Espar BN4 heater fuel pump

[mm58]

The main fuel pump on my BN4 suddenly has stopped working. I took it out of the truck
and opened it up to inspect and clean. I applied power on the bench and the diaphragm IS
oscillating back & forth a few mm and making noise. Put it back in the truck and reconnected
it to the heater. It makes noise and vibrates but NO fuel is being pumped.

Any ideas what else I might try? It couldn't see how to disassemble it any further to troubleshoot. Are there any
inexpensive aftermarket ones that will work?
Anybody have an extra they wanna sell?

Thanks for any help

Mike

[Stekay]

When running can you feel pressure or vacuum? Perhaps just a vacuum leak upstream from the pump. Pumps all pump better than they suck.

[undysworld]

You're sure gas is getting to the pump?

Any chance you've got old fuel lines, with maybe a crack somewhere that sucks air in and prevents the pump from sucking gas? They seem to be an often overlooked item that can cause various problems.

[mm58]

I'll check the supply line for any air leaks. Thanks for letting me know about that.
I'll report back what I find.

Mike

[M Wehrman]

Mike maybe it lost it's prime? I will check in the shop for the heater that came in my Volvo, similar gas type unit but heats water instead of air. If it has one it's yours.
Mark

[mm58]

Thanks for the offer Mark. I'm still not 100% sure what the problem is. I inspected the lines for leaks and found none. Even blew out the lines with air to make sure there wasn't a clogged line. At one point when I had everything all hooked up but not bolted back in, the system came on perfectly and worked like a champ. I could hear the flame burning steady. So I figured something I did fixed whatever was wrong, and I buttoned everything back up, put the engine cover and seats back in. I pulled the heater switch on, and in true Murphy's fashion, the heater came on, but the fuel pump and flame is sputtering on and off at random intervals, rather than a steady continuous flame. It IS making heat tho, which is more than I could say yesterday. More troubleshooting to come...

[mm58]

Update: I took the plastic cover off the back end of the fuel pump and see that it is the solenoid that is making the intermittent electrical contact. This is causing the pump to cycle on-off-on-off very quickly. I checked the voltage going to the pump, and it is a steady/smooth 24v.

[mm58]

Update 2: I bench tested the pump again and I see now that the solenoid is SUPPOSED to rapidly open an close, however my problem was that is was cycling much much slower and irregular than its supposed to. So I reinstalled it again and this time it seem to be working pretty much as its supposed to. As before, I'm not sure exactly what I did to make it start working right, but I'm not going to look a gift horse in the mouth. For now I'm just gonna keep my fingers crossed and hope the fix lasts.

[dadnova]

As I have the same issue, I took my pump apart, I freed it up, however each time I go to put the cap or top on it stops working?

I think the diaphragm is too stiff from never being used, so I am soaking them to try and soften them up.

Also, I notice I need to turn the diaphragm rod out in order for it vibrate back and fourth. Does anyone know the proper turn out on the rod? 2 turns, 3 1/2 turns or just until it vibrates? Or does it really matter?

[M Wehrman]

I'm glad it works ! I do have a pump here, w/power it goes ticytickyticky! Those pumps only deliver a rate like an IV, not much pressure. ALSO! on a side note, my K died at the end of the driveway,no restart . Puttered on the trail once before . When the diaphragm in the fuel pump finally ruptured it created an air leak in the hose from the tank. No suction no go! I bypassed the fuel line to the heater pump, cranked forever and it went. I had used my heater 2wice and both times it was a bit overkill for AZ!
Mark

[dadnova]

Still cannot get this fuel pump to work, anyone know who can fix it or where I can get another one?

[audiocontr]

I am in the same scenario. Used units run around $100! I wish i would have purchased the espar heater that just sold on the forum. it included one!

Im trying to get one of the 24v Chinese fuel pumps to work - the ones designed for forklifts. So far no good. It cant produce the volume needed and maintain PSI

[spandit]

I have a complete Eberspacher BN4 24V for sale - it's new (well, unused anyway) and that comes with a pump!