In-tank Fuel Pump Modification

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

Post by ElGuappo »

Yes - you remove the original in line, high pressure pump when you install a new high pressure in tank pump.
Ju@n
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Re: In-tank Fuel Pump Modification

Post by Ju@n »

ElGuappo wrote:Yes - you remove the original in line, high pressure pump when you install a new high pressure in tank pump.
Thanks!
delorean175
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Re: In-tank Fuel Pump Modification

Post by delorean175 »

Thank you guys for the write up and info. I did this conversion last week and am very very pleased. The pump isn't audible from inside the car at all! :D My old pump was pretty loud. This new pump makes a subtle high pitch sound which can be heard standing next to the fuel tank.

cek: I used your method and it worked really well. kudos on saving and reusing the old little rubber piece as a step up to the 13mm hose. I made my fuel hose step down from 13mm to 8mm out of brass. My brazing skills aren't so hot, but I got the job done. :laugh: I wanted to ensure this would never leak.

Image

Image
ElGuappo
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Re: In-tank Fuel Pump Modification

Post by ElGuappo »

delorean175 wrote: cek: I used your method and it worked really well. kudos on saving and reusing the old little rubber piece as a step up to the 13mm hose.
Heretofore known as the 'Ceksy method' (said in Zap Brannigans voice - preferably while wearing a velour tunic)
delorean175
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Re: In-tank Fuel Pump Modification

Post by delorean175 »

ElGuappo wrote:Heretofore known as the 'Ceksy method' (said in Zap Brannigans voice - preferably while wearing a velour tunic)
That's a very specific, I like how you think. :laugh: I would have chosen Ron Burgundy in his fancy Burgundy colored suit. lol
SlickDizzy
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Re: In-tank Fuel Pump Modification

Post by SlickDizzy »

Note: if you do this mod on a Euro car with the twist-lock fuel pump, you must forego the foam rubber sleeve for the TRE pump. After carefully getting it onto my assembled fuel pump, I then found that it is too large to fit through the tank hole and had to cut it off...everything else just BARELY fits with some careful maneuvering but the sleeve just won't make it. :?
EuroShark
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Re: In-tank Fuel Pump Modification

Post by EuroShark »

Has anybody tried the Denso 1020 "Supra" pump? It looks fatter than the TRE but I can't seem to find dimensions. Worst case, as long as it fits through the tank opening I suppose the return line tube could be shortened or moved a bit. I've got one of the TRE pumps but with the mixed reviews all over the interweb I'm looking for something that might be a step up in reliability.
delorean175
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Re: In-tank Fuel Pump Modification

Post by delorean175 »

EuroShark wrote:Has anybody tried the Denso 1020 "Supra" pump? It looks fatter than the TRE but I can't seem to find dimensions. Worst case, as long as it fits through the tank opening I suppose the return line tube could be shortened or moved a bit. I've got one of the TRE pumps but with the mixed reviews all over the interweb I'm looking for something that might be a step up in reliability.
I would say, the only way to know is to try it out. I would think the Supra pump is a crap shoot in terms of tiffing through that hole. If its just slightly fatter than the TRE it could still work but without a rubber boot around it. I would prefer a pump with that rubber boot for noise dampening purposes. But its all up to preference. I'm very pleased with the TRE i have. It barely fits through that hole though. What kind of bad things have you heard about the TRE?
BimmerDan
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Re: In-tank Fuel Pump Modification

Post by BimmerDan »

I ran an Aeromotive Chevy pump, it was hard to fit but will fit with some wiggling.
https://www.aeromotiveinc.com/product/340-fuel-pump-gm/
EuroShark
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Re: In-tank Fuel Pump Modification

Post by EuroShark »

delorean175 wrote:I would say, the only way to know is to try it out. I would think the Supra pump is a crap shoot in terms of tiffing through that hole. If its just slightly fatter than the TRE it could still work but without a rubber boot around it. I would prefer a pump with that rubber boot for noise dampening purposes. But its all up to preference. I'm very pleased with the TRE i have. It barely fits through that hole though. What kind of bad things have you heard about the TRE?
I haven't heard anything more specific than reports of them dying after a year or two and leaving people stranded. Obviously this is possible with any pump and the longevity will depend on a number of factors. I'm starting with a tank that has been boiled out by a radiator shop so hopefully it's as clean as it can get. I did some digging and the Denso 1020 looks to be 50mm diameter and the outlet looks to be dead center rather than offset, so modification to the return tube may be necessary. I need to make sure the level sender will also fit correctly without the pump being in the way. If it can be done cleanly I'll grab one of these pumps and make it happen.
EuroShark
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Re: In-tank Fuel Pump Modification

Post by EuroShark »

Looks like the tank opening measures 52mm so the Denso 1020 isn't going to work without chopping something up.
delorean175
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Re: In-tank Fuel Pump Modification

Post by delorean175 »

That's a bummer, If you do figure something out, please post your results here. I think this thread could qualify to be a sticky. So the more info we post here the better it will be for future readers. Best of luck!
buzby
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Re: In-tank Fuel Pump Modification

Post by buzby »

https://www.amazon.com/gp/product/B0019 ... UTF8&psc=1

Just FYI I have run this pump in the M5 for over 6 months now and nearly 3000 trouble free miles. Works like a dream, relized in tank pump had failed when external pump got louder. Easy to fit. I did not want to mess with fitting a single pump or any other modifications at the time the in tank one failed.

Dave
Beemernut
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Re: In-tank Fuel Pump Modification

Post by Beemernut »

Just to clear up another point of failure for my upcoming road trip (I was too lazy to test if the old pump was actually bad :roll: ), I used a Carter P60293 which can be bought online or from your local parts store for $30-40 via the suggestion of someone else on here. It needed almost zero modification to work. The only issues were that the pump just kind of hangs there with nothing to secure it to the side of the return line (can be fixed with a zip tie), and the little rubber boot that stretches between the pump inlet and the return line had to stretch a bit farther than intended. Aside from that, the new pump is exactly the same length as the old one! Talk about bang for the buck :rofl:
Ju@n
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Re: In-tank Fuel Pump Modification

Post by Ju@n »

Hi!
Did this conversion today, didn't get to test it a whole lot though.
And I still didn't remove the inline pump, but the car starts and idles smoothly :)
I know it's not the best craftmanship ever, but I had a couple of problems.
Image
Image

First of all, when removing the assembly I must have broken the existing fuel pump, since it came up only because it was connected via the wires, the small nipple that comes out of the pump was broken.
Second, it seems somebody had already replaced the in-tank pump, since the unit was a delphi (and not similar to the OEM one).
So I had my work cut out, since I didn't have the small rubber hose connnection that cek used in his tutorial. I had to get creative, so in the end I used the small hose that comes with the TRE kit to step down the 12mm ID line to 8mm.
Another problem I had was that there was no metric line available when I went to buy some (incredible since I live in a "metric" country). So 1/2" and 3/8" had to do.
After testing a couple of lengths of the small 8mm line that came with the kit, to be sure that the pump wasn't hanging nor pressing on the bottom of the tank, I soldered up the wires and put a couple of zip ties (The pump that came out had been zip tied in place and the zip ties were not melt nor affected in any way, so I think that zip ties are actually not a bad way of doing this).
As cek said, extra care must be taken while inserting the pump back in the tank not to rip the rubber condom thingy the TRE pump has.
tn535i
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Re: In-tank Fuel Pump Modification

Post by tn535i »

The problem you will have above is that once you remove the main pump under the car, which you should, you will have to step the fuel line back down to 5/16" for the filter which you should keep in it's original place. I would also make sure that the roughly 1/2 line out of the old unit is good condition high pressure fuel line as the original was only intended for the low pressure side.

On our old e30 there was this little accumulator thing that changed the line from 1/2 to 5/16 and maybe had a right angle. It made doing it this way easy but did swap out the old 1/2" (13mm) hose with NEW high pressure fuel injection hose.
Ju@n
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Re: In-tank Fuel Pump Modification

Post by Ju@n »

tn535i wrote:The problem you will have above is that once you remove the main pump under the car, which you should, you will have to step the fuel line back down to 5/16" for the filter which you should keep in it's original place. I would also make sure that the roughly 1/2 line out of the old unit is good condition high pressure fuel line as the original was only intended for the low pressure side.

On our old e30 there was this little accumulator thing that changed the line from 1/2 to 5/16 and maybe had a right angle. It made doing it this way easy but did swap out the old 1/2" (13mm) hose with NEW high pressure fuel injection hose.
Yes! I didn't post on that particular part, because I still haven't done it, I bought an barbed adapter, from 12mm to 8mm, I hope it will make my life easier when removing the old pump!
Similar to this one -> Image
I'm hoping it will withstand fuel and pressure...
davintosh
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Re: In-tank Fuel Pump Modification

Post by davintosh »

Ju@n wrote:
tn535i wrote:The problem you will have above is that once you remove the main pump under the car, which you should, you will have to step the fuel line back down to 5/16" for the filter which you should keep in it's original place. I would also make sure that the roughly 1/2 line out of the old unit is good condition high pressure fuel line as the original was only intended for the low pressure side.

On our old e30 there was this little accumulator thing that changed the line from 1/2 to 5/16 and maybe had a right angle. It made doing it this way easy but did swap out the old 1/2" (13mm) hose with NEW high pressure fuel injection hose.
Yes! I didn't post on that particular part, because I still haven't done it, I bought an barbed adapter, from 12mm to 8mm, I hope it will make my life easier when removing the old pump!
Similar to this one -> Image
I'm hoping it will withstand fuel and pressure...
Most all of the concerns about adapting different hose diameters and high pressure can be solved by using the original return line for the supply line. That's what I did on the assembly I modified for my old 528e (roll back to page 3 of this thread) for more info. You could use that barbed adapter on your return line, and not worry so much about the pressure. I picked up a similar brass adapter from a home improvement store; to get it to fit inside the return pipe on the pump assembly, I chucked it up in a drill and spun it on a file and sandpaper until it fit, then used a fuel-rated epoxy to attach it and seal it up.

Image
image by davintosh, on Flickr

The beauty of it is that you eliminate the larger diameter hose from the fuel system entirely. All you do is cut off the return line pipe so that the pump can fit in. I added a return pipe extension mostly to support the pump, but in retrospect it's probably unnecessary because the clamps and the bit of hose should be able to keep the pump in place with no problem, and deleting it would make fitting the assembly back into the tank a lot easier.
Ju@n
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Re: In-tank Fuel Pump Modification

Post by Ju@n »

[quote="davintosh"][/quote]

Apart from making that barbed fitting fit inside the 12mm inlet, you also "enlarged" the line to the bottom of the tank, right?
tn535i
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Re: In-tank Fuel Pump Modification

Post by tn535i »

Another nice solution is to buy an external check valve with 1/4 FNPT and fit it with two different hose barbs to step down the size. I have one like this...

https://www.mcmaster.com/#catalog/124/527/=1cda1g0

7768K52

This is what I had planned to do for my 6 which I think has a dead in-tank pump and the check valve in the main pump seems to leak down. I'm debating exactly what to do on that car but bought this an a way to accomplish it. It starts quickly most fo the time and runs great if I don't let the fuel level drop too low.
Last edited by tn535i on Apr 11, 2018 1:36 PM, edited 1 time in total.
davintosh
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Re: In-tank Fuel Pump Modification

Post by davintosh »

Ju@n wrote:
davintosh wrote:
Apart from making that barbed fitting fit inside the 12mm inlet, you also "enlarged" the line to the bottom of the tank, right?
Lengthened it, yes, but as I mentioned above, that’s probably unnecessary. Lots of other cars use high pressure pumps that are supported only by the stub of hose on the assembly. If I were to do it again, I’d go this route.
Ju@n
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Re: In-tank Fuel Pump Modification

Post by Ju@n »

Hi guys,
Just wanted to let you know I ended up re-doing this, since the small rubber 8mm hose stretched a bit when in contact with gas and failed.
What I ended up doing was cutting less than 1/2" from the hanger pipe and using more 8mm hose. That way the hose clamp would grab more firmly the hose within the hose :laugh:
Bigdoug92
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Re: In-tank Fuel Pump Modification

Post by Bigdoug92 »

I did this mod a few weeks ago when my intank pump went bad and now it takes my car about 10 seconds to start and the hotter it gets the worse it runs, basically falls on its face and wont go after about 1/2 throttle. I orginally thought it was a vacuum leak because i noticed i had a small tear in a vacuum line and the rubber intake boot had seen better days. After replacing both i am still having the same issue and now thinking its fuel related. Could it of been something i did wrong? Wrong pump, filter in backwards, ect?
demetk
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Re: In-tank Fuel Pump Modification

Post by demetk »

I put a Walbro pump in my car and it starts within 1 sec of cranking. You will need to get back in there and check it out. Post pics.
Ju@n
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Re: In-tank Fuel Pump Modification

Post by Ju@n »

demetk wrote:I put a Walbro pump in my car and it starts within 1 sec of cranking. You will need to get back in there and check it out. Post pics.
+1!
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