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more fuel problems..

2756 Views 18 Replies 6 Participants Last post by  hoppybopm
i have started this one as a few other original fuel problems have been solved.

i have a problem.

i dont think its air ingress but im not sure.

i have removed the heater and bought a new primer top, also replaced the return pipes in the injectors and the end cap. but i still have a pressure problem.

i primed the fuel to solid but 10 mins later i could prime again.

the only original pipe i have left is the one going from the primer to the injectors.

anyway. i think there is a fuel leak back to the tank. im not sure which way, so i have 2 questions...

1) if i prime could it be leaking forward through the fuel system.


2) could it leaking back through the filter?

what would the next course of action be?
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The fuel can't be pushed any further than the fuel stop solenoid unless the ignition is on, and it won't go back to the tank via the return line because the pump isn't moving/spinning. There's a one way valve inside the primer head that is supposed to prevent fuel from running back to the tank, so assuming that all is well with that then I would not suspect that. There are so many places for air to enter the fuel system, it's unreal. We all hear about the leak off pipes and the primer pump because these are the most common places for air ingress, but you also have the banjo nuts on the fuel supply and return pipes on the injector pump, these have copper washers that have to be replaced each time they are disturbed, the top cover of the pump and the throttle arm both have rubber seals, as does the advance solenoid, and the boost compensator diaphragm, either of these could be letting in air. If the motor starts good and runs good then I wouldn't worry to much, but if you that you still have an air ingress problem that's causing prob's then you could put a piece of clear pipe on the return side of the pump and look for bubbles there.
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ill take a pic of my changes later. can you please change the pic on further bits i can change to replace.

i dont know if there is air ingress as the one clear pipe i have from the tank to the primer (not all the way though, just the part where i removed the heater) no air in there.

omg this can become obsessive..

when i start the car it seems to run like its being starved of fuel, but as soon as i blip the peddle it runs fine.
Go for it, I'll have a look at your pic and see what else can be done.
the stuff in green in the bits i have changed.
red stuff i have not but am going to. the rest i dont know what else can be changed.

i am also going to [color:red]try[/color] and find a new base for the primer and buy new fuel filter.
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i have now replaced the pipe above with clear braided stuff..

i can actually see the air bubbles go into the system from the fuel filter.

i need to replace the filter and seals and base plate.
I had an air leak on the base plate of the primer pump once, took me ages to find it, but it turned out to be the drain screw on the base plate, only a small leak but it caused huge problems. In the end I just removed the screw and filled the hole with metal putty, the car had no problems from that point on. Are the bubbles that you can see big, or a consistent stream of very small ones?
it depends on how hard i accelerate.

on idle its small line of them.
hard acceleration large almost constant stream of them
sounds like your primer pump!the more you rev it the more its sucking in.from the bottem its lots of small bubbles from the top its big masses of bubbles it not dragging through the fuel in the filter to thin them out. when you bleed the fuel into a new housing the inlet/outlet are dry till the fuel gets into all the rubber parts inside.the first 6 or 7 preses of the pump splits the insides when dry i allways sit mine in a tub full of derv for an hour or so to soak in. get rid off the fuel heater too they are pants.hope this helps
"i have removed the heater and bought a new primer top" i have already done this..

so from what you said i need another new primer pump top.
Was it a genuine Ford primer, I had some right problems with mine, but I got one from Fords including all the seals, infact it came as a fully assembled unit.
the pipe from the tank to the housing try putting a length of clear pipe on about the same length as the filter to the pump this will give you a better view for bubbles from the tank,and if that one is clear put the little one back on, its very hard to see them in the small pipe.when you take the housing back off to replace the filter block the inlet outlet on the housing and hold the primer close to your ear and press slowly you will hear it sucking if broken.when i put a new filter on i hand turn the bolt head tight and with very little presher a turn with a spanner untill the base will not turn refit every thing and start the car then give it a little turn or two,the presher in the housing helps to seal it,they are a very poor designe realy
right ok think i was a little premature about posting before..

as it turn out the large bubbles were extra air in the filter that i didnt get out.

it is now fine apart from a few tiny bubbles so the bottom will need replaceing.
Check the rubber rings top and bottom of the filter as well, if these arent changed they go hard and can let air in.
yes i know i changed all the seals last month but i think one might be twisted!

ill buy new filter and get the seals from there!
does anyone know what is causing jerky running on constant rpms around 2500rpm? mk2diesel
your best of setting a new topic away matey you will get a better responce as more peaple will look at new topics :driving: sorry but ive no idea but iam sure ive read something like this on here befor? might need to go back in time for your ansewer :smoking:
yes i am pretty sure its the cold start solenoid.

i do need to get a new one of these but it will cost about £50 to get one!
try the brakers yard first you will need a small handeld shifter spanner that opens over 27mm thats the size of the nut best just cut the wires and rejoin too.put it in your pocket and take a rad pipe to say thats whot you need job done :banana:
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