It is snuggled right up to the intake on the cold side of the plastic shield that goes between the engine and the frame rail to separate the cold air intake (not installed). Coming in hot after a race the tank is cool to the touch. It is pumping 60Gal per hour at low pressure between the main tank and the swirl pot so it really isn't there long enough for heat soak to bother it much anyway. The only high pressure flow is right there - pot to tank to pot again.
#54 GTS-3/CM E30 Race car
90 Porsche 964 C2 Daily driver
05 BMW 325XiT Kid hauler
04 Chevy 2500HD Duramax
Perpetual hopeless, unfinished projects
^Thanks. Good to know. I wasn't sure how the fuel was being routed and thought that maybe it was sitting in the swirl pot just before the fuel rail.
Do you have a routing schematic of the fuel system setup? I'd love to see it.
Looks like the fuel is always cycling through the swirl pot and doesn't sit there for long. Thanks for taking the time to explain this out.
Should be fine - it would still have been submerged, so shouldn't overheat.
Cliff
I fixed the wiring yesterday. I jumpered the relay and disconnected the primary pump, and I can clearly hear fuel dumping into the passenger side of the tank. Now, I just need to give it a proper track test....
I also need to have a word with the guy I paid to install the kit, although if BW had color coded the supplied wiring harness it might have prevented the mixup. Human Factors engineering, and all that stuff.
'95 M3 S54 Track Toy
'19 X5 40i M-Sport
'16 Cayman GT4
‘23 GR Corolla
Found this older thread that applies to me as well. during a recent dyno run we saw that the single stock pump (95 M3) is not getting enough fuel to the engine, even with the parameters bumped up.
One thought I had was could I add another new pump to make mine a dual system and not replace the existing one that is able to run fine to about 3500 rpm but not at WOT? Save me a few dollars and get me the dual type upgrade even though I have not experienced any full out starvation, although maybe I've been running lean due to the pump.
Consensus among racers is that 2 pumps in parallel do not work that well. Better is a 2nd pump feeding the accumulator of the main pump.
In my case I discovered the problem is actually an old weak fuel pump. Replacing it with a brand new BMW pump (not 2nd hand or aftermarket) solved the problem. I'm running a stock early E36 pump. With a 410hp S54 I have no problems feeding the engine. I have a 2nd similar pump filling the bucket for the first pump.
You could use your old pump to feed the main pump. It's not building pressure so it should have no trouble doing that job.
Have you tried other causes? Fuel filter? Pressure regulator?
Last edited by PCarroll; 01-23-2013 at 01:10 PM.
Peter Carroll - http://www.driversmeeting.com/pcarroll
BMW Club Instructor & Club Racer, 1997 BMW M3 GTR #321
2008, 2009, & 2011 BMW CCA National C-Mod Champion
Videos channels at:
http://vimeo.com/pcarroll/videos
http://www.youtube.com/user/pc270
The filter I changed out 6 months ago so I think I'm good there, We didn't look into the regulator. I asked the tech I was working with during the dyno session about checking the regulator of the pressure off the pump and he said in his experience it is almost always the pump?????
My thought was to check right at the pump to see what it was putting out.
an easy way to check the fuel pressure regulator is to pinch off the fuel line on the return after the regulator. If you get your fuel ratio back, then it is your regulator. We just used a pair of vise grips.
BMW e36 M3 #11 ST-3
OK, just did a test of the fuel pump and unless I did something wrong I'm seeing very high pressure. I put the test gauge directly onto the pump, not setup using a tee and in that mode I get about 80psi.
But is that a different type reading than if I setup with a tee since it isn't a close loop and the fuel can flow? Thinking I need to set this up differently.
Today
Hope I can get a little help on what I've found.
I installed a tee at the fuel pump to do the test the proper way.
- test was just jumping the relay and I got 47psi
- test was with the relay in running the car, doing this I got 41psi
- tested rev the engine and I do see the need sweep up, maybe to about 43-44psi
My Bentley manual specifies a pressure of 43.5 for this S50 engine, but I have one reading over and one under not sure how this relates? This whole exercise stems from during a tuning session we could not get the fuel at high RPM to a level about 14.7:1 to a desired level of about 13:1 or so. The tech told me with his experience it would be the fuel pump, but thee numbers don't look too far off?
Last edited by MCMM3; 01-30-2013 at 07:41 PM. Reason: Automerged Doublepost
I have a question for those who have installed the second fuel pump and use it as a transfer pump set up.
In post 1995 e36's, like in my 1996 328, there is a siphon pump that connects to the base of the sending unit and is powered by the fuel return to transfer fuel from driver's side to passenger side tank. My question is; when you install the second fuel pump to act as a transfer pump, do you just ignore the original siphon system (can be seen sticking out in the picture below) and let it sit in the tank unused or is it somehow reused by the transfer pump?
- 96 328is 6.0L. (LS1 to LS2 build thread: http://forums.bimmerforums.com/forum...ad.php?2098938)
- 96 328is 5.7L. (LS1 build thread: http://forums.bimmerforums.com/forum....php?t=1289987)
- 95 ///M3 6.0L. (LS2 build thread: http://forums.bimmerforums.com/forum....php?t=1619249)
- 97 ///M3. (e46 Fender Flares/track car build thread: http://forums.bimmerforums.com/forum....php?t=1727098)
- 96 328is (Dual Fuel Pump to Surge Tank thread: http://www.bimmerforums.com/forum/sh...ad.php?1964025)
I too have a question. I have a 2nd transfer pump in my 93 325is, as I started having starvation issues with my car after I changed the original primary pump. Is there a "correct" orientation for the pickup sock/filter? Should it point to the rear, driver's side, etc...? When my tank gets down to about 1/8, the transfer pump starts getting cranky and sucks air pretty often. I also experience starvation going in a straight line with the replacement primary pump when the fuel gets really low, whereas I used to be able to autocross on fumes with the original OEM pump.
If I recall correctly... You need to use two pre-95 pumps as the later pump does not have a connection for the return line. It went to the other left level sender. i.e. with two late pumps, you have two senders and no returns. I also recall you rotate the 2nd pump 90-deg so the pickup is more towards the outside of the tank. You lose the siphon assembly completely.
Interestingly, the E46 M3 does not suffer as bad from starvation and it uses a similar jet pump (venturi siphon thingie) pickup on the other side. I wonder if swapping the jet nozzle from an E46 would make a difference? Or maybe it's just a higher flow pump that makes a bigger jet?
Either way... 2 early pumps works great!
Peter Carroll - http://www.driversmeeting.com/pcarroll
BMW Club Instructor & Club Racer, 1997 BMW M3 GTR #321
2008, 2009, & 2011 BMW CCA National C-Mod Champion
Videos channels at:
http://vimeo.com/pcarroll/videos
http://www.youtube.com/user/pc270
Toward the outside of the car - or away from the center of the car. Where the fuel sloshes to in a corner...
Remember this DIY paper?
http://www.pumpkininc.com/content/doc/guide/ag-8.pdf
It's all in there... Except, you don't want them in parallel (as it recommends). You want the 2nd filling the accumulator. And you don't need all the extra wiring. Mine just run in parallel. Maybe up the fuse a bit. I think I'm running a 20A fuse. They don't draw that much...
Last edited by PCarroll; 02-03-2013 at 10:50 PM.
Peter Carroll - http://www.driversmeeting.com/pcarroll
BMW Club Instructor & Club Racer, 1997 BMW M3 GTR #321
2008, 2009, & 2011 BMW CCA National C-Mod Champion
Videos channels at:
http://vimeo.com/pcarroll/videos
http://www.youtube.com/user/pc270
I too have both my pumps wired in parallel to the OEM wiring. I also have my plumbing in series - return from engine into lhs pump, pressure feed from lhs pump to return of rhs pump, and pressure feed from rhs pump to engine. That page you linked used to say to orient the pump towards the back of the car. That's what I did. I'll need to open it up and revise my setup. Thanks for the feedback.
I could be wrong on that bit. I let someone else do my in-tank part...
Peter Carroll - http://www.driversmeeting.com/pcarroll
BMW Club Instructor & Club Racer, 1997 BMW M3 GTR #321
2008, 2009, & 2011 BMW CCA National C-Mod Champion
Videos channels at:
http://vimeo.com/pcarroll/videos
http://www.youtube.com/user/pc270
Just to update on the subject. I wrote a DIY to show how I did dual fuel pump setup as my set up for 96+ style pump is slightly different from the "typical" configuration...
Here is the link to the DIY: http://forums.bimmerforums.com/forum....php?t=1964025
- 96 328is 6.0L. (LS1 to LS2 build thread: http://forums.bimmerforums.com/forum...ad.php?2098938)
- 96 328is 5.7L. (LS1 build thread: http://forums.bimmerforums.com/forum....php?t=1289987)
- 95 ///M3 6.0L. (LS2 build thread: http://forums.bimmerforums.com/forum....php?t=1619249)
- 97 ///M3. (e46 Fender Flares/track car build thread: http://forums.bimmerforums.com/forum....php?t=1727098)
- 96 328is (Dual Fuel Pump to Surge Tank thread: http://www.bimmerforums.com/forum/sh...ad.php?1964025)
BW kit since 2011. No problems. Just drive on track until the reserve light comes on. No starvation.
Level8Drummer
Driving instructor for: BMWCCA, PCA, SCCA, Chin Motorsports, and Hooked on Driving.
I'm curious if anyone has had problems with this dual pump install and having electrical issue afterwards. I did the install per the BW instructions and at first all was OK. In this setup the electrical connection is spliced at the wire going to the passenger side pump and the new pigtail is added to connect the driver side pump.
My first time out at Rd Atlanta car ran great first session then it die in pit during driver change??? We thrashed around and found the fuel pump fuse was blown, we repalced it and got my wife out for her session. Then is was dead when I started for my session again, this time we were able to just pull out the relay wait 1-2 minutes and replace and it started, once started it would run fine on track??????
Fast forward to today, I ran the car around the neighborhood for 10 minutes all good, started the car after sitting for an hour to back out of the garage and shut it off, 10 minutes later tried to start it and it won't run again!!!! This time I can't get it running, I've got two relays one is brand new just installed yesterday and neither it or the old will work? If i jumper the socket I get the fuel pump going and the car will run. But can't get the relays to work!
So I can repalce another relay but I'm starting to think something is making the relays fail, has anyone had an issues like this? The fuel pump fuse is only a 15A fuse, I'm wondering if the fuel pump cirsuit is able to run doth pumps through this circuit. I'd had a recommendation to try a 20A fuse and that is what I had in today, but maybe this is tied to causing the relay failures?
Any help is appreciated, gotta get this ready for the track in 5 days!!!!!!
When replacing relays did you use BMW Fuel Pump relay or some other one? I know BMW has some relays that have different connections (ie pins are shifted around).
Also, although it might be good in 90-95% of the time, I would never double load the circuit. I ran separate relay, fuse and wires. I only used OEM pump wiring to trigger the new relay for the second pump. See my link in post 46 for my DIY set up.
- 96 328is 6.0L. (LS1 to LS2 build thread: http://forums.bimmerforums.com/forum...ad.php?2098938)
- 96 328is 5.7L. (LS1 build thread: http://forums.bimmerforums.com/forum....php?t=1289987)
- 95 ///M3 6.0L. (LS2 build thread: http://forums.bimmerforums.com/forum....php?t=1619249)
- 97 ///M3. (e46 Fender Flares/track car build thread: http://forums.bimmerforums.com/forum....php?t=1727098)
- 96 328is (Dual Fuel Pump to Surge Tank thread: http://www.bimmerforums.com/forum/sh...ad.php?1964025)
Well I'm pretty stumped.
First to answer the question I had first tried a Beck/Arnley replacment , then just tonight thinking both the original and the Beck/Arnley were shot I picked up a IDI brand relay at a local parts store. I installed the relay, turned on the switch, and tested the power at the fuse and saw nothing, so I assumed that I had no clue and the relay wasn't an issue. So I boxed up the IDI I just bought. Popped in the Beck/Arnley relay and tested and still got nothing at the fuse, confirmed the pins like you said and all was correct. Totally stumped I just reaching in and instead of just in the on position I cranked it and it started.
Now I'm confused, I thought I would see power at the fuse when the key was in the on position but is that my mistake it should be in start (cranking) to test?????
Still doesn't make sense why it just decides to not start some times?
Last edited by MCMM3; 04-06-2013 at 08:08 PM.
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