p38a 2.5 diesel air in fuel system?

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oldskoolpro

Member
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Engine is in a 90 defender. The vehicle has been sat in a lock up for 6 months or so and started with no issues last time I was there. Now however, I can't get it to run on idle for long before it cuts out. It took about 20 starting attempts where it cut out after 3 seconds to get it tickover for 30 seconds or so but it was still running erratic, cuts out, and throttle seems to have very little effect on revs - tho that seems to improve the warmer the engine gets. Battery eventually ran out of juice, went back to it today with fresh charge and back to square one - fires up, then dies.

Any ideas? If it's a faulty somewhere in the fuel system where should I start bleeding from? The fuel filter on the bulkhead? How do I bleed if I can't hand crank?
Thanks guys
 
oldskoolpro said:
Engine is in a 90 defender. The vehicle has been sat in a lock up for 6 months or so and started with no issues last time I was there. Now however, I can't get it to run on idle for long before it cuts out. It took about 20 starting attempts where it cut out after 3 seconds to get it tickover for 30 seconds or so but it was still running erratic, cuts out, and throttle seems to have very little effect on revs - tho that seems to improve the warmer the engine gets. Battery eventually ran out of juice, went back to it today with fresh charge and back to square one - fires up, then dies.

Any ideas? If it's a faulty somewhere in the fuel system where should I start bleeding from? The fuel filter on the bulkhead? How do I bleed if I can't hand crank?
Thanks guys
Click to expand...
As it's been stood for 6 months bacterial growth in the fuel is a possibility, drop the filter and look for black slime. A faulty lift pump is another possibility.
 
oldskoolpro said:
Engine is in a 90 defender. The vehicle has been sat in a lock up for 6 months or so and started with no issues last time I was there. Now however, I can't get it to run on idle for long before it cuts out. It took about 20 starting attempts where it cut out after 3 seconds to get it tickover for 30 seconds or so but it was still running erratic, cuts out, and throttle seems to have very little effect on revs - tho that seems to improve the warmer the engine gets. Battery eventually ran out of juice, went back to it today with fresh charge and back to square one - fires up, then dies.

Any ideas? If it's a faulty somewhere in the fuel system where should I start bleeding from? The fuel filter on the bulkhead? How do I bleed if I can't hand crank?
Thanks guys
Click to expand...

Lift pump should push the fuel up. If you look in the Technical Archive it will have a post telling you how much to expect in 30 seconds. Leak off pipes are famous for failing. Crack off injectors until fuel comes through but mind yourself as it may try to start and you don't want anything dropping down the inlet with the manifold off.
 
There should be a clear pipe after fuel filter - any bubbles in it? You need to eliminate nearly all the air

Spill pipes are a favourite cheap too, you will have to crack the injectors and crank engine till fuel comes through if it's full of air.

They have probably fitted an inline pump somewhere - could be shot. If they have used P38 in tank pump they let air in when under 1/4 tank if they are dodgy
Also check filter and water drain on filter bottom is not loose letting air in

I've never seen an M51 engine in defender? Any chance of some pics - that's like super porn :)
 
RangeRoller dt said:
There should be a clear pipe after fuel filter - any bubbles in it? You need to eliminate nearly all the air

Spill pipes are a favourite cheap too, you will have to crack the injectors and crank engine till fuel comes through if it's full of air.

They have probably fitted an inline pump somewhere - could be shot. If they have used P38 in tank pump they let air in when under 1/4 tank if they are dodgy
Also check filter and water drain on filter bottom is not loose letting air in

I've never seen an M51 engine in defender? Any chance of some pics - that's like super porn :)
Click to expand...

P38 in tank pump cannot leak air if the tank has fuel in, it is not possible.
 
wammers said:
P38 in tank pump cannot leak air if the tank has fuel in, it is not possible.
Click to expand...

If my tank goes low (1/8th maybe) I get bubbles? Always presumed it was something to do with pump as it’s fine if there’s plenty fuel in there? Not run it down since and I’m not going to tempt fate on that one ;) no hissing when I open filler cap either.

OP - take Wammers word on it, I do :). He’s never led me astray
 
RangeRoller dt said:
If my tank goes low (1/8th maybe) I get bubbles? Always presumed it was something to do with pump as it’s fine if there’s plenty fuel in there? Not run it down since and I’m not going to tempt fate on that one ;) no hissing when I open filler cap either.

OP - take Wammers word on it, I do :). He’s never led me astray
Click to expand...

If the lift pump fails air can be drawn in by the injection pump high pressure pump sucking fuel out of the tank. Any discrepancies in piping may leak air. O'rings on filter for instance. But the lift pump itself can't introduce air. The pump and pickup are at the bottom of the tank standing in fuel. Fuel is under pressure from lift pump so fuel can leak out of a joint or pipe but air cannot leak in. At least not whilst the pump is running. :);)
 
Thanks guys, havent had chance to take a look yet but will keep you posted.
It's for sale btw..I'll post the deets in the landys for sale forum
 
as mentioned by others 50posts is not too hard. Pop into intro section now and then, find a thread with 0replys after 3days and just say hi, paste something they can’t find or don’t know about plenty get lost at first. My favourite - do something with your Landy then post it in WDYDWYRRT now and again. (Pics or it didn’t happen :cool: before and after is great) Everybody picks and tells you how crap a job you did - it’s great fun :D:)

Maybe that’s just me....:p
 
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