Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > Porsche 914 & 914-6 Technical Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Jan 2014
Location: Pittsburgh, PA, USA
Posts: 18
Garage
No Fuel Pressure

I'm new to my 914 and I'm trying to debug my fuel system. 1972, stock FI AFAICT.

Symptom: fuel at the pump, rail isn't getting pressurized at startup.

I hear the fuel pump start up for a second when I turn the key to the on position, so it may work, but I'm not sure. I've been trying to open the air-flow meter flap, which I've read that I need to do to activate the pump, but I'm not sure I'm moving the right thing. Is this it:
https://m.flickr.com/#/photos/avocado_tom/14472480113/

I'm guessing my next step is to remove the outlet line from the fuel pump to see if anything comes out when I initially turn the key, but I'm looking for debugging guidance...
Old 06-18-2014, 08:10 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered User
 
Join Date: Jul 2012
Posts: 426
confusion here. a 1972 car should have D- jet injection, the airflow meter is not in a D-let car, only on L-jet cars. So what do you have for an injection system, D-jet or L-jet?

Certainly check the pump for flow, do not run the pump for long if it is not flowing, gas flow helps keep it cool.

the pump could be hooked up wrong, re-check all connections, make sure tank outlet is not clogged, there is an internal wire mesh filter inside the tank, replaceable by removing the outlet fitting. also of course check the inline filter that is right before the pump, mounted on the lower forward engine fire wall (access near pump).

PS what is AFAICT?
Old 06-18-2014, 09:38 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Join Date: Jan 2014
Location: Pittsburgh, PA, USA
Posts: 18
Garage
Thanks for responding! I honestly don't know what FI system I have. I picked this up as a project that someone else had mostly put back together and I was told that it was the stock engine. I thought I had read that to test the fuel system in the '72 I should toggle the AFM, but I must've gotten mixed up and been looking at the wrong FI manual.

I do know that the pump is getting fuel because I drained the tank (and line) and refilled it and I can see fuel in the line at the pump. I think I replaced the filter already with a new one, but I'll verify.

I know that the pump is hooked up correctly insofar as I hear it power up when the key is first turned on, but I'll verify the hoses are hooked up to the right ports. I'll verify the wires are connected to the right spades too, but I'm pretty sure they are. Are there other things I should check?

And, AFAICT is "As Far As I Can Tell".
Old 06-18-2014, 05:08 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
beatnavy's Avatar
 
Join Date: Sep 2013
Location: Northern VA
Posts: 434
Garage
As mentioned, it seems like you may be confusing D-Jet and L-Jet concepts. If you have a stock '72 FI, it's D-Jet, and the "air flow meter flap" is not a factor. D-Jet fuel pump is primed when ignition is one and you should have fuel at the rail. A couple of questions:

1. Can you take and post a picture of your engine? That may help settle it.

2. Has the car been sitting for some length of time? Residual fuel in tank and lines may have gone to sludge. Your pump may operate, but it's not going to pump tar. May want to disconnect line at fuel filter and see what comes out (if anything).

Good luck!
Old 06-18-2014, 06:13 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Jan 2014
Location: Pittsburgh, PA, USA
Posts: 18
Garage
Hi beatnavy,

Several engine photos can be seen here: https://m.flickr.com/#/photos/avocado_tom/sets/72157640042666674/

The engine has been sitting for a while, so one of the first things I did was drain the tank and lines. So I know the new fuel is good. I also know fuel is getting past the filter, as I can see it in the line. Looks like the next thing to check is whether anything comes out of the pump when I turn the key...

Thanks!
Old 06-18-2014, 06:56 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Administrator
 
Dave at Pelican Parts's Avatar
 
Join Date: Dec 1969
Location: Silly-Con Valley
Posts: 14,061
Garage
Send a message via AIM to Dave at Pelican Parts Send a message via Yahoo to Dave at Pelican Parts
The component you show in your picture:



is the throttle body.

The D-jet does not have an air flow meter. The D-jet bible can be found here: Brad's '70 914 2.0L . Read and understand it to understand your fuel system better.

Is it possible you hooked up the hoses wrong? The pump should be labeled S, D, and R. The S goes to the fuel filter and then the tank, and is the feed from the tank to the pump. The D is the pressure connection, and it goes to the right-side fuel rail. The R is the return, and it goes to a Y connector that goes to the fuel pressure regulator and also back to the tank.

Is it possible that you hooked up the wires backwards? They shouldn't, if you kept them in the body of the plug, but if they are just plugged in as wires then you can switch them.

--DD
__________________
Pelican Parts 914 Tech Support

A few pics of my car: http://www.pelicanparts.com/gallery/Dave_Darling
Old 06-18-2014, 08:09 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Registered User
 
Join Date: Jan 2014
Location: Pittsburgh, PA, USA
Posts: 18
Garage
DD,

I will check all of the above this weekend when I'm home. (Currently out of town for work) Thanks!!
Old 06-18-2014, 08:45 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Registered User
 
Join Date: Jan 2014
Location: Pittsburgh, PA, USA
Posts: 18
Garage
Ok, it looks like the hoses were set up right and that there's flow through the filter. I'm guessing the pump is the issue ... It's not firing up when I turn the key on anymore and the wires are still in their plug, so they should be in right.
Old 06-24-2014, 09:48 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Registered User
 
porschetub's Avatar
 
Join Date: Oct 2009
Location: New Zealand
Posts: 1,384
Garage
Blocked filter,yep you may have changed it but it may be blocked with old cr#p,your pump should run smooth and make little noise,it not it is worn out or is trying to suck thru a bad filter.
__________________
1985 944 2.7 motor,1989 VW Corrado 16v,57 project plastic speedster t4 power,1992 mk3 Golf,2005 a4 b7 qt avant 3.0 tdi,1987 mk2 Golf GTI,1973 914,2.2t to go in.
Past cars, 17 aircooled VW's and lots of BMW's
KP 13/3/1959-21/11/2014 RIP my best friend.
Old 06-24-2014, 11:33 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 09:19 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - 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.