Frequency Valve and Fuel Pump not shutting off

[AugustneverEnds]

So like the title says I switch the ignition off but those two keep running. I pulled fuse 7 to stop them. Any ideas where I should be checking first? Thanks as always gang

[Bitsyncmaster]

RPM relay if stuck on will do that.

[AugustneverEnds]

Simple enough to check. I think I have an extra one laying around. I'll swap 'em and see what happens.

[AugustneverEnds]

So I plugged in the extra RPM relay and the pump and FV are turning off with the ignition. There is a difference between the old RPM relay and the newer one I installed, the FV buzzed all the time with the old one and now it does not when the key is in position 2. The car starts fine either way and the FV started buzzing when the engine was running. Are there two varieties of RPM relays out there? The original one in my car is probably the one it left the factory with. The replacement came with the DMCH relay update kit.

[Bitsyncmaster]

The original relay had two contacts on the relay and sometimes the contacts would not both mate. I've seen a few NOS relays never power the lambda (FV). I've not seen any core returns have stuck contacts but the relay pins mostly break the solder joints and then the pins can move.

Now most of the RPM relays use one contact and therefor both the pump and lambda either work or not.

[CFI]

I highly recommend bitsyncmaster’s RPM relay. It’s light years ahead of both the factory and Bosch replacement relays. As you’ve seen, it’s a critical part of the car.

[AugustneverEnds]

I highly recommend bitsyncmaster’s RPM relay. It’s light years ahead of both the factory and Bosch replacement relays. As you’ve seen, it’s a critical part of the car.

Every time my car does something like this I am amazed it has covered as many miles as it has and as, relatively for a D, reliably as it has. I really do need to ditch the antiquated relays and buy Mr. Dave's.