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Lift Pump


Frax

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Well started my 300tdi the other day after it had been sitting for months, it was a bit of a pig to get going, fuel tank had been out and timing belt was fitted + all new filters. I tried to get fuel up to the injectors using the lift pump but there did not seam to be any back pressure in the pump so used a vac (brake bleed thing) to suck fuel through the filter and she started and run.

I have had this happen before and I thing it depends where the pump sits on the cam as to if it will pump or not.

A bit lumpy to start with and loads of white smoke.

She did seam to settle out and the smoke cleared - it was just left ticking over & never driven.

Went out today and tried to start it again - did not want to go but did eventual, still no pressure felt when operating the lift pump by hand.

Is my lift pump goosed or could it be something else.

Regards

Frax

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Thank you the reply, I did not think a pin hole in the return line would make any deference to starting as long as there is fuel to the supply but not sure.

I did think I may have a pin hole in the pump diaphragm as this would pull air and may also let it run - though not well.

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Air in the return lines from the injectors (leak-off lines I call them) will definitely cause starting issues. Both my 200Tdis suffer from it. On the 90, the banjo bolts work loose about once every 12-18 months, the only symptom is an extended cranking time in the morning after sitting all night. Fine the rest of the day. Nipping up the bolts sorts the issue perfectly :)

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I would turn it over but it has been running twice so cam position must have changed, lift pump pressure has stayed the same.

I have a vintage tractor with a similar style pump and only once in three years has it ever stopped in a position where I could feel no pressure at the pump.

Have you ever tried your one and do you feel pressure on the plunger leaver when pushing it down.

I am presuming that it should be similar to the old tractor.

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I know when I changed the fuel filter last time I had to turn the engine over before I could get the pump to fill the filter and I remember feeling a difference then.

I just went outside to have a feel of my one to refresh the memory (oo-er) and in all honesty it didn't feel to have much back pressure (could easily be mistaken for none tbh) so I started and stopped the engine again and the pressure still felt the same. I'm fairly certain that it was really floppy when stuck on the cam though.....

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I was just thinking that if I remove the bleed screw on the fuel filter and then pump I should be able to see if there is pressure there.

Thank you for going out and having a look, my one used to start 1st turn before I started my rebuild. Going to order a pump anyway.

I don't know what pressure it should put out but I would it would be 60psi+ at the injectors.

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Easy way to fill the filter - take the wire off the fuel stop solenoid, open the bleed screw and crank the engine on the key until fuel comes out of the bleed screw, stop cranking, tighten screw, replace wire. Job done. :)

The lift pump will only get fuel as far as the injection pump, you may well need to crack off the union on the injector to get any air out and fill the system as far as the injectors.

HTH

Mo

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Hi Mo

I did bleed the whole system through to the injectors and it ran OK once hot the first time but after it stood for a day did not want to start.

New fuel pump is on it way and I think I will change the bleed off flexies just in case air is getting in and the fuel is running back.

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  • 2 weeks later...

Well just home and I have fitted the new lift pump which has got pressure on the manual lever. Started first time but lots of white smoke and not great throttle response. The smoke does clear but still seams a bit slow at responding to the throttle. Temperature gauge is not reading for some reason (td5 dash with green sender). I was reading about 60deg at the thermostat housing.

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