djet fuel pump problems... |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
djet fuel pump problems... |
biggy72 |
Nov 29 2008, 07:21 PM
Post
#1
|
Member Group: Members Posts: 209 Joined: 14-January 06 From: Olympia, WA Member No.: 5,418 Region Association: Pacific Northwest |
Do djet fuel pumps ever have the fuel pump portion go bad and not the motor portion? Mine is pumping more fuel out the return port than it is out the high pressure port. I pulled it apart and everything looks to be ok, but maybe it's just worn out. I have the pump out of the car and I was bench testing it so I'm sure it's not just incorrectly plumbed or wired.
I'd like to put a new pump under the gas tank, but I would need to run new fuel lines to take the pressure to do that and I was just hoping to get it up and running to make sure everything is working ok before I jumped into a project like that. |
SLITS |
Nov 30 2008, 09:27 AM
Post
#2
|
"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
Just go with the single in / single out pump used on the '75 - '76. Cheaper than the 3 port.
SS lines are not that hard to install with the engine out. 3/8" supply, 5/16" return. Your check valve in the 3 port pump could be weak / broken. Usually they will leak around the electrical connector. They can be rebuilt, but why? ANY pump that puts out 30+ PSI is potentially useable (I forget the liters/min output required ... your Haynes manual has that info). |
swl |
Dec 1 2008, 09:25 PM
Post
#3
|
Senior Member Group: Members Posts: 1,409 Joined: 7-August 05 From: Kingston,On,Canada Member No.: 4,550 Region Association: Canada |
I had the problem you describe and figured it is the rubber piece on the centerline side of the pop off valve. It sticks in the bypass mode instead of moving out when the fuel starts flowing. That valve, from what I have gathered, was intended to shunt air in the line to the return rather than pressurizing it to the fuel rails. The air doesn't have enough pressure to move out the pop off but fuel does. When the rubber tit gets sticky even the fuel doesn't have enough pressure to move the pop off out. I never found a solution. No rubber kits available - had to write off the pump.
|
jd74914 |
Dec 1 2008, 09:44 PM
Post
#4
|
Its alive Group: Members Posts: 4,782 Joined: 16-February 04 From: CT Member No.: 1,659 Region Association: North East States |
Do djet fuel pumps ever have the fuel pump portion go bad and not the motor portion? Mine is pumping more fuel out the return port than it is out the high pressure port. I pulled it apart and everything looks to be ok, but maybe it's just worn out. I have the pump out of the car and I was bench testing it so I'm sure it's not just incorrectly plumbed or wired. I'd like to put a new pump under the gas tank, but I would need to run new fuel lines to take the pressure to do that and I was just hoping to get it up and running to make sure everything is working ok before I jumped into a project like that. My pump had the same problem. IIRC I fixed it by swapping out the spring in the bypass valve "bump" (that is normal to the ports) with a stiffer one from another pump with a seized motor. |
Root_Werks |
Dec 1 2008, 09:53 PM
Post
#5
|
Village Idiot Group: Members Posts: 8,338 Joined: 25-May 04 From: About 5NM from Canada Member No.: 2,105 Region Association: Pacific Northwest |
I just went through this. Toss that 3 port pump out and get a 75-76' FI pump as stated. It simplifies the install and they are avail new still.
|
biggy72 |
Dec 1 2008, 10:27 PM
Post
#6
|
Member Group: Members Posts: 209 Joined: 14-January 06 From: Olympia, WA Member No.: 5,418 Region Association: Pacific Northwest |
In another post someone said something about buying prebent fuel lines for the tunnel. Where can you get them at, and if I were to make them myself what sort of flare should I use on the ends to make sure the high pressure rubber lines stay on?
|
biggy72 |
Dec 1 2008, 10:39 PM
Post
#7
|
Member Group: Members Posts: 209 Joined: 14-January 06 From: Olympia, WA Member No.: 5,418 Region Association: Pacific Northwest |
Also if anyone needs a simple good and cheap fuel pump a Ford fuel pump used from 86-91 works well. The part numbers it can be looked up on are:
AIRTEX REF # E2000 AC DELCO REF # EP286 CARTER REF # P74028 BOSCH REF # 69100 I used one on our formula car last year at WSU. Worked better than any more expensive aftermarket pump that we've used in previous years. I was just hesitant to do the swap because I didn't want to swap tunnel fuel lines. |
Ian Stott |
Dec 2 2008, 12:06 AM
Post
#8
|
Senior Member Group: Members Posts: 907 Joined: 28-January 08 From: Moncton/Canada Member No.: 8,635 Region Association: Canada |
Tangerine Racing has stainless steel fuel lines that are bent to fit, when I was talking to Chris he said he always tries to have a set in stock.
Ian Stott Moncton Canada |
SLITS |
Dec 2 2008, 08:11 AM
Post
#9
|
"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
When I installed SS lines, I ran a die across the ends (about 1/2") to give the rubber hose something to bite into when I clamped it with a hose clamp .... no problems.
|
Lo-Fi Version | Time is now: 12th June 2024 - 11:20 PM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |