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Tue Mar 02, 2010 3:06 pm

There, you've heard it. It's incredibly annoying and seems to only get louder and louder. Is this a good sign my pump is going bad? I went under the bus and moved the pump around a bit to stabilize it a bit, which seemed to help - but not much.

Any suggestions? Buy a new pump? Technically, I haven't had any fuel related issues with it.

Tue Mar 02, 2010 3:08 pm

Might want to try changing out the fuel filter as you order up a new pump.

Is it mounted in the rubber bushings to keep it from vibrosis?

Tue Mar 02, 2010 3:08 pm

the pump should not be running when you turn the key, for one thing.

and the pump itself is bad or going bad for sure.

Tue Mar 02, 2010 3:15 pm

@germansupplyscott

The pump shouldn't turn on when the key is turned eh? I wonder how / why someone (previous owner) would have done that? Could it just me a mixed up wiring issue? I guess I'll take a look in my Bentley and see what I can find.

Tue Mar 02, 2010 3:54 pm

The PO probably did it because it's faster and easier to while it straight to the coil. However it is a major safety hazard because if you get in an accident and are unable to turn off the key, the fuel pump will keep pouring fuel into a possibly burning engine.

Tue Mar 02, 2010 4:23 pm

Are you saying he should install an oil pressure cutoff switch?

That's what my carter fuel pump instructions say to have.
I have the thing, but have never hooked it up.

Or is there some other only-when-it's-actually-running wire that you know about to get power from?

Tue Mar 02, 2010 4:48 pm

I think he is a FI engine and would be pwoered up via the double relay.

No coil connection required.

Wed Mar 24, 2010 12:14 pm

TheEv wrote: @germansupplyscott

The pump shouldn't turn on when the key is turned eh? I wonder how / why someone (previous owner) would have done that? Could it just me a mixed up wiring issue? I guess I'll take a look in my Bentley and see what I can find.

I better pull out my Bently too! :o

My pump starts running the second I put my key in the on position too. It makes some noise, but not that loud.

Wed Mar 24, 2010 1:12 pm

Randy in Maine wrote: I think he is a FI engine and would be pwoered up via the double relay.

No coil connection required.

For the fuel pump to run normally a coil connection is required. The fuel pump relay gets its trigger from the points in the AFM which in turn gets its power from the FI relay. The FI relay is triggered by #15 circuit coming off the coil.

Wed Mar 24, 2010 5:21 pm

If the #15 is on with the key "on" what would prevent the pump from running? Mine also is always on when the key is "on". Today I did remove the + lead to coil to trouble shoot my fuel guage and the pump did not run then with the key on. I had some other PO wiring issues but this doesn't look molested.

Wed Mar 24, 2010 8:21 pm

Sage79 wrote: If the #15 is on with the key "on" what would prevent the pump from running? Mine also is always on when the key is "on". Today I did remove the + lead to coil to trouble shoot my fuel guage and the pump did not run then with the key on. I had some other PO wiring issues but this doesn't look molested.

The pump should only run when circuit #15, the ignition circuit to the coil, is energized. One or both of the following should be happening as well. The starter is energized, or the flap in the AFM has moved and the points have closed.

You should make sure the points in the AFM are open when the engine isn't running. If this is true you likely have a bad double relay or a wiring problem.

Thu Mar 25, 2010 3:07 pm

Wildthings, thanks for the explanation. After delving deeper into the manuals I understand what you meant and sure enough, the points in the AFM were closed normally. A little bend on the actuating wire solved the problem.

Thu Mar 25, 2010 4:35 pm

You really should clean, tighten and check all the connections at the DR and starter, a little wiggle may have worked now but may not save you in the middle of nowhere or right at the middle of that bridge in rush hour traffic. Not just the terminals but where the wires enter the terminals, clean the grounds too :wink:

Thu Mar 25, 2010 5:32 pm

'Daddy, I guess I wasn't clear: the wire I bent was the acuating arm or rod that opens the contact points in the AFM (not an electrical wire). I bent it so that it would hold the points open when the air vane is closed, which it did not do before. My fuel pump would always run whenever the key was in the "on" position. Now it only runs when cranking or running, like it should.

Thu Mar 25, 2010 6:31 pm

Sage79 wrote: 'Daddy, I guess I wasn't clear: the wire I bent was the acuating arm or rod that opens the contact points in the AFM (not an electrical wire). I bent it so that it would hold the points open when the air vane is closed, which it did not do before. My fuel pump would always run whenever the key was in the "on" position. Now it only runs when cranking or running, like it should.

:shock: , So how are you sure the AFM is properly calibrated now and why was it necessary (besides the obvious issue) to bend the wire? Was there evidence that someone was in there bending things previously?
Sounds like a recipe for potential engine death, don't sleep well tonight :wink:

Thu Mar 25, 2010 7:26 pm

Yeah mine goes on when I turn the key to on too.

germansupplyscott wrote: the pump should not be running when you turn the key, for one thing.

and the pump itself is bad or going bad for sure.

Fri Mar 26, 2010 7:15 am

Amskeptic has a great explanation of the AFM here:

http://www.itinerant-air-cooled.com/viewtopic.php?...;highlight

Sat Aug 27, 2011 1:26 pm

Dug this thread up while looking to compare my noisy fuel pump with some others out there. My pump, like those above, will run when the ignition is turned on. It also seems to be somewhat noisy ... what do you think?

Recently while doing some troubleshooting for an exhaust leak (http://www.thesamba.com/vw/forum/viewtopic.php?t=478437&highlight=), my bus was idiling nice and smooth and then all of the sudden started choking and died. Once dead I could hear this steady hummmmm sound that I've never noticed before - the fuel pump. Now I can't get her to start again. It will turn over and catch for a brief moment and then die. Like I said, it was idling perfectly until it randomly choked. Wondering now if I need a new fuel pump before I can finish figuring out my exhaust issues?

Sat Aug 27, 2011 1:38 pm

#-o

Still with the "pump is on when the key is on!"

How else is there to be power if the key is not on? Is there a magical pump out there that pumps with the key in any other position yet knows some other way when to run with the motor :-k

And if your in an accident, how will the pump know to turn itself off?

I need an egghead to splain it to me dumbness. :?

Sat Aug 27, 2011 2:37 pm

Toaster on Wheels wrote: Dug this thread up while looking to compare my noisy fuel pump with some others out there. My pump, like those above, will run when the ignition is turned on. It also seems to be somewhat noisy ... what do you think?
Recently while doing some troubleshooting for an exhaust leak (http://www.thesamba.com/vw/forum/viewtopic.php?t=478437&highlight=), my bus was idiling nice and smooth and then all of the sudden started choking and died. Once dead I could hear this steady hummmmm sound that I've never noticed before - the fuel pump. Now I can't get her to start again. It will turn over and catch for a brief moment and then die. Like I said, it was idling perfectly until it randomly choked. Wondering now if I need a new fuel pump before I can finish figuring out my exhaust issues?

I just replaced my fuel pump as it died on me in the inspection lane the other day. It was noisy like yours was, and would work once it cooled off. Don't hesitate, get the replacement and swap it out. It's a 30 min job, just do it.