zinnemann

Member
Hi all, I have a problem that is vexing me.

My manual Disco 200tdi (92k miles) will only start on the second turn of the key and when I get to junctions it wants to stall. I can prevent this by quickly applying some gas in neutral.

I have cleaned the air filter and replaced the following but it has not solved the problem:
  • leak off pipes
  • glow plugs
  • glow plug relay (I now have a perfectly good used one spare if someone wants it)
  • fuel filter (used the pour clean diesel into it method as primer handle in wrong cam position)
What would be the next thing for me to check? I am guessing it is a fuel issue so could it be a faulty diesel lift pump? Is it more likely to be the main injector fuel pump? Could it be air trapped in the fuel line caused by me replacing the filter?

Many thanks in advance for any help.
 
Based on my experiences with a 300, and thinking they might be similar ... I'd check the Water trap (Sedimenter / filter) somewhere near the offside wheel arch front. I'd also check the fuel pipe connections at the petrol tank. The nylon that the pipes fit into are known to split and allow air ingress. Get at it by opening the round flap under the boot carpets. Sorry if this is a red herring ...
 
Thank you Paul. That is very helpful. I want to check everything possible because at the very least I will learn a bit more :) I was not aware of either of those potential causes so will investigate them with vigour.

I am also open to any suggestions from other members.
 
Thanks Magic. I will check the level in the fuel filter tomorrow.

Regarding the sedimenter should I replace the O rings on it when reassembling it?
 
Many thanks Magic and Paul.

I have done the following:
  • Cleaned out sedimenter
  • Replaced diesel lift pump
Cleaning out the sedimenter made the exhaust gasses much less black but neither of these has given my disco any more power. It still does not want to go past 1,500 revs.

I have removed the cover above the fuel tank and can see the top of the sender unit with a black locking ring holding it down.

The pipes between the top of the sender and the fuel pipes are metal. Is this different from the nylon fittings that can split? I checked my Haynes manual (page 4A.7) and can see that the top of the sender there is nylon. Mine is not like that, it is metal. Do you think I have an aftermarket unit (loads of my disco is modified)?

There is a small wire that is not connected to anything.What is this and should it be soldered to the metal lug on the top of the sender unit?
 
The symptoms you describe are exactly what I had with my old 200tdi a few years back and I solved it very easily by pumping huge amounts of sealant around the area where the two metal fuel pipes entered the white plastic housing on the sender unit, where cracks were starting to appear. Not the most professional way to do it but it was one of those "that will do until I get around to doing it properly" situations, I fully intended to replace the sender unit and fuel pipes but never got around to it as it just kept on going with no further problems
 
Yes, I put on a new fuel filter a few weeks (and zero miles) before I replaced the lift pump but I have not put on a new filter since I replaced the lift pump.
 
There is almost no fuel in the fuel filter. If you ask a fourth time I suspect there will still be almost no fuel in the fuel filter.
 
PMSL ! AIR LEAK AT TANK to start with then at sedi filter ! get some tiger seal for pipes at tank & go fromthere !
 

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