In-tank Fuel Pump Modification

E28 technical advice asked and given! Troubleshooting, modifications and more.
Ju@n
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Re: In-tank Fuel Pump Modification

Post by Ju@n »

cek wrote:Oops, I did it again...

I needed to do this on my 528e (Maytag) and since this is the third time I've done one of these I figured I'd take more pictures and share additional details.

Recall, the idea here is to replace the prone-to-fail in-tank "transfer pump" with a modern, high-performance pump. By doing this you also will delete the main fuel pump that sits by the right rear wheel next to the fuel filter.

You'll need the following:
  • Your original OEM in-tank fuel pump hanger assembly.
  • Several feet of 12x18 BMW fuel line
  • Several feet of 8x13 BMW fuel line
  • Soldiering iron
  • A TRE "TRE-340" 255 LPH fuel pump (~$79 shipped)
Image

Assembly is easy.

First, take the original rubber connector that goes from the original transfer pump and cut it in half, where the smaller diameter section meets the larger diameter section.You'll use the smaller diameter piece INSIDE your 12x13 tubing to step the size down.

Cut the smaller section into two peices, approximately as shown:
Image

The shorter piece will step down the connector you'll make between the new TRE pump and your hanger. The length of this piece is pretty critical because it is what will determine the overall length of your pump/hanger, enabling the little filter on the bottom of the pump to be all they way at the bottom of your tank.
Image

Image

Slide this over the output nipple on the TRE pump. Slide the other end over the input nipple on the hanger.
Image

Before clamping double check the overall height. In this picture I determined my height was too tall, so I used the shorter piece of tubing you see in the picture above, making it just right.

Get out your soldering iron and de-solder the old power lead. Then cut the new lead to length and solder it in. Solder a new eye-clamp to the ground wire, after cutting to length and use the screw that was already there to affix it.

Use hose clamps (I prefer Oetiker clamps because they are much smaller and make getting the pump into the tank easier).
Image

Make sure the filter is oriented right. Use the original pump as a guide. You want it pointing the opposite direction as the vent inlet nipple on the top of the hanger.

When installing the hanger, be VERY careful because the rubber condom that comes with the TRE pump is fragile and can easily tear.

Under the car you need to remove the original main pump, filter, and hanger assembly.

Tie off the power wires for the original pump and seal the ends up so they don't short out. They'll never be used again.

Use the other piece of tubing you salvaged from the old in-tank pump to size-reduce the 12x18 line coming from your tank to the filter.

Use a piece of 8x13 to curl around out of the filter output to the nipple for the hard-line that goes to the engine bay.

Image

Re-hang the filter, selling the old main pump to someone who, for some strange reason doesn't want to do this awesome upgrade.
This should be stickied! :D
cek
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Re: In-tank Fuel Pump Modification

Post by cek »

Dub-Nub wrote: How old is the oldest pump you have that is TRE and is it loud? I have replaced my external with a new one last year and my internal with Intrex (the cheap versa version) but internal one is making a lot of noise again and getting tired of it. I like the idea of one pump and am interested in this conversion.
I had to read this 4 times to understand what you were asking, BTW...

I put the TRE in Vlad 3/27/2016 @ 189,756 miles.

The car now has ~195,500. Still quiet. The Walbro got loud right away.
Dub-Nub
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Re: In-tank Fuel Pump Modification

Post by Dub-Nub »

cek wrote:
Dub-Nub wrote: How old is the oldest pump you have that is TRE and is it loud? I have replaced my external with a new one last year and my internal with Intrex (the cheap versa version) but internal one is making a lot of noise again and getting tired of it. I like the idea of one pump and am interested in this conversion.
I had to read this 4 times to understand what you were asking, BTW...

I put the TRE in Vlad 3/27/2016 @ 189,756 miles.

The car now has ~195,500. Still quiet. The Walbro got loud right away.

haha sorry. Thanks for the answer.
1st 5er
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Re: In-tank Fuel Pump Modification

Post by 1st 5er »

I've been running Tre's since 2012 w/o issues.
jhall
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Re: In-tank Fuel Pump Modification

Post by jhall »

Ordered a TRE this morning after reading through this thread. Order placed at 11:53 am cst (gods time), shipping notice with tracking number received at 12:12 pm. I'm impressed.

Thank you for the step by step instructions cek, hope it goes as easy and clean as you make it look. Wish me luck.
Skywalker_Andretti
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Re: In-tank Fuel Pump Modification

Post by Skywalker_Andretti »

This thread is quite amazing and imformative. As many others, I'm currently in the process of doing this mod as my main in-line pump is giving out and my in-tank pump has been dead for who knows how long on my 1983 533i.

I was seriously just going to buy a new airtex pump on amazon but after reading enough to turn me off from that and deciding the TRE route, which I would install the TRE-340 I believe, the ONLY question I have is, do you literally just put the new pump in and that's it? Keep the filter in and be done with it?The stock fuel pressure regulator handles the rest?? Thank you guys you are all a godsend :D :cool:
cek
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Re: In-tank Fuel Pump Modification

Post by cek »

Skywalker_Andretti wrote:This thread is quite amazing and imformative. As many others, I'm currently in the process of doing this mod as my main in-line pump is giving out and my in-tank pump has been dead for who knows how long on my 1983 533i.

I was seriously just going to buy a new airtex pump on amazon but after reading enough to turn me off from that and deciding the TRE route, which I would install the TRE-340 I believe, the ONLY question I have is, do you literally just put the new pump in and that's it? Keep the filter in and be done with it?The stock fuel pressure regulator handles the rest?? Thank you guys you are all a godsend :D :cool:
Yep, besides bypassing the old under-car pump no other mods are needed.
Skywalker_Andretti
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Re: In-tank Fuel Pump Modification

Post by Skywalker_Andretti »

cek wrote:
Skywalker_Andretti wrote:This thread is quite amazing and imformative. As many others, I'm currently in the process of doing this mod as my main in-line pump is giving out and my in-tank pump has been dead for who knows how long on my 1983 533i.

I was seriously just going to buy a new airtex pump on amazon but after reading enough to turn me off from that and deciding the TRE route, which I would install the TRE-340 I believe, the ONLY question I have is, do you literally just put the new pump in and that's it? Keep the filter in and be done with it?The stock fuel pressure regulator handles the rest?? Thank you guys you are all a godsend :D :cool:
Yep, besides bypassing the old under-car pump no other mods are needed.
Awesome. And as I was on the website I noticed they had so many different options for what cars are compatible with the TRE-340 pump and yet they were all the same, basicly implying they are all universal? Clearly it doesn't matter which one I purchase as long as its the 340 pump, correct?
proto17
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Re: In-tank Fuel Pump Modification

Post by proto17 »

I tried this over the weekend and was never able to get a hose clamp on the pump nipple to keep the whole thing from falling off if I hit a bump. Maybe I'm being too worrisome about it. Here are some pics (sorry, only Google Drive links) of what I'm talking about.

This picture (https://drive.google.com/open?id=0BzpbY ... mtTeFRUWGc) shows why I can't get any kind of hose clamp in there. I assume that the clamp needs to be firmly seated over at least half of the little piece of fuel line used as an adapter in order to not actively be pushing the adapter away from the 12x18 hose.

Here is a picture (https://drive.google.com/open?id=0BzpbY ... 0w4azVpVUU) of how small the little piece of hose is. The only way to get a hose clamp on would end up with the clamp actually 90% above the thing it's supposed to be clamping down on.

It should be noted that I am using standard size fuel line (1/4" and 1/2" I think) since I don't have any sources of metric line that's safe for in tank use. I did attempt to use the line that goes from the tank to the outboard pump, but the difference is outer diameter is virtually nil for this purpose.

Any thoughts? Just put some clamps on there and move on?

Thanks!
cek
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Re: In-tank Fuel Pump Modification

Post by cek »

proto17 wrote:I tried this over the weekend and was never able to get a hose clamp on the pump nipple to keep the whole thing from falling off if I hit a bump. Maybe I'm being too worrisome about it. Here are some pics (sorry, only Google Drive links) of what I'm talking about.

This picture (https://drive.google.com/open?id=0BzpbY ... mtTeFRUWGc) shows why I can't get any kind of hose clamp in there. I assume that the clamp needs to be firmly seated over at least half of the little piece of fuel line used as an adapter in order to not actively be pushing the adapter away from the 12x18 hose.

Here is a picture (https://drive.google.com/open?id=0BzpbY ... 0w4azVpVUU) of how small the little piece of hose is. The only way to get a hose clamp on would end up with the clamp actually 90% above the thing it's supposed to be clamping down on.

It should be noted that I am using standard size fuel line (1/4" and 1/2" I think) since I don't have any sources of metric line that's safe for in tank use. I did attempt to use the line that goes from the tank to the outboard pump, but the difference is outer diameter is virtually nil for this purpose.

Any thoughts? Just put some clamps on there and move on?

Thanks!

From above:
Use hose clamps (I prefer Oetiker clamps because they are much smaller and make getting the pump into the tank easier).
Image
Also: If you do this right the pump will rest on the bottom of the tank with the upper part PUSHING it down to the bottom of the tank. Preventing the hose from slipping.
proto17
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Re: In-tank Fuel Pump Modification

Post by proto17 »

I forgot to add that I had ordered some of those smaller clamps. I didn't realize that it actually touched the bottom of the tank. That makes things a lot easier. Thank you!!
cek
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Re: In-tank Fuel Pump Modification

Post by cek »

proto17 wrote:I forgot to add that I had ordered some of those smaller clamps. I didn't realize that it actually touched the bottom of the tank. That makes things a lot easier. Thank you!!
Yes. Note the tube that connects the pump to the hanger is sized (length) just right such that it abuts against the cross tube on the hanger? In my example photo it's not QUITE right, but close. What you want is the overall length of the entire unit to be such that when you set it in the tank there's no way that tube can pop off. It is the length of that piece of tube that determines this.
proto17
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Re: In-tank Fuel Pump Modification

Post by proto17 »

Awesome :) Thank you very much for the explanation!
Dake
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Re: In-tank Fuel Pump Modification

Post by Dake »

The pump I bought to do this modification is a 320lph instead of a 255lph. It is because I got ahead of myself while reading through this thread and apparently model names have nothing to do with LPH rates. Lesson learned.

Will that cause problems? Running rich? I really don't want the hassle of returning this 320 if I don't have to. Thanks.
Last edited by Dake on Jan 05, 2018 5:33 PM, edited 1 time in total.
cek
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Re: In-tank Fuel Pump Modification

Post by cek »

Dake wrote:The pump I bought to do this modification is a 320lph instead of a 255lph. Will that cause problems? Running rich? Thanks.
The FPR will protect against running rich. I think it'll be fine as long as your fuel hoses and clamps are in good shape. Which exact pump did you get?
Dake
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Re: In-tank Fuel Pump Modification

Post by Dake »

cek wrote:
Dake wrote:The pump I bought to do this modification is a 320lph instead of a 255lph. Will that cause problems? Running rich? Thanks.
The FPR will protect against running rich. I think it'll be fine as long as your fuel hoses and clamps are in good shape. Which exact pump did you get?

This AEM pump.

https://www.amazon.com/AEM-50-1215-E85- ... 016MWXRK4/

I edited my post just as you replied, but TLDR I'd be really happy to not have to go through a return process, I just don't want to hurt anything or set myself up for a failed pump down the road.
cek
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Re: In-tank Fuel Pump Modification

Post by cek »

I'm no expert in fuel pressure, but given high quality fuel hoses are all the same across cars, even those with bigger fuel needs, I don't think it'll be a problem.
Crazy_Canuck
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Re: In-tank Fuel Pump Modification

Post by Crazy_Canuck »

cek wrote:I'm no expert in fuel pressure, but given high quality fuel hoses are all the same across cars, even those with bigger fuel needs, I don't think it'll be a problem.
Submersible fuel line rated to SAE J30R10 has a minimum burst pressure of 2.8 MPa (406 psi) for 13mm ID hose, up to 3.4 MPa (493 psi) for 6mm ID hose.
Dake
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Re: In-tank Fuel Pump Modification

Post by Dake »

Guys, I opted to return the pump I bought in my previous post. I decided to do it by the book and I ordered this exact pump from TRE:

- https://treperformance.com/i-656-bmw-25 ... odels.html

When I unboxed it, it doesn't say TRE anywhere on it, it doesn't have the large black rubber cover, and in fact says Walboro on it. It looks the exact same as the pump at the top of Page 5 in this thread, which is supposedly the TRE in-house pump, and it actually doesn't look like the Walboro they have on their site:

- https://treperformance.com/i-133255-uni ... -pump.html

Here's the one I got.

Image

But it IS the exact model Walboro GSS 340 found for $76.50 on Walboro's site:

- http://walbrofuelpumps.com/255lph-walbr ... -pump.html

Image

So are they not branding their own pumps anymore? Did they make a mistake?

More immediately, is the one they sent me the loud one everyone talked about in this thread? If not I'm just going to install it.

Link to images https://imgur.com/a/xbftB
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Re: In-tank Fuel Pump Modification

Post by cek »

That's lame.
SlickDizzy
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Re: In-tank Fuel Pump Modification

Post by SlickDizzy »

I would e-mail TRE and see what they say.

I was just about to order one of these, hopefully they aren't just sending out Walbros now...
Dake
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Re: In-tank Fuel Pump Modification

Post by Dake »

SlickDizzy wrote:I would e-mail TRE and see what they say.

I was just about to order one of these, hopefully they aren't just sending out Walbros now...
I called them today. Great customer service, but they said they ran out of their in-house TRE pump so they're currently giving these out to fill the orders. They will have their TRE pumps back in stock in the next week or two.

I'm on the fence because even running this pump dry for a few seconds, it's not exactly quiet.
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Re: In-tank Fuel Pump Modification

Post by cek »

Dake wrote:
SlickDizzy wrote:I would e-mail TRE and see what they say.

I was just about to order one of these, hopefully they aren't just sending out Walbros now...
I called them today. Great customer service, but they said they ran out of their in-house TRE pump so they're currently giving these out to fill the orders. They will have their TRE pumps back in stock in the next week or two.

I'm on the fence because even running this pump dry for a few seconds, it's not exactly quiet.
Did you tell them that the experts on the Internet (me) think walbro pumps suck because they are noisy and the pump they WERE selling was da bomb?
Dake
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Re: In-tank Fuel Pump Modification

Post by Dake »

cek wrote:
Dake wrote:
SlickDizzy wrote:I would e-mail TRE and see what they say.

I was just about to order one of these, hopefully they aren't just sending out Walbros now...
I called them today. Great customer service, but they said they ran out of their in-house TRE pump so they're currently giving these out to fill the orders. They will have their TRE pumps back in stock in the next week or two.

I'm on the fence because even running this pump dry for a few seconds, it's not exactly quiet.
Did you tell them that the experts on the Internet (me) think walbro pumps suck because they are noisy and the pump they WERE selling was da bomb?
I sure did.. left out your name though :D

The owner said they'll be back in stock in about 2 weeks. He suggested I use this one instead, which is in stock, the TRE 343:

https://treperformance.com/i-873-chevy- ... -1998.html

He said the only difference is the location and size of the bottom inlet - same pump with the same flow rate as the 340. Since it would take 2 weeks + shipping to get the 340, I'm going to give the 343 a try. I'll report back.

Customer service-wise TRE is great. They shipped my 343 out today (Friday) for free while I ship the 340 back.

try to
try to
Ju@n
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Re: In-tank Fuel Pump Modification

Post by Ju@n »

[quote="Dake"][/quote]

I bought one on the 27 of december (day of the order) and got a TRE (luckily). Will be doing this mod next month.
Do I have to delete the original In-line pump? Mine is working correctly but wanted to install a new one anyway.

Thanks
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