Orgasmic Farmer Posted December 14, 2006 Share Posted December 14, 2006 Got the £500 Disco mot'd no probs but noticed the other day when cold that under acceleration it would hit about 3000 rpm then die. Just for a brief second. And then off to go again. When warm it didn't seem to happen. Then tonite I took it on a motorway and and it did it once just as I was accelerating up to 70. Then was great again. It has covered 150 miles since I refitted the fuel tank after chaning the boot floor. Finally tonite, coming up the farm drive which is very rough it died completely but did not cut out. I held my foot on the floor and left it there and it would slowly rev to 2000, no more and then drop back to about 400 rpm. Then it would rev back up to 2000 and back down to 400. I timed it, it was about a 5 second cycle. All the time my foot was on the floor. The drive is quite steep so I put it in low first and managed to limp up to the house, slipping the clutch to avaoid stalling as the engine died each time. My suspiscions are either a. there is dirt in the line from having had the tank out and shake it all up b. the fuel filter or sedimentor (or both) are blocked and need changing/cleaning c. the lift pump has gone weak. But none of the symptoms really points to any one of them conclusively I would appreciate any help solving this before I start swapping thing over from the other disco Cheers Mark Quote Link to comment Share on other sites More sharing options...
reads90 Posted December 14, 2006 Share Posted December 14, 2006 Got the £500 Disco mot'd no probs but noticed the other day when cold that under acceleration it would hit about 300 rpm then die. Just for a brief second. And then off to go again. When warm it didn't seem to happen. Then tonite I took it on a motorway and and it did it once just as I was accelerating up to 70. Then was great again. It has covered 150 miles since I refitted the fuel tank after chaning the boot floor. Finally tonite, coming up the farm drive which is very rough it died completely but did not cut out. I held my foot on the floor and left it there and it would slowly rev to 2000, no more and then drop back to about 400 rpm. Then it would rev back up to 2000 and back down to 400. I timed it, it was about a 5 second cycle. All the time my foot was on the floor. The drive is quite steep so I put it in low first and managed to limp up to the house, slipping the clutch to avaoid stalling as the engine died each time. My suspiscions are either a. there is dirt in the line from having had the tank out and shake it all up b. the fuel filter or sedimentor (or both) are blocked and need changing/cleaning c. the lift pump has gone weak. But none of the symptoms really points to any one of them conclusively I would appreciate any help solving this before I start swapping thing over from the other disco Cheers Mark I would say to check feul staveing. Maybe a kinked pipe or traped pipe. Even more so after you have \refitted the tank. May be a split in the fuel pipe which is letting in air. There is not alot that will not keep a tdi running. But remeber the Tdi is a self bleeding engine so unlike earler diesels if it loses fuel it will still bleed its self when it gets fuel. Other thing to check is the spade conector on the top of the fuel pump. Sometimes get rusty and have a dodgy conection. The other thing to check is that the air filter is not dirty or blocked and its not a lack of air that is causing the probelm., Had this with a V8 but had the same problems that you have with the Tdi Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted December 14, 2006 Author Share Posted December 14, 2006 Thanks for the reply, the plot thickens Just had a look. Opened bottom of fuel filter. Nothing! Eventually by removing the bleed screw and the drain completely I got some water and gungey crud to flow out. NO diesel at all. I cranked the motor (which started) and nothing came out of the filter at all. I disconnected the lift pump (which feels like a limp lettuce) and cranked it again. It runs like it did last night and I left it ticking over for about 5 minutes. Now something is wrong here. How can it be running at all with a completely disconnected fuel pump? I guess the injector pump itself is somehow drawing a small amount of fuel via the return line (is this how the tdi self bleeds?) but not enough to run properly. I will swap the lift pump from the other engine and see if that cures it. The crud in the filter makes me think that the pump has failed through having to work hard to clear the lines following tank removal. Does that make sense? Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted December 14, 2006 Share Posted December 14, 2006 Lift pump!! been there, done that, it was running a bit weird, then wouldn't rise above 2k rpm without falling back to almost stalling, and wouldn't drive anywhere unless in low box. this happened on a roundabout!!! At idle, it appears the injector pump can just about suck from the tank, once you've give it some revs, the injector pump just can't suck enough fuel through. To test, fill the fuel filter by hand, on the outside, and run the engine up. undo and remove the drain plug and hold a finger to the hole, i bet you'll feel it sucking on your finger. here's how i got home.... Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted December 14, 2006 Author Share Posted December 14, 2006 cheers for the reply luke. Definately confirms it then. When I undid the drain plug on the filter it did appear to suck like a vacuum was there. I only disconnected the line from the lift pump to the filter and then ran the engine. I know from bleeding tractors how much mess this should make. But nothing. Not a sausage. Bone dry. Will swap the pump from other engine for now and get a new one in town thanks for replies Mark Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted December 14, 2006 Author Share Posted December 14, 2006 ps - great way to gauge your fuel consumption there mate Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted December 14, 2006 Share Posted December 14, 2006 thinking it through, i suppose it could be a blockage between the pick-up and the lift pump, I disconnected the inlet to the lift pump and sucked some fuel through to check the pipe. easy to check, since you're about to pull the lift pump out anyway, and just might be the reason. My money's still on the lift pump though. Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted December 14, 2006 Author Share Posted December 14, 2006 just the feel of of the lift pump tells me it is knacked. But I am kind of thinking it is broken for a reason. Though I know they are vunerable and more or less service items from what I have heard. Still at £13 perhaps I will just replace and see how long it lasts. Quote Link to comment Share on other sites More sharing options...
white90 Posted December 14, 2006 Share Posted December 14, 2006 the pump lever only has any feel when it is on the cam lobe bet it is knackered though the diaphragm parted from the shaft on mine. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted December 14, 2006 Share Posted December 14, 2006 If its over 120k miles...its the lift pump. They all seem to give up around then. The injection pump has quite a large (0.4l??) gallery which will keep it running when there is no fuel. On old landy engines with lucas injection pumps, the fuel is used as hydraulic fluid to transfer forces within the pump...so if you run out of fuel in these, you are buggered. The Bosch fitted to the TDi is near bullet proof...and hence will self bleed. The injection pump iteslf will has a mega powerful suck (??!!). Anyone who has got a blocked fuel filter will know that it will suck air through the joints. I do not have a lift pump on my secondary tank fitted in the back of my Disco...the injection pump pulls the fuel through fine. Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted December 14, 2006 Author Share Posted December 14, 2006 Well the lift pump was definately gone. The plunger was disconected from the end of the lever. Fitted one off old disco and its good as new! Engine has done 175K and old one 150K so I expect to have to fit a new one soon. HOWEVER...... I was unable to suck fuel through the lines and unable to blow back to the tank either. So i used the air line and gave it a blow and there was a bit of opposition then off it went and it blew through to the tank no probs. So I am still thinking there is ****e in the tank and that it will get into the lines again at some point probably causing pump failure once more! Ah well we will see. I had this problem on my Massey Ferguson and it took almost 2 years before I finally managed to fix it completely! Thanks for all advice and help Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted December 14, 2006 Share Posted December 14, 2006 missed your comment about fuel consumption earlier. It was interesting!!! it's the only time i will ever drive with the fuel gauge going UP! obviously the fuel return was still going to the main tank, by the time i'd got home (less than 15 miles away) , i'd put about 20 Litres into the cereal box!!! the gauge had gone up considerably. Quote Link to comment Share on other sites More sharing options...
Andy Posted December 14, 2006 Share Posted December 14, 2006 how bad was the tank Mark? the metal pipes on the top rot & let air in, sounds like you've found the fault but worth checking if your the area. ive had the pickup tank in the tank fill with crud, easy to sort by just removing the sender unit. nice to hear its alive though. Quote Link to comment Share on other sites More sharing options...
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