Sudden loss of power

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Peter Mann

Peter Mann

Member
Posts
18
Location
wimborne Dorset UK
I have a L reg Defender tdi 300. A strange thing happened yesterday and I explain in order.

  1. Refuelled at local Shell garage.

  2. Drove car for 200 yards and had to stop facing up a slight hill to let truck pass me.

  3. Pulled away for 10 yards and suddenly no power. Idle was ok though but a bit slower than normal. Foot to the floor and absolutely no revs at all.

  4. Turned engine off and had a quick look around engine bay but nothing obvious.

  5. Turned engine on, opened bonnet again and manually moved linkages. Again no revs at all and again slower than unusual idle (almost stalling).
  6. Undid petrol cap in case there was some kind of vacuum. No improvement.

  7. Fortunately I was only 50 yards from home and crawled home using low ratio and motor on idle

  8. Had lunch. Came out and motor started and revved as it should have done and no problem. Went round the block...no problem. Next day did a four mile run. No problem at all. Whats going on?

  9. Opened vent underneath fuel filter and no water or crud.

  10. Emptied some fuel out of tank and again no water or crud (I will admit though the flow was limited and any dirt in there would not have flushed out easily)
Any gut feelings gentlemen? Is it dirt or something else? Or can someone give me a logical process to follow.
I would be grateful
Peter
 
My guess would be you have disturbed some gunk in the fuel tank when filling up, and it blocked the fuel pickup. After sitting for a while, it settled back down to the bottom of the tank. If you have the means, it might be worth removing the pickup/sender unit and having a look into the tank (assuming underseat tank). Or you might try draining the tank and seeing what comes out with the fuel.
 
Sounds like lack of fuel so presuming that the fuel filter has been changed regularly, I would suspect the fuel lift pump is on it's way out. Cheap to replace at around £30 for the part but make sure it's a Delphi one or you will be doing the job again in a few weeks.
 
Thanks for replies so far. I have now opened up the tank and it looked clean to me. No crud in the metal pick up pipe either but of course they may be crud in the plastic(?) pipe from then on.
How can I check that the fuel pump is on its way out?
 
If you disconnect the fuel outlet, you should get a good blast of fuel when operating the manual lever (make sure it's on cam). The injection pump will pull fuel through on it's own when the lift pump fails which will provide ample fuel for idle which is why I think it's suspect.
 
sp00k said:
If you disconnect the fuel outlet, you should get a good blast of fuel when operating the manual lever (make sure it's on cam). The injection pump will pull fuel through on it's own when the lift pump fails which will provide ample fuel for idle which is why I think it's suspect.
Click to expand...
Brilliant..thanks..I will try this. But why is working again OK now? surely a defective pump will stay defective? To remind you.The landy has been running now for two short trips with no problem ??
 
It won't show any problems until there is not enough diesel going through for demand. When mine went, it was very obvious as diesel was ****ing out of of it down the side of the engine but there was still enough fuel to drive normally! The early indications of a problem would be issues driving up hill and under full load (towing etc).
.
If your not sure, I would get one anyway and keep it in the back for when it does fail completely. If it's the lift pump, it can only get worse and fail. If it's not, you will have a spare which you will need one day in any case :)
 
It may be worth having a look at the fuel filter, to see if you have pulled some crud through. Never does any harm to change them, and they're cheap enough.
 
Even if lift pump is totally dead the engine should still rev, Ive had a few die on me and they drive pretty much the same but lose top end power, the bosch injector pump has it's own internal lift pump and in many car applications it's all they use to supply fuel.
 
Hi. Thanks for advice so far. I had lift pump and filter replaced. All the lines blown through and yesterday landy ran perfectly for 20 miles. Today..started normally, ran for 300 yards and suddenly again no power and very slow idle and in fact stalled. (lots of foul language here) WHAT is going on? Need help here lads..can anyone have a stab at what else could it be?
Landy as of ten minutes ago will not start.
One thing that came to mind as I was walking home is a the bit that shuts the engine down. Could that action all by itself???
Peter
 
Easy to eliminate that, put 12v to it and try again. Tbh blowing lines and changing filter is a waste of time if you can't/haven't drsined and flushed the tank.
 
Discokids said:
Easy to eliminate that, put 12v to it and try again. Tbh blowing lines and changing filter is a waste of time if you can't/haven't drsined and flushed the tank.
Click to expand...
Thanks. Do you STILL think its fuel starvation?. I did inspect tank through top hatch when all this started a week ago and it looked clean. I also drained off a litre or so and no dirt. I will do the 12v to stop valve as you say.
 
One thing I forgot to mention which may be relevant. The car has a fancy alarm and immobilizer system. The car was an ex emergency vehicle of some kind (maybe RNLI) and obviously had lots of devices fitted. The immobilizer always cuts in 20 seconds after ignition is switched off. Has anyone had a problem with immobilizers playing up and causing apparent fuel starvation?
 
An immobilizer will usually cut the fuel off completely - you would have not just a power drop, but total loss/engine stop. Has the problem happened again since? You may have flushed any gunk through the system by now.
 
I done some more work and the supply of clean fuel to the (new) fuel filter is guaranteed good. So now may I ask for advice on removing injector(s) checking them etc and the pump itself. Is it difficult? Will a set of spanners and socket set etc suffice or will I need special tools. Landy now will not start at all by the way.
 
try it with fuel cap removed, undo front banjo on injection pump and work lift pump it should pour out , remove solenoid plunger and refit solenoid (it will need stalling to stop engine after) remove injector pipes and turn engine over each delivery outlet should squirt an equal solid burst , a clear pipe in between filter and front banjo on pump will show if air is entering , id suspect pump before injectors
 
jamesmartin said:
try it with fuel cap removed, undo front banjo on injection pump and work lift pump it should pour out , remove solenoid plunger and refit solenoid (it will need stalling to stop engine after) remove injector pipes and turn engine over each delivery outlet should squirt an equal solid burst , a clear pipe in between filter and front banjo on pump will show if air is entering , id suspect pump before injectors
Click to expand...
Thank you James
Today I removed both low pressure pipes from lift pump and also low pressure from filter to main injector pump. Blew them all out and no dirt. Refitted and engine started first time DESPITE all the air I left in the pipes (strange that?) It was still running perfectly five minutes later.
I am a bit nervous of undoing the injector pipes them selves. Apart from keeping dirt out, is it just a question of unscrewing them out and observing squirts on turning engine over?
 
I did ask my garage when it all started but they just shrugged their shoulders. Anyway today I have just replaced all the fuel from another garage. Drove off and again car lost power after about 30 secs driving. Sat there for four minutes, started car and car went well for about 50 yards then died again but still some idle. Did this again and again and every time after 50 yards she dies. There is a pattern here and it should tell someone what to look for. Help!

Ps. Is air getting in somewhere perhaps but how do I find it?
 
Solved ( I hope) The car came with a fuel stop valve on top of tank. I went to check if air was getting in there. Removed the pipes and then said.."Sod it"..lets remove the whole lot just leaving as it would have left the factory. All my problems instantly went away and on top of that the car is noticeably faster.
I checked the discarded fuel tap and piping and could find no leaks at all. So what happened? Air locks come to mind but she is going like a bomb so I finish this post here. Thanks everyone.
 
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