I mentioned in an earlier post that I had replaced the Webasto heater and associated fuel filter, pump, and fuel line. Before I removed the old heater I verified that it was sending the correct pulsed signal to the fuel pump and that the fuel line was delivering the metered fuel to the heater end of the fuel line.

Once I installed the new heater unit and had everything connected in the boatyard, I should have fired it up there to make sure it all worked, but I didn’t. Big mistake.

On passage, when it eventually got cold enough to use the heater, I turned it on. It went through it’s normal startup sequence successfully but came up with the same “no fuel flow” error as before. For a new startup unit it may take several tries to prime the line and get the thing going. After doing that, I realized I never heard the fuel pump pulsing as it sends fuel to the unit. I open the floor panel so I could put my hand on the pump and feel whether it was pulsing during startup. It wasn’t. The new unit apparently was not sending the pulsed voltage to the pump, or the pump is bad. I thought the former because this same pump was new and had been pulsing correctly when connected to the old unit. I’d need an oscillscope I don’t have to see if the unit is really sending the correct pulsed voltage to the pump. I don’t know where to get one here in St. John’s.

Calls to Webasto tech support didn’t lead to a solution for why the pump was not pulsing. Since the heater unit itself is new, they could only conclude the pump is bad. I swapped in a second pump I got with the new replacement unit but that didn’t solve the problem so I’m back to thinking the unit isn’t sending the pulsed voltage to the pump.

At this point, as I write this, I see the problem as impossible to diagnose and fix given my current location and tools at hand. There are no competent Webasto service people around here. I may have to sail to the Arctic without a working heater which has been done before, like winter camping on a boat. I have warm clothes and a great sleeping bag. I can also get a small ceramic electric heater to provide some relief from the cold. That would turn diesel fuel into electrical power into heat. Super inefficient compared to the Webasto heater but it’s something. Still working the problem.