911 Frequency valve wont stop buzzing

[Blagave]

I have a 1980 911 SC with 3.0 motor. The car has been completely re-done and has the original wiring.
Just recently, the frequency valve will go on and off with the ignition off and sometimes runs enough to kill the battery.
I took the car to a professional mechanic to have the CIS tuned and adjusted hoping that would solve the problem and it did not. The mechanic was confused as well, since the valve should not have power when ignition is off.

Just hoping someone has had something similar happen and can point me in the right direction

[john walker's workshop]

Stuck relay? It's under the passenger seat, in front by the tunnel.

[Blagave]

Originally Posted by john walker's workshop

Stuck relay? It's under the passenger seat, in front by the tunnel.

Thank you

[boyt911sc]

Blagave,

Next time you have the FV running with the ignition off, pull out the FV relay beside the ECU under the passenger side seat. If the culprit is the relay, pulling it out would disconnect the power from fuse 18.

Tony

[Blagave]

Originally Posted by boyt911sc

Blagave,

Next time you have the FV running with the ignition off, pull out the FV relay beside the ECU under the passenger side seat. If the culprit is the relay, pulling it out would disconnect the power from fuse 18.

Tony

Thanks for the info. I pulled the relay today and the motor runs like crap without the relay, like it should. I believe the relay is bad, you can hear parts rattling around inside and when installing, it make the engine run either crisp or terrible just by touching it.
I went to Porsche, Audi, Volkswagen, Napa and Pep boys today non of them have the proper relay and the standard style does not work, so I ordered one form our host.

[jjeffries]

Blagave, i have the same issue. Did your new relay fix the problem?

[jjeffries]

Just re-read your symptoms. My car (82 SC, stock) is one I bought disassembled last year, engine out, and I am now reinstalling the motor for the first time. With ignition on and FP relay jumped or air meter arm lifted, the fuel pump runs (ok) but the frequency valve buzzes loudly. Is this normal? Thanks in advance, John in CT

[gazzerr]

Here's the relay you need - towards the end of the page. Worked fine for me:

1982 Porsche 911 SC Targa - Switches, Motors, Relays, Fuses & Wiring - Page 5

[boyt911sc]

Originally Posted by jjeffries

Just re-read your symptoms. My car (82 SC, stock) is one I bought disassembled last year, engine out, and I am now reinstalling the motor for the first time. With ignition on and FP relay jumped or air meter arm lifted, the fuel pump runs (ok) but the frequency valve buzzes loudly. Is this normal? Thanks in advance, John in CT

John,

There are two (2) important criteria needed for the operation of a good working FV relay.
1). Power from terminal #30 or FP running.
2). Power from fuse #18 to supply power to FV relay.

If the FP is running, the FV should be running too. Or vise versa.

Tony

[jjeffries]

Thanks Tony. That's what I have going on (FP and FV on at same time), glad it's correct. John