M42 -> M30 Fuel Line Question

[wildstoats]

Hey guys. I'm getting ready to hook up my fuel lines and I realized that the m42 looks like it had 2 fuel feed lines. I was going to just "Y" these together and run the output from that into my m30 fuel rail. Is there any reason this wouldn't work? Does anyone even know if the 318i (m42) pump will even work with the m30?

M42 rail for reference:

[Jean]

Isn't 12 IN and 13 OUT? Just looking at the diagram if the thing connected to 16 is fuel filter.

[mattdk318i]

oops, NVRMND

[wildstoats]

Isn't 12 IN and 13 OUT? Just looking at the diagram if the thing connected to 16 is fuel filter.

Well I was wondering why I had 3 lines coming up together that looked like fuel lines. But in a moment of clarity I just realized that one of those is probably for the charcoal canister. The car was kind of gutted when I got it and I'm really not familiar with m42's at all. I'm assuming the late 318i still had a charcoal canister?

[Erick]

Jean,

11 is OUT. Fuel Pressure Regulator is the dead giveaway. I say why not test it? Put a bottle on each end of the hose and turn the pump on. See where fuel comes from and voila! You'll know if you need to tie them together, or just ignore one.

As for the M42 pump working with the M30, I'm 95% sure you're fine. The e30's fuel setup is chassis/year based, not model based. They used the same internal/external pump setup on all e30s up to 09/87 (might be a bit off on the date), and all e30s beyond that got the same internal only pump setup.

- Erick

[Jean]

Erick - sorry I didn't mean to give wrong info. I thought that the line from the FPR was a vacuum line... I should have just kept quite as I've never touched an m4x engine before :)

[Erick]

Wait, good point. I was just looking for the FPR because as far as I know, I have yet to see an older car (or any car) with the return NOT on the FPR.

That diagram only shows one hose, so either it's not including the vacuum hose, or you would be correct.

Crazy M42s.....

[wildstoats]

Yeah the diagrams really weren't making sense to me either. I traced the lines back but I couldn't quite tell what was going on. I was just asking in case anyone knew right off the top of their heads.

Edit: I also just double checked that diagram and REALOEM has #11 is listed as a vacuum line for what it's worth, with #12 being the inlet and #13 being the outlet. So that clears that up.