New Disco, and a hesitation problem at higher RPM and under high load

tombardier · Nov 16, 2012

I've just swapped my old shed of a 90 for a tidy Jap import 300TDI auto Disco, so I'll be hanging around in here a bit more

Got a couple of little problems to iron out, but I'll just list the one in this thread. It's basically most prominent when I'm flooring the pedal up steepish hills, going at 60mph or so. There is a bit of hesitation where I'll get to about 3300, suddenly the RPM drops to 3000 for a couple of seconds, then it's back up to 3300, and back down etc etc. I'm not that used to the autobox, so at first, I thought it might be a problem with the box, because of course in a manual, I would have felt a lot more of a lurch with the engine RPM being directly related to the wheel speed, but I've come around to thinking that it's definitely an engine problem.

So my list of things to check this weekend so far are:

turbo/intercooler hoses
vacuum pipe that apparently leads to the injection pump - not entirely sure of this one
fuel filter, sedimenter

It's been de'egr'd and de-cat'ed, and generally, I'm very happy with how torquey it feels, so my suspicion is that it's something to do with the turbo hoses, but I'd appreciate it if anyone had any more suggestions on things to check tomorrow

Cheers!

RichP · Nov 17, 2012

My autobox (200Tdi) does that when revs are around 2500, doesn't seem to know what gear it should be in. It's been like it since I bought it and I've just learned to put up with it as there's no problem otherwise.

tombardier · Nov 17, 2012

I definitely don't want to put up with it

I swapped all of the intercooler fittings for silicon ones today. I've managed to floor it up hills today with no problems in places where I was consistently getting the problem before! It's too early to say but I'm hopeful!

crazymac · Nov 17, 2012

If it does it again change the lift pump!

Tomp · Nov 19, 2012

sounds like a fueling problem.....
also have you checked if the small plastic pipe is connected to the turbo

tombardier · Nov 19, 2012

It did it again most convincingly yesterday. I think I'll check this pipe before changing lift pump, although they're cheap as chips

there's another chap that's posted the same problem but assumed it's an autobox issue. See here

http://www.landyzone.co.uk/lz/f8/auto-gearbox-problem-198782.html

tombardier · Nov 19, 2012

http://www.landyzone.co.uk/lz/f8/auto-gearbox-problem-198782.html

the saga continues here, and it sounds like it could be the torque converter locking and unlocking?

thebiglad · Nov 19, 2012

tombardier said:
http://www.landyzone.co.uk/lz/f8/auto-gearbox-problem-198782.html

the saga continues here, and it sounds like it could be the torque converter locking and unlocking?

If you are driving a std correctly running TDi 300 auto at speeds above 52mph and then you floor it, 2 things will happen:

1. You will come out of TC lock-up &

2. If you have pressed the accelerator enough you will drop a gear.

Both of these will impact on revs and drive.

tombardier · Nov 19, 2012

aye of course, but to keep on unlocking, then locking, then unlocking, and locking again and again all the way up a hill whilst you're trying to overtake someone is a bit frustrating

thebiglad · Nov 19, 2012

tombardier said:
aye of course, but to keep on unlocking, then locking, then unlocking, and locking again and again all the way up a hill whilst you're trying to overtake someone is a bit frustrating

Yes it can be frustrating but you learn with time how to get the best from these autos. Experiment a bit using different pedal pressure to see how the gearbox reacts.

Also remember:

Weight: 2200kgs

Power: 111 or 120 bhp

Drivetrain: Permanent four wheel drive

The above is not a recipe for a 'ball of fire' vehicle

tombardier · Nov 19, 2012

I know I know. I don't want it to go fast, but I do want it to pull its weight

I've just come from a 2.5NAD 90, so to be doing 60 up this one particular hill is a revelation. Previously, I'd be getting a 75mph run-up at the bottom and barely be doing 40mph by the top!

Dr_evil · Nov 19, 2012

A snorkel or poor air filter won't help either if it has those

tombardier · Nov 19, 2012

The air filter looks good, and I haven't got a snorkel. I'm coming around to thinking that it's gearbox instead of engine now haha. I'll see how it is up that hill when I lock it in to 3rd gear

rollin danny · Nov 19, 2012

Drop manually into third on auto box to stop it hunting. You can overheat the box and **** it up if you dont!

Tomp · Nov 19, 2012

thebiglad said:
Yes it can be frustrating but you learn with time how to get the best from these autos. Experiment a bit using different pedal pressure to see how the gearbox reacts.

Also remember:

Weight: 2200kgs

Power: 111 or 120 bhp

Drivetrain: Permanent four wheel drive

The above is not a recipe for a 'ball of fire' vehicle

:lol::lol:

tombardier · Nov 22, 2012

OK, I've tested this whilst locked in to 3rd gear, and I'm still getting it seem like it's hunting for gear, although I still suspect an engine fueling problem more than an autobox problem. The investigation continues!

danspann · Jan 27, 2016

sorry to raise an old post but has this issue been sorted?

New Disco, and a hesitation problem at higher RPM and under high load

tombardier

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