heater fuel pump inop (710K)

[mockingbird812]

Looking for suggestions to repair this pump which sits behind the pass. seat. I removed the input fuel line to my heater fuel pump as it was causing my engine to starve for gas at anything under a 1/2 tank of gas. As soon as i disconnected the fuel pump the engine ran fine at all levels of gas. i expect these are pretty expensive to replace. Does anyone recondition these?

Thanks

[mockingbird812]

TTT...............thanks for any insight! Yes, it can get cold in the winter in AZ and a dedicated heater would be welcome.

[VinceAtReal4x4s]

There used to be a guy that worked on these and had some parts but my recent experience trying to get one repaired for a project truck proved next to impossible. It's much easier just to get a new heater, but they cost serious money.

[krick3tt]

Try the Webasto heaters. Got a small one that will drive me out of the cab in the winter. I put the blackout curtain down in winter to only heat the cab
It's 12V so you will need a 24 to 12 device. Gas powered.

[compunerdy]

Why do you think it is the pump and not just a fuel line leak? Just asking this based off the info you provided.

[kpoling]

Maybe the line that was disconneted at the tee had an air/vacuum leak?

[mockingbird812]

I've done a brain dump on this topic. I will have to get back into it to refresh my memory. As I recall my investigation (with help from you all) led me to believe it was a bad pump for the heater. I don't think I could hear it (the pump) running any more.

Here's the link to the thread that led me to disconnecting the fuel line to the heater...

viewtopic.php?f=4&t=4192

[undysworld]

Sam,

That old thread mentioned bad fuel line too.

If any of your fuel lines (hoses) even look old, I'd just go ahead and replace them. Fuel line is inexpensive. Old fuel hose breaks someday, even if it isn't yet leaky.

Run new fuel hose even to the heater pump, but plug the line at the heater. See if the truck runs okay. If not, then the pump is not the problem. But if the truck now runs fine, hook up the heater pump. If the problem reoccurs, then it must be the pump somehow. If the problem does not reoccur, then you cured it with new hose.

[mockingbird812]

Sounds reasonable. I'll give it a try. Thanks!

[edzz]

If I remember correctly the heater pump only runs on demand, i.e. once it attains the required pressure it quits running until the pressure on its outlet side has dropped.

[mockingbird812]

Good to know. Is that the repetitous clicking noise that I heard for short periods of time?

[edzz]

Could be. You can put fingers on the pump and feel it when it pulses. If you remove the fitting from the pump to the heater and fought it into a catch can you should get gas flow when the heater is trying to start. Also if the heater startup has timed out where is a reset switch kind of hidden on top of the heater (under the cover if I remember correctly) .

[totaljoint]

My Webasto clicks as the pump tries to prime the line and will go through repetitive cycles until the unit fires up. If it's been a few weeks since I've used it, (and the
gas line is dry), it my take 6 or 8 tries before there is enough gas in the heater to fire.
Since the pump is better at pushing fuel than pulling, the closer it is to the tank better it works.
Mine clicked more cycles when the pump was on the driver's side nearer the heater. When Jim moved it to the passenger side the unit fired up much quicker.

[mockingbird812]

The clicking is what mine does too (now I know that is the pump sound). My pump is located very close to the fuel tank and then the fuel line traverses the back of the front cab over to the gas heater behind the driver's seat. Thanks!