1974 wiring and fuel problems, need answer to the wiwing of fuel pump from relay board Options

[Matthewk]

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

[JeffBowlsby]

Help us help you!

Start by telling us what engine you have, and is everything stock, or are there mods? Also photos of the harness(es) in the car, you holding the wires you need to connect (to depict the context) would be helpful. If you will number the wires even better so we can say “wire 3 goes to the ground connection at the rear top of engine case” etc.

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[Matthewk]

So, its a fully stock 1974 1.8L

https://ik.imagekit.io/bhptmszid/IMG_1928.j...t=1758928645823

trying different ways to add an image but isn't working. so here's an image link.

the white wire (#1) I'm holding is from the main harness, close to the computer.
The two black wires (#2) I'm holding go into one connection.
then there's a green and brown (#3) , brown (#4) , black and red (#5)

[JeffBowlsby]

This diagram should answer all you questions: https://bowlsby.net/914/WiringHarnesses/doc...74-75_L-Jet.pdf

If not let me know.

Adding photos is easy, if you know rules. http://www.914world.com/bbs2/index.php?showtopic=13637

[Matthewk]

This diagram should answer all you questions: https://bowlsby.net/914/WiringHarnesses/doc...74-75_L-Jet.pdf

If not let me know.

Adding photos is easy, if you know rules. http://www.914world.com/bbs2/index.php?showtopic=13637

oh thx. can you send me a diagram for main harness too? Thank you!

[JeffBowlsby]

All are here:

https://bowlsby.net/914/WiringHarnesses/#ReferenceLibrary

[wonkipop]

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

in a 1.8 fuel pump does not run with ignition on.
runs when key goes to crank position.
after the engine fires the AFM sends the signal to the ECU via the dual relay (located under the battery box in the side of battery box support) and the AFM is telling the fuel pump to run. if engine stops running fuel pump stops running. there is hardly anything on the relay board on lhs of engine bay with a 1.8 L jet. they are not like the D jet cars.

[fiacra]

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

If it is of any help I have a fully stock, unmolested 1975 1.8 and if you need pictures of any specific areas of the engine to see how things are put together, and potentially where wires go, I'm happy to provide them. Just let me know. Jeff has already pointed you to his website, and there are tons of resources there.

[wonkipop]

and if you are looking for a really good wiring diagram in color go here.

http://p914-6info.net/Manuals.htm

you can download a copy of the factory workshop manual.
the electrical chapter has the wiring diagrams for all the cars in different forms.
will let you track and trace the quite different wiring for the fuel injection in the 1.8s.

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i had this photo lying around from another topic.
dual relay is the gizmo doing a lot of the work controlling the f p.
if its an original d r it will be silver in color.
later update replacement d r is black plastic.

[wonkipop]

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.