TheSamba.com :: View topic - Fuel pump won't turn off with key on engine off.

Sun Aug 17, 2014 1:16 pm

I have a 1983 Vanagon 2.0L air cooled automatic. It runs well, however the fuel pump won't turn off with the key in the on position and the engine off. Isn't the pump supposed to cycle for a few seconds when you turn the key on and then shut off? I know that once the engine starts the AFM will keep the fuel pump running. If I want to listen to the radio when just sitting with the engine off and the key on it's rather annoying to have the fuel pump constantly running. I have already installed a new fuel pump and a new fuel regulator.

Sun Aug 17, 2014 1:19 pm

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Sun Aug 17, 2014 2:05 pm

Not positive, but I think this may be by design. My '81 behaves in the same manner.

VW did not supply an "accessory" position but you can rewire your stereo to be on a non-switched circuit (cigarette lighter, etc.) if you so desire.

You just need to remember to shut the stereo off every time so you don't kill your battery. I've had mine wired this way for years and haven't had that happen yet.

Sun Aug 17, 2014 2:42 pm

If the pump is not turning off, that means that the fuel pump "safety" switch located inside AFM is closed (engaged). Open the AFM box, and look for an arm (boom) that touches/pushes/engages onto a contact. Bend ever so slightly, so when engine is off, it will disengage the contact/open circuit.

L-Jetronic does not do any kind of priming, afaik.

Sun Aug 17, 2014 8:43 pm

Great info. to know.... you are definitely the man with this fuel system.

a1fa wrote: If the pump is not turning off, that means that the fuel pump "safety" switch located inside AFM is closed (engaged). Open the AFM box, and look for an arm (boom) that touches/pushes/engages onto a contact. Bend ever so slightly, so when engine is off, it will disengage the contact/open circuit.

L-Jetronic does not do any kind of priming, afaik.

Sun Aug 17, 2014 9:19 pm

The fuel pump didn't used to stay on like this but I was having another electrical issue with the engine, a short while back, and I had the AFM and the CPU checked out. Turned out the AFM was fine but the CPU was faulty and so I had the CPU rebuilt. It fixed my other problem but most likely, when they were poking around inside the AFM, they must have bent the contacts out of correct alignment. I'll pull the lid off in the next few days and check it out and then I'll report back. Thanks for the suggestion. These forums are priceless.

Sat Aug 23, 2014 10:49 pm

The problem has resolved itself! I didn't have a chance to remove the Air Flow Sensor lid but today when I turned the key on the fuel pump didn't run until I actually started the engine. Maybe the contacts for the fuel pump in the AFM were just a little sticky from not starting the engine for several months and after taking it for a short drive they came un-stuck. Anyway, it's working properly again, at least for now!

Sun Aug 24, 2014 1:04 am

cybervette wrote: The problem has resolved itself! I didn't have a chance to remove the Air Flow Sensor lid but today when I turned the key on the fuel pump didn't run until I actually started the engine. Maybe the contacts for the fuel pump in the AFM were just a little sticky from not starting the engine for several months and after taking it for a short drive they came un-stuck. Anyway, it's working properly again, at least for now!

The flap in your AFM may be sticking and thus not returning all the way. You might want to spray some cleaner down the bore of the AFM and see if that helps keep it moving freely.