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M6 stalling out, some loosing power at low RPM

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hornhospital
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Re: M6 stalling out, some bucking at low RPM

Post by hornhospital » Thu Jul 27, 2017 1:43 am

I just realized that we've completely hijacked sixracer's thread. Sorry about that. So this will be my last posting in this thread about the too-bright LED and Light Dims. Picture attached (I will trim it and smooth it better later). I like it. Bright enough to see in daylight, but well dimmed at night so as to be much less distracting.
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Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'87 325is "Odette"; '93 325is "Elvira"; '95 M3 "Ashlyn"

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dwcains
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Re: M6 stalling out, some bucking at low RPM

Post by dwcains » Wed Aug 09, 2017 9:28 pm

Got the orange LED voltmeter today. Looks really nice, but I don'[have it hardwired, yet. Just tried the red (+) and black (-), and the display just shows 00.0, but there is also a green and I didn't want to experiment with. Contacted seller, and pics to follow.
Dean
Lutz, FL

'85 635 CSi Euro #9402254
'87 Spider Veloce
'92 Spider Veloce
'08 350Z

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Sixracer1
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Re: M6 stalling out, some bucking at low RPM

Post by Sixracer1 » Sun Apr 22, 2018 2:46 am

I replaced the main and fuel pump relays and the car doesn’t seem to be having any more issues.
'85 M635CSi #64
'01 325XiT
(Formerly "Sixracer")

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Sixracer1
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Re: M6 stalling out, some bucking at low RPM

Post by Sixracer1 » Wed May 02, 2018 8:26 pm

Took the car for a test drive today to make sure the relays solved the issue. Car has been sitting for the winter so this was first drive for a while.

On start, car was idling rough, eventually settled down. Drove for 15-20 mins for things to get up to temp. After some hard acceleration the bucking/stalling started again. I parked for 5 mins then got the car going again smoothly by holding it at 3000rpm for a few secs. Drove back to garage no problem, running normally.

I am starting to shop for fuel pumps. Man those things are pricey!

Any other suggestions from the crew here?
'85 M635CSi #64
'01 325XiT
(Formerly "Sixracer")

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tschultz
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Re: M6 stalling out, some bucking at low RPM

Post by tschultz » Fri May 04, 2018 3:48 pm

I would go with Walbro external high capacity fuel pump for about $80 plus a couple fittings to make it work. Don't worry about the in tank pump at all.


From my notes:

You need the following for a comprehensive replacement:

1 - Walbro 255lph inline fuel pump (I used Walbro GSL392)
1 - 8mm barb - 10mm x 1.0mm male (Walbro P/N 128-3024)
1 - 12mm barb - 10mm x 1.0mm male (Walbro P/N 128-3025)
1 - Few meters of 8mm x 13mm fuel house (BMW P/N 13311722262), 5/16" works fine.
1 - Meter of 12mm x 18mm fuel hose (BMW P/N 16121176440)
7/16" will work IF you can locate high pressure EFI line.
1 - New hose clamps, ABA or style that does not cut into hose

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Sixracer1
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Re: M6 stalling out, some loosing power at low RPM

Post by Sixracer1 » Mon Jun 04, 2018 4:07 pm

I ended up sourcing an in-tank fuel pump from Europe and after a few weeks of waiting it is in and car is running great now.
I am going to replace the inline pump now as a precaution given it was likely tortured a bit with the in-tank dead.

I guess when I held the car at about 3000 RPM the inline pump was able to siphon enough gas from the tank. Any higher RPM and the pump would go dry as it couldn't pull enough and I would lose power. Then when I got off the throttle the inline pump wouldn't be pulling hard enough to restart the siphon.
'85 M635CSi #64
'01 325XiT
(Formerly "Sixracer")

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