Stopping on hills: Fiat Ducata 1999

[Penny Frood]

Motorhome has been imported to New Zealand; mechanics here not sure why it goes ok on the flat but stops on hills. Sometimes it starts again....sometimes not. Getting expensive being towed. Ideas please

[Billggski]

Only up hill, not downhill?

Is the Fuel tank full? Could be not picking up fuel if the level drops below the fuelpipe pick up.

[aandy]

We can only guess without a more detailed description of the problem, but I understand vehicles often have an inertia switch to cut off the fuel in the event of an impact. I've heard of them shutting off when a vehicle mounts a kerb, so perhaps a faulty one could react to gravity?

[Alanb]

1, My first MH was a 2.5 TD Talbot Express (Peugeot J5). When it was well over 10 years old, I had an intercooler fitted. On a the long journey home from the garage, the engine cut out twice, both times on uphill grades. The engine restarted immediately. I was advised to replace the fuel filter top casting, which incorporated the manual priming pump, as this could have a small air leak due to a perished diapragm. No further problems encountered subsequent to replacement.

 

As a 1999 Ducato may have a similar priming pump, it could be worth checking.

 

2. Does the vehicle stop on uphill and downhill, or just on uphill? Is it possible that there is a wiring fault whereby supply to the fuel cut off (stop solenoid) may be lost on gradients?

 

 

Alan

[Alanb]

The type of priming pump to which I was referring may be viewed here.

 

Alan

[witzend]

I have known the fuel pump in the tank to fail but engine still work by high pressure pumps suction this might not be enough for the extra demand caused by hills. With engine off can you hear the pump ticking when you turn the ign key on the low pressure feed pump is located inside the fuel tank under the passengers feet.

[Alanb]

witzend - 2019-05-06 11:08 AM

 

I have known the fuel pump in the tank to fail but engine still work by high pressure pumps suction this might not be enough for the extra demand caused by hills. With engine off can you hear the pump ticking when you turn the ign key on the low pressure feed pump is located inside the fuel tank under the passengers feet.

 

I think that given the age of Penny's vehicle, it is likely to have an engine mounted camshaft driven CAV fuel lift pump, rather than a tank fitted submersible electric pump.

 

Mechanical pumps seem to have gone out of fashion, probably because they cannot pressurise the fuel system before starting the engine. The mechanical diaphragm pumps did have two main weaknesses, leaking valves, and porous diaphragm. The faulty diaphragm was often brought to notice by fuel flowing down the cylinder block (not to be confused with engine oil leaking from the pump mounting gasket). Valve failure would not be so obvious, but could cause the problems suggested by Witzend.

 

Some of the older pumps were repairable, by using a repair kit consisting of new valves, diaphragm, and mounting gasket. Later versions could not be dismantled, and had to be replaced.

 

Is it possible that these pumps are outside the experience of some younger vehicle technicians?

 

Examples of mechanical pumps can be viewed here.

 

Alan

[witzend]

Alanb - 2019-05-06 1:35 PM

I think that given the age of Penny's vehicle, it is likely to have an engine mounted camshaft driven CAV fuel lift pump, rather than a tank fitted submersible electric pump.

Alan

 

From my experience that year did have them and I did check a parts catalogue before replying and a tank pump is available for that year