Parts Catalog Accessories Catalog Tech Info Tech Forums
 
  Search our site:    
 Cart  | Project List | Order Status | Help    



Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > 911 / 930 Turbo & Super Charging Forum

Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
930turbo's Avatar
 
Join Date: Jul 2006
Location: Valrico Florida
Posts: 199
Fuel pump(s) question

Should the engine be able to run with either one of the pump relays removed? My car will run (at least idle, I didn't try driving it) on the front pump by itself but will not run on just the rear pump. Is this right or do I have a failed rear pump?
Old 12-02-2006, 09:29 AM
  Pelican Parts Technical Article Directory    Reply With Quote #1 (permalink)
Registered User
 
930turbo's Avatar
 
Join Date: Jul 2006
Location: Valrico Florida
Posts: 199
I disconnected the rear pump and drove the car today. It seemed to be a little richer (??) across the range and the same available power @ full throttle. OK, I'm confused.
__________________
'77 930 turbo Garretson I/C 1 BAR spring, (2) '82 Triumph Bonneville Royal Wedding Edition
Past rides: '74 914 1.9 liter twin plugged track car, '83 928S, '87 924S, '75 911S w '78 ROW 3.0, '72 911T, '70 911T and various other insignificant domestic examples. Happiness is a grey tailpipe! Turbo lag......it's worth the wait!
Old 12-03-2006, 06:14 PM
  Pelican Parts Technical Article Directory    Reply With Quote #2 (permalink)
Registered User
 
WydRyd's Avatar
 
Join Date: Mar 2002
Posts: 3,563
Careful running just the one pump.. you *might* not be getting the appropriate fuel pressure at high loads with the one single pump, which could cause problems

They are both in series, right?

I know mine are, but mine's an aftermarket turbo setup that relies on such high pressures, which one pump would not be able to meet the demands.
__________________
Merv
'89 911 Turbo Cab
Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition
Old 12-03-2006, 06:22 PM
  Pelican Parts Technical Article Directory    Reply With Quote #3 (permalink)
Registered User
 
930turbo's Avatar
 
Join Date: Jul 2006
Location: Valrico Florida
Posts: 199
The richer mixture was due to lack of voltage to the WUR, which is tapped off the rear pump circuit. Any fellow 930 owner, I need your help. I need to know if your car will run on either one of the two pumps. It's easy to check, just pull the red relays out one-at-a-time and see if it still runs. Please let me know.
__________________
'77 930 turbo Garretson I/C 1 BAR spring, (2) '82 Triumph Bonneville Royal Wedding Edition
Past rides: '74 914 1.9 liter twin plugged track car, '83 928S, '87 924S, '75 911S w '78 ROW 3.0, '72 911T, '70 911T and various other insignificant domestic examples. Happiness is a grey tailpipe! Turbo lag......it's worth the wait!
Old 01-07-2007, 07:30 PM
  Pelican Parts Technical Article Directory    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Apr 2002
Location: Concord, NC
Posts: 810
the car will run on the front fuel pump, but it will affect pressure, and above 4000 RPM will lean it out too much.

Brian
__________________
Brian Keith Smith
Competition Custom Paint
1983 930
My Track Videos
TEC3 EFI Conversion on 1983 930
Old 01-08-2007, 05:37 AM
  Pelican Parts Technical Article Directory    Reply With Quote #5 (permalink)
Registered User
 
Join Date: Aug 2004
Location: enfield ct
Posts: 498
Garage
How do the pumps work in tandem ? I just replaced my front pump but I believe the rear pump is not working correctly . The front pump seems so much stronger then the rear at least by noise . Can some one explain ? I seem to be leaning out at high boost.
__________________
1986 blk 930
2000 expedition
2000 bmw 3 series convertable
1996 Silverton 312 sedan bridge
Old 01-08-2007, 02:22 PM
  Pelican Parts Technical Article Directory    Reply With Quote #6 (permalink)
 
Now Available for Ordering:   101 Projects For Your BMW 3 Series 1982-2000  [more info]
Registered User
 
WydRyd's Avatar
 
Join Date: Mar 2002
Posts: 3,563
One pump will not meet the required fuel pressures required by the engine under full boost. Ensure both pumps are working before driving under heavy load.

FYI, I run two BOSCH 044 700HP fuel pumps in series to meet the fuel pressure demands of my setup
__________________
Merv
'89 911 Turbo Cab
Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition

Last edited by WydRyd; 01-08-2007 at 03:01 PM..
Old 01-08-2007, 02:42 PM
  Pelican Parts Technical Article Directory    Reply With Quote #7 (permalink)
Registered User
 
930turbo's Avatar
 
Join Date: Jul 2006
Location: Valrico Florida
Posts: 199
Steven, your experiencing the same situation I am. My front pump sounds powerful and the car will run on just that pump. The rear pump is nearly inaudible and the car stalls as soon as you disconnect the front pump indicating it does not have the delivery capacity to support even running at an idle. I thought if soemone out here could disconnect their front pump breifly while their car was idling, we could confirm if this is normal operation. I'm not sure if a healthy rear pump would be capable of drawing fuel through a stalled front pump. My car has a 1.0 bar spring installed but I only get about .7 bar most of the time. Occasionaly, it does go to 1.0 and it's a great thrill but doesn't last long.
Old 01-10-2007, 09:23 AM
  Pelican Parts Technical Article Directory    Reply With Quote #8 (permalink)
Registered User
 
930turbo's Avatar
 
Join Date: Jul 2006
Location: Valrico Florida
Posts: 199
I disassembled the rear pump today and discovered the problem. The armature was turning but the pump was not. This explains why it was so quiet, it wasn't doing anything but humming. The armature shaft was frozen in the bearing and the armature winding broke loose and was rotating on the stationary shaft. That's probably too much information, but I just had to know. Time to buy more parts - again. I'm sure the wife will understand.
__________________
'77 930 turbo Garretson I/C 1 BAR spring, (2) '82 Triumph Bonneville Royal Wedding Edition
Past rides: '74 914 1.9 liter twin plugged track car, '83 928S, '87 924S, '75 911S w '78 ROW 3.0, '72 911T, '70 911T and various other insignificant domestic examples. Happiness is a grey tailpipe! Turbo lag......it's worth the wait!
Old 02-12-2007, 03:57 PM
  Pelican Parts Technical Article Directory    Reply With Quote #9 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 12,690
Garage
Sorry I did not see this thread sooner, I could have told you that a 930 will run in "limp mode" on the rear pump alone.
A buddy of mine hit a 18 wheeler's retread on the way to the track once and it took out the front pump. He was able to get it home using the rear pump alone and no boost.
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 02-12-2007, 04:45 PM
  Pelican Parts Technical Article Directory    Reply With Quote #10 (permalink)
Registered User
 
930turbo's Avatar
 
Join Date: Jul 2006
Location: Valrico Florida
Posts: 199
My situation was the opposite. My rear pump failed. I could get up to .7 boost before it either leveled off of bucked horribly. I have a 1.0 bar spring in the WG. It went there once upon a time. My pump is in the mail, I'm waiting on the front porch for it to arrive :-).
__________________
'77 930 turbo Garretson I/C 1 BAR spring, (2) '82 Triumph Bonneville Royal Wedding Edition
Past rides: '74 914 1.9 liter twin plugged track car, '83 928S, '87 924S, '75 911S w '78 ROW 3.0, '72 911T, '70 911T and various other insignificant domestic examples. Happiness is a grey tailpipe! Turbo lag......it's worth the wait!
Old 02-12-2007, 04:54 PM
  Pelican Parts Technical Article Directory    Reply With Quote #11 (permalink)
Registered User
 
ELZ's930's Avatar
 
Join Date: Jan 2004
Location: "The Natural State"
Posts: 779
Keep us posted on the results....good luck!
__________________
the911den.com

Instagram / UberPorsche930
Old 02-14-2007, 10:25 AM
  Pelican Parts Technical Article Directory    Reply With Quote #12 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 07:20 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2016 Pelican Parts - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.