Why no fuel coming through pump?

[Shaundon]

My 1.9dh(dg) wont start and after much investigation i have tracked it down to the fact that the fuel is not being pumped to the carb. If i drible petrol down the throat of the carb she kicks into life fine but as soon as you dont she cuts out as the pump doesnt seem to do its job. I took the pump off and the push rod goes up and down fine and if i hand pump by pressing the lever on the bottom of the pump from a jar of petrol in the engine bay the pump seems to work. However there seems to be no petrol reaching the inlet to the pump from the tank. I changed the inline filter but that made no difference. Could air bubbles stop the pump from pulling the petrol up from the tank? If so how do i get the petrol flowimg again.?

[billy739]

make sure there is no blockage in the pipes/tank

or there is not an air leak in the pipes

the pump can become weak , so although looks ok may not be efficient enough .

clamp the pipe at the tank output and suck just before the pump with your mouth and see if theres a leak.

[Shaundon]

Wont i get a mouth full of petrol doing this?

What should i clamp the pipe with?

[billy739]

pipe clamp/mole grips

if clamped you should not be able to suck anything!

if you can suck there is a leak in the pipe which will cause the pump to suck air not fuel

[Shaundon]

replaced the hose from the filter to the pump with a clear plastic one so i could see the fuel come through.
After a couple of hand pumps it came straight through and connecting it all back togther she started first time.

So im guessing ive got an air leak in the hose although having switched back to original hose (clear plastic one looked like it wouldnt take the heat of the engine bay) she still works so the hole cant be that big or it would stop working again.

[Shaundon]

Update

Ok - i checked the pipe today by blocking it at the filter and blowing down the pipe at the pump(too scared to suck and get a mouth full of petrol!). Could blow quiete easily so must have an air leak somewhere. Am going to replace the pipe all the way back to filter from the pump but am wondering if i need the black nylon hard pipe or can i just run the rubber one all the way back? If i do then where can i get this nylon pipe?

Also blew the petrol back into the tank when the filter was disconected and it didnt dribble back down out of the tank after stoped blowing, ie went back into tank and stayed there!

Is this normal or do i have a blockage/air lock in the tank.?

S.

[Shaundon]

Further update - found the air leak, was the connection between the rubber pipe in the engine bay and the nylon hard pipe, tightened this up and no more air leak.

Still an issue that the petrol doesnt drain out of the tank after blowing back in, does if you start it draining with a suck but doesnt automatically. Not an air lock as opened the filler cap and still didnt come out. Strange....

[billy739]

make sure you dont squash the pipe by tightening the joint.

[Shaundon]

Checked and it looks ok - fuel seems to be coming through fine too.

Thanks for your help

S.

[djhammy]

Just to say I've got the exactly the same problem. It started last Monday so bought a new quality pump which works lovely when going but give it 20-30 minutes after stopping and hey presto no fuel getting to the pump it's all drained away. So need to find that air leak.

There's sometimes enough fuel between the pump and card to start it but drive a few yards and it conks out. Pump fuel up with a priming pump and it all goes fine again.

Drove from Southampton to Andover today with no problem after first getting the fuel up manually. When i got home I parked up outside Halfords after buying some hose clips when i drove off i managed to drive out of the car park and it stopped?? Ball starts all over again.

[kevtherev]

The push rod has to measure 100 mm
if its worn it will struggle to keep up

[djhammy]

HI kev replaced mine 18 months ago but that wouldn't explain the draining of fuel though would it?

[kevtherev]

No
I dont know why I posted that.. I think it was to another post

as to your problem
As I see it, theres a leak either in the pump or the line to allow the fuel to return
can you suck air through the inlet (with the pump empty)
or blow through it from the outlet

[djhammy]

Cheers kev i will try sucking the air through the pump in the morning. The pump is brand new i fitted it yesterday.

I first noticed it last Monday so replaced pump in case. It pumps fine when going.

Thanks again

Dave