Fuel starvation at half-tank
 

I searched the site, and see that the last discussion on this was in 2012, but nothing was resolved.

I get fuel starvation on the track at half a tank of gas, meaning I have to run out and get more gas at lunchtime. The solution appears to be installing a second fuel pump, as M3s do. Problem is, nobody seems to know what that second fuel pump should be. I'd like to just buy a kit (same as M3s) if I can, but my understanding is that the M3 kit doesn't work with our gas tank for some reason.

Has anybody solved this problem?

have a look at this

CLICK HERE

I suffer the same problem.
I top of gas between sessions.

Be interested if you come up with a DIY guide.

Thanks, 2101. I know of the M3 solution, but when I inquired about it, I was told that 318s have a different tank than M3s, and we need a different pump (shorter, I think), but nobody knew what pump to use. The opinion was that I could use the M3 kit if I specified the correct pump.

I was hoping somebody on the forum had actually made this mod and could tell me what to buy and where from.

2101: I sent a query to bimmerworld. Found the email link in that document you supplied. Let's see what they say.

Rich

I'm pretty sure I asked James @ BW about it.
There is such a small market for this.

Consider a separate fuel cell?

I need to do this too, I can't stand having to fill up at the track when it gets close to 1/2.

If the M3s just use another M3 pump why don't we just use another ti pump?

I believe it has something to do with the shape of the tank.

i'm wondering if it wouldn't be cheaper to build/repurpose something into a surge tank with a walbro 255 in it. it may end up being less than oem pump housings and wiring connectors, etc. what do you guys think?

Just add a cheap in tank pump on the off side, doesn't have to be real high volume.
Cost 30 to 40 bucks.. It only has to run on track, so a switch can be added. Put a piece of AL tubing on the pump and have it pump into the factory pump baffle. I'd use fuel cell foam to hold it in place .. and it would not require much in the way of mods besides adding a power pass through to the guage flange..

^ great solution

Does the factory "housing" on the off side have provisions for a pump already? Or is that what the fuel cell foam is for?

Are you saying to have the aluminum tubing on the outlet of the pump cross over inside the tank? No extra lines on the outside of the tank? Very clean...

I read the pdf for the M3 fix, and they were running the pumps in parallel with a bunch of TEE fittings and I didn't like the sounds of that.

Yea I'd just make the pump so it pumps from the off side to the regular pump, In thinking about it, I'd probably just let it run if its a track car, with no load it would last forever. I haven't looked close inside my tank but would not be surprised if you could use the second fuel sensor opening and fab a fuel pump support to it just like the pump side, use a piece of strap to hold the pump and connect the pump to the factory one. The Walbro GM pumps are bullet proof.. Fuel cell foam would help stop fuel slosh as well.

Old thread but I finally addressed this issue last year.

I ended up converting to the pre '95 E36 fuel pump setup with external fuel crossover. The earlier pump and sender fit in the ti tank with no issues. The top of the tank had clips for the crossover tube as well.

I did have to trim the electrical connectors in a few spots so that they fit in the earlier receptacles but it was easy to do.

Fuel gauge works correctly and I'm able to go under a 1/4 tank on track without issues as opposed to starving at 1/2 tank before. I haven't had an opportunity to see how low it can get.

One thing is to not buy an eBay fuel pump like I did. I wasn't sure if the whole system would work so I went with a cheapy pump for testing, it worked on the road but the eBay pump failed pretty quickly once on track, lol.

Edit - Another reason not to buy eBay fuel pump, after the pump died I continued using the housing but with my old pump swapped in. Well that only lasted about 6 months, then the fuel level sender on the eBay housing quit working. New VDO unit works great.