Athena Posted October 23, 2009 Share Posted October 23, 2009 HI All My Landie is a 90, 1987 2.5td Help please, I have just completed a trip to york from sheffield (uk) on the M1, running in 5th at 60mph when going up hill i slow down it was always at a steady rate as the hill gets steaper, however tonight my landie felt almost as if i was braking for a second at the same time as accelerating? and then in stead of speeding up going down the hill, it would still have this slowing effect, i drop to 4th speed up, next hill same thing? at low speed 30/40 no apparant problem, any ideas people thanks everyone for your help as i know i will get loads of it! Cheers Dan Quote Link to comment Share on other sites More sharing options...
RILEY Posted October 23, 2009 Share Posted October 23, 2009 fuel lines and filters good luck hope thats the ting Quote Link to comment Share on other sites More sharing options...
poohbear Posted October 23, 2009 Share Posted October 23, 2009 as above, plus check lift pump is working OK. HTH. Dave. Quote Link to comment Share on other sites More sharing options...
errol209 Posted October 25, 2009 Share Posted October 25, 2009 as above, plus check lift pump is working OK. HTH. Dave. And the boost diaphragm in the injection pump (there's a guide in the technical forum. Costs about £10 and takes 30 minutes to do. Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 25, 2009 Share Posted October 25, 2009 And the boost diaphragm in the injection pump (there's a guide in the technical forum. Costs about £10 and takes 30 minutes to do. Isnt the fuel tank pressurising a sign of this? Quote Link to comment Share on other sites More sharing options...
errol209 Posted October 25, 2009 Share Posted October 25, 2009 Isnt the fuel tank pressurising a sign of this? That too, I was just going to say it Quote Link to comment Share on other sites More sharing options...
Athena Posted October 26, 2009 Author Share Posted October 26, 2009 That too, I was just going to say it Hi all Thanks for all the help, I have changed my fuel filter, but still have the problem, DOH, checked fuel lines seem to be ok.... but what is the connection between fuel tank and the diaphragm in the fuel injecter pump? i have also heared there could a be secondary fuel sedimenter unit, between fuel tank and fuel filter.... but not all denfenders have them, i know i said this before but i don't understand why i am getting this problem at 60mph but when driving around town or even between towns no woriies, just seems to be on the motorways, as soon as i hit 60mph trouble Cheers Dan Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 26, 2009 Share Posted October 26, 2009 My theory is that pressure build up in the tank creates a blockage effectivley on the tank retur. Once this builds up enough, it blocks back as far as the injectors and impedes the pump and suply to the pump effectivley starving the engine of fuel. At low speeds, fuel demand is lower and it can be coped with (possibly without noticeable lack of perfomance). I had it on my old TD - i tool the fuel cap apart and made sure the breather was working ok so the tank didnt pressurise. That was before the days i joined the forum and learned that a split fuel pump diaphragm would allow air into the system to pressurise the tank. The diaphragm on my engine should have been changed probably, but i changed the engine instead! (it was knackered anyway) Quote Link to comment Share on other sites More sharing options...
Les Henson Posted October 27, 2009 Share Posted October 27, 2009 If the tank isn't pressurising, then it's not the boost diaphragm. I would look at the lift pump, failure of it reduces higher revs/top speed. Les. Quote Link to comment Share on other sites More sharing options...
reb78 Posted October 27, 2009 Share Posted October 27, 2009 Yep. I got hung up on answering the bit about the boost diaphragm. For 25.00 if you've done all the easy checks, the lift pump would be the next place i'd look. Then when you discover the TD needs to be swapped for a tdi, you have a spare new lift pump for it! Quote Link to comment Share on other sites More sharing options...
Athena Posted October 27, 2009 Author Share Posted October 27, 2009 Fantastic lads thanks for the help! i will work on all these ideas this weekend and let you know how i get on, cheers Dan Quote Link to comment Share on other sites More sharing options...
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