loosing prime in diesel prado. can you help? (1 Viewer)

[nordic venture]

i'm loosing the prime in my 1kz-te prado to the point that i need to pump the priming lever on the fuel filter to help it start. i disconnected the filter and vacuum tested it and it's ok.

i've also run a gravity feed of diesel straight into the injector pump left it over night and it starts perfectly. however, when standing i've noticed that fuel slowly drips out of the return hose (the banjo fitting on top of the injector pump) to the point that if left long enough the gravity feed empties itself into a bottle placed by the outlet on the pump (once hose removed).

am i right in thinking this isn't right and would be the reason i'm loosing the prime??

also, without having the cash to have the injector pump removed and serviced, what can i do about it??

many thanks.

 

[roscoFJ73]

also, without having the cash to have the injector pump removed and serviced, what can i do about it??

many thanks.

Why not replace the 5c Oring in the banjo??

 

[nordic venture]

the fuel is leaking out of the pipe (as it's supposed to when the engine is running) not the actual banjo itself. to me this suggests a small leak inside the pump itself. i have removed the fitting (banjo). it consists of a hollow screw with a spring loaded ball valve inside. it appears good.

would i be right in thinking that fuel shouldn't leak (even very slowly) into the return lines when the engine isn't running?

thanks for your input.

 

[nordic venture]

anything wrong with fitting a fuel shut-off solenoid close to injector pump on the return side? my thinking is that this would stop the fuel from running back into the return line when the engine isn't running and help keep the prime in the pump itself. wired to a switched live it would open when the ignition is turned on and then run as normal.

i guess the proper way to do it is have the pump itself overhauled but over here that's big bucks especially as fuel alone is around $11 a gallon (£6.20 in my money)

any thoughts on this?

 

[roscoFJ73]

the fuel is leaking out of the pipe (as it's supposed to when the engine is running) not the actual banjo itself. to me this suggests a small leak inside the pump itself. i have removed the fitting (banjo). it consists of a hollow screw with a spring loaded ball valve inside. it appears good.

would i be right in thinking that fuel shouldn't leak (even very slowly) into the return lines when the engine isn't running?

thanks for your input.

anything wrong with fitting a fuel shut-off solenoid close to injector pump on the return side? my thinking is that this would stop the fuel from running back into the return line when the engine isn't running and help keep the prime in the pump itself. wired to a switched live it would open when the ignition is turned on and then run as normal.

i guess the proper way to do it is have the pump itself overhauled but over here that's big bucks especially as fuel alone is around $11 a gallon (£6.20 in my money)

any thoughts on this?

I think the fuel still coming out the return line is normal as the pressure inside the pump slowly equalises to atmospheric pressure.
If you are still concerned about it,modify the fuel line so the leak must run uphill. Obviously the fuel cant run uphill ,so the fuel would stay in there

Is your primer pump ok? They can leak and let air in

 

[nordic venture]

thanks. yeah the primer pump is ok. i vacuum tested it and it held.

looking further still i have noticed that fuel is leaking past the threads on the overflow screw where it fits into the injector pump body. this then goes up the outside of the screw, into the banjo fitting and out the fuel line. i would have thought that the purpose of the screw being hollow and having a spring loaded ball bearing was that when pressure built up in the pump it pushes against the ball bearing, compresses the spring, flows into the hollow screw and out the pin hole near the top into the return fuel line?

if so and this is the cause of my troubles, what would be the best thing to seal the threads?


many thanks.

 

[roscoFJ73]

thanks. yeah the primer pump is ok. i vacuum tested it and it held.

looking further still i have noticed that fuel is leaking past the threads on the overflow screw where it fits into the injector pump body. this then goes up the outside of the screw, into the banjo fitting and out the fuel line. i would have thought that the purpose of the screw being hollow and having a spring loaded ball bearing was that when pressure built up in the pump it pushes against the ball bearing, compresses the spring, flows into the hollow screw and out the pin hole near the top into the return fuel line?

if so and this is the cause of my troubles, what would be the best thing to seal the threads?


many thanks.

I think the screw your talking about is the overflow screw. It has a gasket above the banjo and below. They should stop any fuel coming out,if not replace them.
Those gaskets are never reused by the pros once they have been undone.

I dont know if you could use thread tape. It might deteriorate inside the pump.