56 PM

Originally Posted by Eric93se

Has the filter ever been replaced?

Not yet in my ownership, but it's on order. But it's not the problem. It could impede flow, but not pressure unless it was completely plugged, and it clearly has flow as the car runs and runs well. When I had the pump running, with fuel in the pump side, nothing, literally nothing, not a drop came out the return line. So it can't push hard enough to open up the diaphragm on the regulator. I should have put a gauge on it, I will when I replace it just to see.

**JDStrickland** · 11-05-2021, 03:21 AM

Originally Posted by Mike WW

Last year I replaced the fuel pump on my '98 328is with ~230K on it, just because I didn't want to get stuck with a dead pump. A whopping 3K later I ran out with 1/4 tank on the gauge. With the original pump I'd run it down below the bottom mark and had the light on with no issues. I chalked it up to cheap Chinesium parts, even though it was sort of a name brand. So I ordered a different one, Japanese by brand name and got exactly the same thing, made in China with the same hose and hose clamps that didn't fit.

So... what are you guys doing for replacement pumps? Or am I just lucky? I mean OE is crazy expensive and a fuel pump is not that sophisticated a device to justify the made in Germany, BMW brand price when it probably isn't even made there anymore!

Sucking air with 1/4 tank showing does not mean that the pump is bad, it means that the fuel level sending units are dirty. It could also mean that the siphon hose that pulls from the left side fuel lobe to the right side fuel lobe is not connected.

**Mike WW** · 11-05-2021, 01:15 PM

Originally Posted by JDStrickland

Sucking air with 1/4 tank showing does not mean that the pump is bad, it means that the fuel level sending units are dirty. It could also mean that the siphon hose that pulls from the left side fuel lobe to the right side fuel lobe is not connected.

Have you even read this thread? While I appreciate input, I'm so far past this it's really just an insulting reply.

**Mike WW** · 01-21-2022, 01:07 AM

A final follow up. I broke out my fuel pressure gauge and hooked it up. 38PSI. On a system rated at 51PSI. No wonder nothing was coming back thru the return line. Just for shi*** and giggles I threw in the GMB pump that looks exactly like the Spectra Premium (talk about a misnomer) pump, except for the part number stamped on it. Same part, same misformed hose that only fits on one end, same two Oetiker hose clamps of the same size for two different sized ends. Same exact thing. But this one pumps up to 51 PSI and pushes a bit thru the return line. I tried running it really low so the light would come on, but ran out of time and had to run errands so I filled it up. But the OBC showed it was down to 6.9 L, which is way lower than it was when it ran out. Starts faster, I swear it feels like it has more power, it's definitely better. Now how long it will last is another story, but we'll see.

Given that I'd bet a large amount of money both the Spectra Premium pump and the GMB pump came out of the same factory, I'd avoid either one, or one of the many look alikes like the proverbial plague. Now there's a bunch of Walbro and look alikes on ebay, they may or many not be good, but the Spectra Premium and GMB I'd run away from. YMMV.

**importbanana** · 01-21-2022, 02:51 AM

Why are you going through all that with your cheap pumps? Why don't you get a quality VDO pump which was OEM in this case and be done with it.

**Mike WW** · 01-21-2022, 03:20 AM

Originally Posted by importbanana

Why are you going through all that with your cheap pumps? Why don't you get a quality VDO pump which was OEM in this case and be done with it.

If I had known then what I know now...

And actually I did make a post inquiring about cheap pumps and didn't really get any good feedback.

20-20 hindsight is easy.

**importbanana** · 01-21-2022, 03:48 AM

I told you 4 months ago to get VDO.

**Mike WW** · 01-21-2022, 08:15 PM

Originally Posted by importbanana

I told you 4 months ago to get VDO.

#1. I bought the GMB long before that and figured I'd at least give it a try. The other one was clearly not right out of the box and this seemingly identical one is distinctly different.

#2. I don't just want to make things work right, I want to know why. It's just the way I am.

#3. I posted the follow up in the hope it might help others in the future.

#4. While I seek input here I have developed at best, a skeptical attitude about advice here. I seek advice and think about it, not just blindly follow what someone says. There's way to much misinformation in this forum not to do that.