disco 300tdi flat spot at 3000rpm

hi i have got a disco 300tdi n-reg it revs fine when stationary but when driving will not rev above 3000rpm in any gear (flat spot) i have serviced it but still same i have

replaced oil,oil filter,air filter,fuel filter cleaned sediment filter checked all hoses it runs clean and it has been blanked previous to me buying it and i am now stuck as to what else i can try any sugestions please

turbo hose de laminating or stuck waste gate or split intercooler are all possibles

is the waste gate the bar under the turbo
would i have to but a new hose
how do i check intercooler
sorry but i am a newby

just guessing the issue, but waste gate is activated by rod onto turbo if you pull a hose from turbo to inlet-should feel air pressure when reving it.
look for hose collapsing when reved-de laminating. any obvious splits in intercooler.

Others may have more suggestions,but these are common.

chears pipe stays the same when reving not run engine with pipe off but will do in a min and have to wait till light till i can check the other bits

i am getting presure from torbo pipes and it is expanding ok
how do i take waste gate bar off so i can check it
dont fancy taking intercooler apart untill i have checked the wast gate

Lift pump!

i have heard that it could be the lift pump but would like to check the waste gate as it was stood for a while before i got it and i have a feeling that it could be siezed
how do i check wastgate isnt siezed im not sure how to disconect bar

id rather change the IC AND the lift pump instead mate

sod playing with 300 act rods

thanks will let you know how i get on just ordered lift pump
what is the best way to block the top intercooler hose when flexy is removed as i am also thinking of resealing it just 1 thing less that it could be

d_ave2003 said:

hi i have got a disco 300tdi n-reg it revs fine when stationary but when driving will not rev above 3000rpm in any gear (flat spot) i have serviced it but still same i have

replaced oil,oil filter,air filter,fuel filter cleaned sediment filter checked all hoses it runs clean and it has been blanked previous to me buying it and i am now stuck as to what else i can try any sugestions please

Click to expand...

That's not a flat spot, a flat spot would suggest it then picks up again at higher revs, the techical term you are looking for here is "it won't go any bloody faster spot"!

I am ALMOST certain you will find it is the lift pump, it's first thing I would check especially on the 300tdi (since I have seen this on 300's about 5 times now) is the lift pump.

changed the lift pump now but no difrence its doing my head in now

How much diesel is the pump lifting from the tank? Disconnect the outlet side and pump it manually, it should squirt a LOAD of diesel out, no air or anything just pure diesel, if not then suspect an issue in the lines/pickup/fuel sedimenter corroded badly letting in a lot of air, which will reduce the volume of diesel it can pump.

If you get lots of good clean diesel then suspect an issue getting diesel to the injection pump, once you rule that out start thinking pump.

i have tred pumping manualy with blead screw open but i dont feel any resistance and nothing coming out .thought it might have something to do with engine lining up so flicked engine a little bit and tryed again still same and i have tryed flicking engine a couple of times but still no joy. it starts bit rough for a couple of seconds when i have removed fuel filter or sediment then runs great on tick over looked at sediment and it looks in good condition and replaced seal so no air through that .is there a nack to get lift pump to lift anything once i have sorted that bit i can check as you say above

Does it run ok once it's warm? I've noticed that mine won't do anything about 3000rpm until it been run for about 5 minutes... Trying to work out why!

no it dose it constantly and i cant seam to find sulution and dont want to take it to garage ill just get the usual ooo n a big bill for something stupit

Dave
My 300 TDi M reg would not reverse off my drive in a morning except when in LOW range.Then would not pull at all .speed had to be built up slowly .Also would not pull away at road junctions which was quite bad .
It would still travel at 70 mph and 3000 rpm on a straight road.
All cured by changing the Turbo discharge hoses and ensuring jublee clips were on correctly.cost was £20 for all hoses from Island 4x4
I had been chasing this problem for several months as i thought my hoses were all OK .
Are you sure yours are leak proof ?
Good luck .Will watch thread.

hi yes checked all hoses thoughly and i taken them all off today aswell as the intercooler and cleaned them all out in petrol got loads of muck out of them i also changed the pipe from fuel pump to turbo as when i was cleaning the old one i broke it (dough) well i know it definatly not blocked now i tryed it again and still the same i am 90% sure the wastgate is seized so i disconected it manifold bit moves ok but the rod wont move at all .what is the diaphram bit called at end of wastgate proper name please ill get a new 1 when i know what to look for thats if i can buy that bit seperate as the turbo its sefl seams fine

i have not checked thewastegate and it moves with resistance but as i understand it that is ok because it has a spring inside .i started it up today and it was reving to 4500rpm until it got warm then it started playing up again it wont rev above 3000rpm sometimes 2500rpm then it is like its being starved of fuel and when i hold gas at the point of it strugling the revs start to drop to aprox 2000rpm then it tries to rev up again but once it hits 2500 rpm it drops again when it starts playing up i get quite a lot of smoke from exhaust and manifold i have noticed a couple of nuts missing from manifold but it only blows at high revs i dont know if this would cause the problem but i am now going to get a new gasket just so that i can eliminate it .if anybody could help i would be very greatfull

Minw used to do that as well until I got rid of the egr valve now it goes much better!