Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
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.
 

Welcome Guest ( Log In | Register )

> 1974 wiring and fuel problems, need answer to the wiwing of fuel pump from relay board
Matthewk
post Sep 25 2025, 06:46 PM
Post #1


Newbie
*

Group: Members
Posts: 3
Joined: 8-October 24
From: Washington state
Member No.: 28,398
Region Association: Pacific Northwest



Hello, I've been working on a 1974 914 for the past year. Ive rebuilt the motor since the last owner overheated it somehow (no compression). Ive put the motor back in and I cannot seem to remember where any of the small female ground connectors go from the wiring harness. Like the many different small ones in the transmission harness that goes into the engine bay. And the two near the distributor. I remember there being a ground connection under the intake but I dont know which ones go there. Ive been trying to read wiring diagram but I cant understand it what so ever because nothing is labeled. So I'm just guessing reading it.

My other question is, what do I do about the fuel pump not working. If you put power externally it works, but from the relay board it just has no power past it. The power supply relay clicks, but fuel pump does not. There was power to the fuel pump relay pins a couple days ago now there isn't. Maybe I'm just tweaking out. Last owner has a whole bunch of fuel pump related things highlighted in the book he gave me. My brother read that the relay board could go bad but I doubt it.

In another post, I read that you need to switch the 25 amp fuse for an 18. It solved someone else problem of blowing relays. Ive swapped relays around and they work in other spots. So it isn't bad relays.

Hopefully someone understand what I'm asking and has the solutions for it.

thx
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
 
Reply to this topicStart new topic
Replies
wonkipop
post Sep 27 2025, 01:28 PM
Post #2


914 Guru
*****

Group: Members
Posts: 5,076
Joined: 6-May 20
From: north antarctica
Member No.: 24,231
Region Association: NineFourteenerVille



forgot to mention.
you can test the fuel pump is running by pushing the flap in the AFM mounted to the air cleaner with the ignition to the on position. it should run.

easiest way is to unclip the top of the air cleaner, hold it up in the air a bit and push the flap with your fingers. gently. or use a screwdriver to push it if your fingers cant get in there far enough. (IMG:style_emoticons/default/beerchug.gif)


as to relay board. 1.8s only have one relay in there. for the heater blower fan.
the other sockets are left empty.
fuse = 18 amp normally. (25 amp if you have a heated rear window). i dont know much about those, no heated rear window in mine.
dual relay for L Jet under battery replaces all the relays normally on the board for D jet cars.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Posts in this topic


Reply to this topicStart new topic
2 User(s) are reading this topic (2 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 28th September 2025 - 05:24 PM
...