Engine not cranking after service...

So picked up the 90 from Mark @ LRS after its full service etc, car was a little lumpy to start Mark said it could be a bit of air in the fuel filter from the service, gave it some accelerator pedal and off we go, drive home the engine felt as good as it ever was, everything felt nice and tight.

Later yesterday evening tried to it start again and the engine is turning but not catching..... glow plugs have been changed, battery is holding charge etc, finally after about 6/7 turns it finally caught - I thought must be more air in the system?

Tried her again this morning and the engine wont catch, feels like the fuel is the issue as the battery seems okay (currently on trickle charge) , plugs have been swapped, starter is fine etc

Ive opened the bleed screw on the fuel filter and no air is coming out or bubbles, tried the lever on the lift pump and it feels quite slack.
Finally got the engine turning over but I need to give pump the accelerator a few times whilst turning and it will catch, so feels like its a fuel issue to me?

Took it out for a spin and the engine is driving fine and getting upto speed, no stalling or lack of power issues.

Never had this problem until after the service?

Which engine do you have?

Kev12 said:

Which engine do you have?

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Sorry, 300 tdi

First thing I would try would be checking for fuel at the injectors, if none there then work backwards. Lift pumps should be considered almost a service item, if the lever feels like its doing nothing try turning the engine over a bit by hand

It was ok before service ? Take it back there then. Likely a fuel filter issue as it was disturbed or lift pump if disturbed. Lift pump not working by hand can be it just happens to be on the cam. Turn engine a bit it should work.

tottot said:

It was ok before service ? Take it back there then.

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Yeh was fine - Ive spoke to Mark at LRS who said to bring it back Monday and he can check it over, just wanted to check if there was anything simple I could check? Before it went into service the engine was struggling to start due to bad glow plugs, so I used some easy start on the plenum, then I noticed the hose was not tight on the plenum inlet - could I have an air issue?

The engine will start with the top-intercooler hose disconnected, it won't go very well as there is no turbo pressure but start/tickover is fine.
The lift pump (as indicated) will only work if it is off the cam to acheive that you need to turn the engine over slightly.
If that's nacked a Delphi replacement is the one to go for ERR5957G

The 300tdi engine will start without a lift pump but can be a struggle as the FiP needs a good head to pump efficiently (ie no air).
It's messy but if you disconnent the fuel solenoid you can turn the engine over and bleed the filter by loosening the bleedscrew which will confirm the pumps operation.

Just a note the lift pump lever is not giving any resistance when Im pumping it with the engine off and on.
Could the diaphragm be faulty inside?
Still not sure why it needs the accelerator down to start though??

Well you would not feel the lift pump doing any thing with the engine is running as the engine is doing the work. Having turned the engine over pump is likely off the cam, give it another go with fuel filter bleeder open.

tottot said:

Well you would not feel the lift pump doing any thing with the engine is running as the engine is doing the work. Having turned the engine over pump is likely off the cam, give it another go with fuel filter bleeder open.

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Ahh I see, I'll give it another go later.. so if pump has no resistance - turn engine to get on cam - the open fuel filter bleed screw and try the lever to pump again, Im guessing fuel should start come out the bleed screw no bubbles/froth.

The lift pump will not work by hand if its lever is ON the cam. It will be OFF the cam for most of the rotation of the shaft, it is just pot luck it can stop on the cam.
If for some reason it has been replaced it is possible the lift pump lever can be fitted the wrong side of the cam and will not work which is why I ask if it has been disturbed/replaced.

Thanks @tottot - Ive just got it started again - Opened the bleed screw and pumped the lever - still nothing coming out.
Im leaving the lever at its high position also.
Tried the engine again and it had a very rough idle and died, turned over again with accelerator and started again but very rough idle - I did leave the bleed nut open so tightened that up and started engine again running fine - when I kill the engine I can hear the fuel draining back from around the fuel pump, it does have a slow sucking sound but I guess this is the system self bleeding?

Air should not be getting back into the system, the self bleed is part of the injection pumps internal system. Most likely your problem is at the filter or lift pump allowing air in and causing fuel to run back to tank. You may think to see a fuel leek when engine running but it will be so small as to be hardly noticeable.

Possibly a bad fuel filter then? Allowing a small amount of air in.
The fuels not coming out at all on idle or with some revs when I leave the bleed nut open to try and help bleed it, no bubbles or fuel at all.
Can only think its the filter or lift pump, but not sure why the lift pump would just go after a service, its not been touched?

karlp606 said:

Still not sure why it needs the accelerator down to start though??

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You don't .....

karlp606 said:

Thanks @tottot - Ive just got it started again - Opened the bleed screw and pumped the lever - still nothing coming out.

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It does sound fuel related, my 300tdi starts very easily (especially when warm) and I have had a similar issue to you in the past, which did turn out to be the fuel lift pump.
The spring had broken on mine, which I proved by turning the engine over and opening the bleed screw.
With a new lift pump, diesel pulses out with just 1/8 of a turn of the bleed screw.

karlp606 said:

<snip> Can only think its the filter or lift pump, but not sure why the lift pump would just go after a service, its not been touched?

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Once. when fitting a new fuel filter and using the lift pump to fill the filter and bleed, I broke the diaphram by getting to aggressive with the lever.

Would be unlucky if lift pump went same time as service but you never know, Puts the filter as number 1 suspect.

Could possibly be just bad timing and the fuel lift pump has gone at the same time then?
The lever is quite slack and Ive left it in the up position when the engine finally cranks and its running great.
But still no fuel spurting through with the bleed screw open so low pressure on the fuel pump then?

@tottot That's what Im thinking - strange timing!

Just seen a Britannica Restoration video with a 300 tdi same issues as mine - no fuel coming out the bleed screw when the engine is running/revving so he took the fuel cap off and that helped pressurise the fuel system and out came the air bubbles of the fuel filter bleed screw.
Worth a try? If that fails I'm guessing must be a bad fuel filter.. nothing else it could be!