Fuel pump installation

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de coupe

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The question that I do have is; Is there a fuel pump "internal" meaning in side the tank, that is from another model car "e12, e24, e28 ect." That would be a direct fit for the e9 tank. I do understand that alot of us are using external suckers or pumpers. One other question that I do have in routing your vapor return line for your fuel injection do you run it under the car or through the car"meaning through fire wall under seats ect" Also what size is this line most of the time 3/8, 1/2, 5/8, or 1/4. Thanks ever so much for the info Daniel
 
No internal fuel pump in the tank. The ones fitted to cars like the E28 5 series where more of a "booster" or feed pump for the main pump.
Originally the feed and return lines were under the car, but while I am rebuilding mine I am going to reroute them to the inside.

1/4 inch ID (8mm) feed and return is suitable.

HTH
Malc
 
Indeed, I'm just using the E28 external with a 1/8" return line tapping the upper part of the fuel tank. Works great so far.
 
I assume this is for the motronic conversion? Do you need one in the tank? You might be able to get away with out one but Carl's conversions uses one. The in tank pump in my old 535i went out and the only way you would know it is when you had less than 1/4 tank of gas it would give symptoms like it was running out of gas. I am using one in my motronic conversion and the pump to use can be sourced from a 325i; sorry I don't remember the year but I think it was a late 80s. The unit has both the pump and the fuel level sensor. I pulled one from a car at the junk yard. There were two different versions so you need to get the one with both the pump and fuel level sensor on the same unit. The fuel level sensor is not as long as the original, sits abut 3/4 inch higher off the bottom of the tank, so it will read empty a bit earlier.

Scott
 
As all ready stated, you can fit one if you like but the reality is that if you get the correct injection pump you don't need the intermal "lift" pump. I know from experience that if you use an early E24/E28 injection pump (there may be others) they are self bleeding (unlike some) so you can mount the pump above the fuel tank and it will still prime itself.
 
Early L-jet cars did not use an in tank pump, just the main high pressure pump. I ran my '75 e12 using only the high pressure pump after I converted to Motronic and had no problems at all.
 
welll....

I haven't asked Carl about it, and I run carbs, but I suggest the in-tank pump is slightly more "secure" being protected, and will run cooler being surrounded by gas.

In-tank will also run more quietly.

That said, the outside version will be cool as long as you don't run the tank empty; it will be safe if tucked up above the right rear half-shaft; and the electric pumps seem quiet enough to be un-noticed.

Unlike that damn loud mechanical/electrical Weber pupm thing I put in the 2002 when I used the head from a 318i. Now I know how Captain Hook felt about the croc - the pump was always tic-tic-tic back there. l learned something...
 
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