Fuel Flow Solenoid

[gingerwinky]

So, got home yesterday afternoon in my 24v ex-NZDF Stage 1 with at least an eighth of a tank of fuel in the rear tank.

Set out this morning and the gauge is reading zero, not a problem as it sometimes sticks however after 6 kms I pulled into a petrol station and put in 10 litres. Still no change to the fuel gauge and a few hundred metres down the road he cuts out. I switch the ignition off then on and he flashes up, 200 metres down the road same thing again.

With no fuel in the front tank I gave friend Dominic a call and he gave me a lift back to the fuel station. 5 litres of go-go juice in the front tank, he flashes up and drives off no problem.

With the ignition on, the after fuel pump wasn’t running no matter which position the fuel change over switch was in and the forward fuel pump was running no matter which position the fuel changeover switch was in.

After a bit further investigation I have come to the conclusion that it is either the fuel changeover switch or the thing behind the dash that goes “clunk” when you change fuel tanks as I have had the after fuel tank pump running this evening and the changeover “clunk” varies in time, sometimes it is immediate, sometimes it takes a few seconds to “clunk” and sometimes it doesn't do anything.

Is the changeover switch just a bog standard switch and is the thing that goes “clunk” the fuel flow solenoid and does anyone have a part number for one please.

Thanks for looking and any ideas will be greatly appreciated.

[disco2hse]

OK. Let's try this.

The switch on the dash is a standard two way switch. The whole system is controlled by a relay that I think might be behind the dash (not sure) and it may be that you can hear. However there is also another relay that the switch is wired to that controls which tank to show on the fuel gauge and that earths through the tank sender. Actually from what I see the switch is merely an on/off and the relays are either open or closed. That means when the relays are open, the switch is pointing up and is off (for our US listeners, this is how switches normally work ). This is when the side tank is connected.

As you know the fuel supply has two pumps but it only has one primary fuel line to the carbs. The flow is controlled by two solenoids that are situated under the driver's seat; one that switches over from one pump to the other when you flick the switch and the other that controls the fuel return to the appropriate tank. So,when you flick to say, the side tank (up or off on the switch) the inboard pump connected to the side tank should start and the two solenoids are set to open for fuel flow from the inboard pump and the return pipe sends excess fuel back to the side tank. Vice versa for the rear tank (down or on for the switch).

Your symptoms indicate that either one or both of the relays is kaput or that the voltage regulator needs replacing. My guess is the latter but you can stick a volt meter or ammeter on the various connections behind the dash and under the drivers' seat to see just what is going on. Note that if the side tank pump is running and the motor is not, you should eventually hear the fuel running back into side tank (takes about 30 seconds or so to pump up and return). If not or if the side tank is filling when the rear tank pump is running, then you have a bit of a problem.

Just a tip, take the steering wheel off when you need to work behind the dash. Makes life a whole lot easier.

[gingerwinky]

Hi Alan,

Thanks for the reply. The landy has been running fine since the other day on both tanks. I took the dash out and had a look at the 2 relays in there pt no.s Bosch 332 209 203. They were modern plastic ones with no obvious damage but I replaced them anyway.

This happened to me last year and again the fault sorted itself out.

Thanks for the reply

Andy

[disco2hse]

OK. Good luck.

Voltage regulator is a pretty cheap fix too.