BN4 Heater issue, probably fuel pump, pls help troubleshoot!

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surfgringo
Posts: 30
Joined: Tue Dec 04, 2012 12:01 pm
Location: Halifax, Canada

BN4 Heater issue, probably fuel pump, pls help troubleshoot!

Post by surfgringo »

Hi, I have been trying to get my gas heater running for a while now, and STILL haven't solved the issue.

I can actually get the gas heater to run fine if I run fuel directy to the Fuel Proportioning Pump (i.e. "clicker" pump that provides a slow, metered amount of fuel to the heater, item 87 on wiring diagram). For example, if I disconnect and then place the gas line going into the clicker pump, into a cup of gas, the clicker pump picks it up and things work.

My thought was that I must be picking up air and/or some other fuel delivery issue. Having subsequently inspected (and replaced) every gas line on the vehicle, including removing the tank for inspection, I can say that the fuel lines are fine.

It turns out that there appears to be a second fuel pump (which I think is item 86 on wiring diagram), located behind the passenger seat and positioned next to the Proportioning Pump (clicker). From what I can tell, this pump supplies fuel to the Proportioning Pump, and is the source of my issues. Having taken this pump apart and inspecting, it actually appears to be functioning. Hence, I believe the issue is the electrical supply to this fuel pump.

The wiring diagrams reference 3 relays ("82") for the heater, which have connections to the heater switch, heater, and control unit. It would seem that the fuel pump of concern here is having a problem related to connection with one of these relays, or the connection to the "ignition coil" (heater, not the engine ignition coil).

Does anyone know where these relays are, or have any insights into what I might do to sort it out?
Thanks
1981 Pinzgauer 710K, 1979 VW Westfalia
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mm58
United States of America
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Joined: Tue Sep 25, 2012 10:49 pm
Location: Tucson, AZ

Re: BN4 Heater issue, probably fuel pump, pls help troublesh

Post by mm58 »

The three relays should be mounted on the bulkhead right behind the heater itself. (I'm assuming you have a "K")
Mike

'76 710K
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