I bought a non-running 1974 1.8, while I get spark the fuel pump refuses to run through the dual relay. Tested every way I know how and I can get the power side to actuate (click), the fuel pump side is dead.
My question, has any one done a work-around using the standard Bosch 5 pin relays?

There’s a lot of information over on ThaSamba on the subject. I believe the relay is the same for all LJet cars. Here’s one good example.

https://www.thesamba.com/vw/forum/viewtopic.php?t=362547

R Atwell has diagrams for a potential work around.
i have not had to do anything yet. fingers crossed - but i guess i will be doing this if i have to one day. unless some pop up for sale.

https://www.ratwell.com/technical/DoubleRelay.html

looks like a few folks have taken up ratwell's diagrams.

The relay is the same for all 1.8L 914s. It is not the same relay used on all L-Jet cars. The VW implementations, and the 912E use different relays from the 914 version, and they are NOT interchangeable.

See diagram of relay board. Ground spade III
The pump should run

Jim, the L-Jet dual relay being discussed is on the other side of the engine compartment.

I realize that. This is a bypass. FP runs continuously when key is on.

Gotcha, I've used that technique for carbed cars but never on injected.

Will the fuel pump run if you connect it direct to 12V?

It could be possible the relay is fine, but the pump is dead

that may be so. but.......

i have the black plastic superceding relay. bosch 0 333 514 120 that r atwell uses/discusses on his website. 74 1.8.

been on car since 89. got the metal one replaced in chicago. i did not do it myself back then (L Jet EFI was something i looked at and my eyes glazed over ).

there was a little mod they do with the wiring. @Van B was on to it with his car and there was a discussion about it a couple of years ago on a thread Van was running.

so its for sure that what r atwell has diagrams for on his website must work in some way for the 914 too as its exactly the same relay being used.
i think 0 333 514 120 is the much later superceding part that replaced the original earlier metal ones and i think the black plastic one is universal for the L jet in all the VW applications of that era. ie the L jet beetle. L jet 412 and some of the buses.

as to bypassing the fuel pump shut off. all good and well. but it is an inbuilt safety design that came with the L jets. fuel pump cuts off if engine stops running even if ignition is on. seems to me if you can figure out the way to make two relays into the dual relay set up as per ratwell diagrams its a good way to go rather than make a degraded system so to speak. its probably what i will do if the one on mine gives up the ghost. will try and make one.

this is the one that is in my 74 since 1989.

Click to view attachment

even back then it was not a straight plug in replacement for the orig metal one.
there was a little wiring mod they did.
VW mechanics had the work around for this relay replacement and knew how to do it without thinking.

a lot of L jets these days would have this plastic replacement though just as many still probably have the factory original.

i'd never stopped to figure out there was a wiring mod for it to go in but Van B figured it out as to exactly what got slightly changed to do it.

but of course these days the once available plastic relay has become unobtanium.
bosch stopped making it in 2013. last time a batch was run.

** I installed an under dash switch to activate this bypass- Just in case!

The fuel pump will run if I manually close the relay (cover off) or if I jump the terminals on the relay board.
Yes the fuel pump runs.

Does the pump run if you open the air flow meter flap?

No. I have continuity when I move the flap but no action from the relay.

easier to just repair yours and keep the factory wiring and function. Our man sean Buckley repairs them all of the time for our customers

As George has said this relay can usually be repaired. The most common failure is the resistor followed by a diode. With an ohm meter and some basic electronics skill the relay can be made to work again.

Click to view attachment

That is either a bad relay, or the wrong relay. The circuit from the Air flow meter to the relay has the pin in a different spot on some of the relays.

If you have the incorrect relay, you can always move the pin in the plug.

I have what I believe is the original relay.

The beauty of our 50 y/o machines AND the group of guys and gals here.

Hope you get her going soon

Thank you, I’m having a blast working on the old girl

Thats right Wonki! My night shift troubleshooting partner!

You and some of the heros of this forum were helping me work through various issues and we got onto the relay wiring about here but then we moved on to bad quality CHT issues. The thing we learned is that the relay we both have works fine, but requires an external jumper wire from 88z to 88y. None of us could confirm if the original was wired the same of if it was an internal connection.

Though we might get an answer on this thread!

I’m going to give it a shot. I’ve studied the pinouts, schematics and the drawings on the other sites and feel I have a good understanding of the circuits and operation. Waiting on electronics from the jungle site.

I would like to send it in for repair, it appears the windings on the FP coil is broken. The resistor as well as the diodes test well.