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Fuel Supply Issues, leaning out, fuel pump, fuel filter

Posted: Sun Nov 22, 2009 8:24 pm
by phat-customs
Have a 1985 Shorty Pajero with 2.6 Astron Carby, have been chasing a fual supply prob thats very intermitant, and have traced it back to not enough fuel in the float bowl thus causing a lean out and stalling the engine.

Ive traced it back to the fuel pump not supplying enough volume/pressure to fill the float bowl and instead taking the easy way out and running back to the tank via the return line.

I have a Montero Workshop Manual and its a little different to the pajero it seems, slightly different Carbs and Poloution gear, but it does mention that there is an In-Tank fuel filter, can anyone confirm this is the case and that the Aus delivered version has an intank filter???

Would a blocked filter be the cause of the pump not supplying enough fuel given that to rectify the problem I have blocked the Carb to Tank return line and that has bought the level of fuel in the bowl back up.

does that factory fuel pump design give trouble

and lastly,

Can i replace the manual pump with an electric one, and a: not run a return line???

Posted: Mon Nov 23, 2009 8:02 pm
by steverisingsun
THe fuel return is not the issue.
Do an output test of the fuel pump, start the car with the fuel line to the carbie going into a measuring bucket, time how long it takes to pump out a litre.
Check that the right pump outlet is being used, some pumps have a restrictor on the outlet that feeds the accelerator pump on the carbie.
Change the soft hoses that feed to the pump.
Steve

Posted: Mon Nov 23, 2009 8:56 pm
by phat-customs
steverisingsun wrote:THe fuel return is not the issue.
Do an output test of the fuel pump, start the car with the fuel line to the carbie going into a measuring bucket, time how long it takes to pump out a litre.
How long should it take to pump a litre??? and for that matter, how do I run the car for a period of time with the fuel line dosconnected!?! LOL

I have found my copy of the Gregorys manual for it and it says to put a "T" peice in the pump line and check the Pressure, but I have no test gear for that kind of thing.
Check that the right pump outlet is being used, some pumps have a restrictor on the outlet that feeds the accelerator pump on the carbie.
Change the soft hoses that feed to the pump.
Steve
Have had the car for several months now, and the problem is only just rearing it head now, so I can assume that its connected correctly, and it doesnt "look" that old, its still very shiny new looking

Have also confirmed with the Gregorys that there IS infact an intank fuel filter which is very odd for a Carby car, could this also be giving trouble and causing my issue?

Posted: Tue Nov 24, 2009 7:18 am
by steverisingsun
Most pumps will put out around 3/4Lt every minute, the car will run on whats in the bowl. It may not run for a minute but if you time it you should be able to work it out. To not check that the restricted outlet is not being used as the main feed, would be foolish

Posted: Tue Nov 24, 2009 5:27 pm
by phat-customs
Checked the connections on the fuel pump and they are as per the manual.
havnt checked the flow yet, perhaps a job for the weekend.