Fuel Tank / Pump upgrade

[jlevie]

If that is the approach you intend to use, then the return line wont be an issue.

[Jean]

Do you see anything wrong with it? I appreciate your input, I am just thinking out loud :)

[Conrad311]

This is something ive been thinking about doing too, but didnt really know how to go about it. Is it really as simple as replacing the in-tank pump with say a walbro 255, and patching in a line where the old external pump was? My ext. pump is just about shot, it makes a hell of a racket and i want to replace it with an intank high pressure pump, as i plan to turbo in the future, and run an adjustable fpr. so i can meet the fuel needs. Have any of you done this yet?

[Jean]

I can't find a thread, but someone on m42 forum did replace the intank pump with aftermarket pump.

Another issue with installing a LATE model tank with 2 fuel level senders is that the early car DOES NOT have an opening for the 2nd sender under the rear seat. So, one would have to be cut out OR the 2nd opening on the tank welded shut....

[Jean]

I am going to give this a shot in a few days. I have a late model pump removed from a late model fuel pump assembly, and I'll see if it will fit in the early style fuel pump assembly...

[Conrad311]

very cool man, let us know how it works out. So will you just be deleting the external pump if the new style pump works? My external pump is damn near junk so im looking for another option than paying 200 for another external when the transfer pump is propably on its way out too

[Jean]

Not going to work easy.... the early and late model pumps in their respective housings are different in size and how they mount.

My next option is to modify the late model pump housing by adding a return line to it....

[Jean]

I got some good news. I found out that the late model 318is pump has a built in return line (like the early 318 pump housing), unlike the 325i pumps that i've seen w/o one.
The only modification needed is the electrical connector is a different style, so grab the pig tail from the donor car..

Pics later today.

[Jean]

Here we go, a late model 318is pump/housing with the return line!






And to compare it with a late model 325i pump





And how the early 318i pump looks

[Jean]

If you replace the in-tank transfer pump with a high pressure pump you could eliminate the external high pressure pump. In the process you'll have to provide a fitting for the return line from the engine bay. The two pump system has the return in the flange of the low pressure pump and the later single pump system has the return going into the left side of the tank.

To clarify on this. I found out today that the 318is has one pump, and it's got a return line on it like the early pump on my car.

[Jean]

And a thread on replacing the pump in the 318is housing with tre340

http://www.treperformance.com/FuelPumps/TRE255FuelPumps.html#340

http://www.m42club.com/forums/showthread.php?t=9856

I think this is enough to drop the external pump ;)

[Mike]

interesting approach, I am taking notes....

[Benji_E30]

And a thread on replacing the pump in the 318is housing with tre340

http://www.treperformance.com/FuelPumps/TRE255FuelPumps.html#340

http://www.m42club.com/forums/showthread.php?t=9856

I think this is enough to drop the external pump ;)

have you droped the external pump yet? I've been thinking about the same thing but don't have the funds to try it as of right now...

[flawdaboi407]

nice! going to do this asap