Help! Further Understanding the BN4...

VW's aircooled mini SUV. Great for riding in the country, or cruising the beach.
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stevemariott
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Help! Further Understanding the BN4...

Post by stevemariott » Wed Feb 11, 2004 3:32 am

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,

Capn Skully
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Post by Capn Skully » Wed Feb 11, 2004 7:55 am

According to the directions I read the switch is just a timer to shut off the heater and prevent it from killing the battery. In actual practice mine works the same way. It runs for 20 min. then shuts down the heater.

As far as the fuel pump I don't have any answers there.

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Michael Basso
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bn4 help

Post by Michael Basso » Wed Feb 11, 2004 9:31 am

Well it sounds like you are getting there,
just put 12 volts to the pump first to see if it clicks
if it does, then the heater is the problem.
if 12v alone does not fire the pump, you probably need a new one or one that is working that is.
I have them here, they are $70.

Here at things unlimited, I have two classifications of gas heaters.
ones that will fire the pump and ones that will not.

I usually place the ones that will not fire the pump in a seperate pile for later, when i have time to troubleshoot them.
Here is where it can get complicated.
And would again recommend that you get a heater manual, whether from me or someone else.
the only other assisstance i can offer to you (without going into serious detail) is to
check all fuses, clean the glow plug.
Ps we also carry heater timer switches.
they allow you to preheat your vehicle without turning the vehicle on
Hope this has helped.

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stevemariott
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Post by stevemariott » Wed Feb 11, 2004 6:35 pm

Thanks for the info guys, I really appreciate it. The pump is getting power, and makes a definite "tick" sound (and jolts a bit) when I give it power, but it doesn't squirt any fuel. The lines to and from the pump are free so I guess it's the pump itself. If I don't get it working anytime soon Mike, I'll be in touch for another pump and whatever other parts I might need.

As far as the manual goes, I sent Espar an e-mail about a week or so ago and yesterday a bunch of copied info arrived! Description, installation, diagrams, troubleshooting guide, parts list, etc. Very nice. Thanks again guys.

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Michael Basso
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bn4

Post by Michael Basso » Wed Feb 11, 2004 8:10 pm

spray some lubricant in there and let it set
if its clicking, and moving, it should be pumping
keep spraying it and giving it juice you can take it apart with a 17mm wrench and get closer to the innards,
good luck,
mike

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stevemariott
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Post by stevemariott » Wed Feb 11, 2004 8:43 pm

Thanks Mike. It's clicking, and moving - I took the ends off of it and you can see a little piston of sorts clicking forward when I give it power (moving just once). Is all of the movement and pumping (tick, tick, tick) supposed to happen when it's simply connected to power, or is the pumping motion controlled by a relay of sorts (or otherwise) on the heater unit itself? I'm getting one click, but no more clicks or pumps than that.

Thanks again,

Mattt
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Post by Mattt » Thu Feb 12, 2004 12:44 am

my understanding is that the heater itself cycles the pumps clicking. When you hook the pump up to 12v it only clicks once. Sounds like your pump is okay. Ive been told by several Thing owners that if your pump doesnt click to give it a good whack and that will often free up whats stuck.

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stevemariott
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Post by stevemariott » Thu Feb 12, 2004 3:59 am

Hey Mattt, thanks for the info. I now think my problems lay beyond the pump - my brother is helping me go over each switch and test everything one by one.

Thanks,

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stevemariott
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Post by stevemariott » Sat Feb 14, 2004 3:17 am

Hey guys, just an update - thanks to some of your online help and the troubleshooting guides I was able to diagnose the problem. The breaker points on the blower motor that control the fuel pump were dirty and a bit out of adjustment. After a few hours to tinkering I believe the fuel pump is now working as it should. I still haven't fired the whole thing up completely yet but I will set it up in a couple of days. Thanks again for all your help!

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Bob Ingman
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Post by Bob Ingman » Sat Feb 14, 2004 12:38 pm

Several yrs ago I had a faulty timer nearly melt the car (long story). Since that time I have operated the heater from a toggle. Use the gray wire to a switch and a hot wire to the other side.
If you need help bench running the unit contact Joe Timberman [email protected] . He does it all the time. Or you can call him. Hes in Redmond,Deschutes county. Best of luck. Sounds like you`re about there now. Well worth the effort especially in a bus. Bob Ingman

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stevemariott
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Post by stevemariott » Sun Feb 15, 2004 7:21 pm

Bob, I did see your post about your switch melting everything behind the dash - scary! I do like the simplicity of the toggle, I'll run that one for now.

Another update - after getting the fuel pump ticking and pumping the other night, I hooked it up to power and fuel today to bench test it. After a minute or two it made a "whoom" sound and fired up! Ahh... warm air. I still have to adjust the amout of squirt the pump puts out but at least it's working now. Now I gotta get ready for the install... I'm going to have do change things around a bit though as I'm running dual Kadrons and it won't currently fit as-is. Thanks for the help guys.

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