Help! Further Understanding the BN4...

[stevemariott]

After a few weeks of tinkering around and cleaning up the BN4 I picked up from Ebay, I finally got around to bench testing it tonight. Fuel, battery, wiring, etc. Well, the fan blows a mild hurricane through the ducts, but no fire. First it seems the fuel pump isn't getting any power, so after some dirty contact cleaning it appears we're getting power. But still no fuel... it seems the fuel pump is stuck or seized up. I understand that old fuel in the pump would cause it to gum up and stick in there... is there anything I can do to possibly free this up? Soak it in something? Or am I out of luck? What are my options as far as finding a replacement pump?

Also, the heater I purchased didn't come with a timer/switch. As per some online instructions I found I wired it up with a standard on/off toggle switch and it seems to work okay like this. As I don't have the stock switch I don't quite know, so could someone explain how the factory timer/switch works? I understand that it has a timer that sets for 20 or so minutes while the car is off, but the switch also has as a rheostat (?) to control the temperature of the heater? Is this right? So this will be advantageous over the toggle switch I'm using right now?

My application is a '68 bus, and this is the late BN4 with the bowden-cable operated thermostat control mounted in the ductwork.

Any information anyone can provide is much appreciated. I'm new to gas heaters and need all the help I can get.

Thanks,
_________________
1963 Manx copy
1968 Bus

[7thing3]

I had a similar problem when I restored my Thing. I imagine the heater hadn't been used in years. Squirt some WD-40 into the fuel pump and lightly tap it with a hammer. then hook it up to a 12 volt battery but remember it doesn't take a constant current, rather it is intermittently supplied with +, so hook up the - side and just touch the + side. You should hear a click sound and some fuel squirting out. You may have to repeat the procedure to "loosen up" the crud. I suppose a liquid wrench or carb cleaner type of product would also be helpful to free up any seized parts. Hope this helps. Don't forget to plumb a fuel filter in line for the heater--before the pump.

[fathing]

Hi, I can offer you the following for your timer problem:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?Vi...MESSE%3AIT

This Eberspächer heater timer has 3 wires (red, brown and yellow) red is continuous 12V+ (30), brown is Ground and the yellow wire is the switched circuit. Where you attached your toggle switch you now attach the yellow cable. Now you can programm the clock to switch on the heater for you, it has a instand on switch as well. The clock will automatically switch of the heater after 2 hours to safe your battery.

Best regards

Dominique