Disco 2 Judder/Jerking/Kangarooing

Hi all,

1999 Discovery 2 Td5,
LOF Solid power spec clutch
Empire tuning map.

I have got a bad case of what only be described as jerking or kangarooing when I accelerate or let off the accelerator accompanied by a single click when i accelerate or let off.
I had this before fitting a Solid flywheel and thought it was the DMF, its better than it was so some of it must have come from there but its still there and makes it almost un-driveable in town situations especially if it gets a rhythm going.

Its hard to tell whether the motion is drive train or engine power related.
The click is obviously drive train but I haven't been able to locate where from as of yet.

Its almost like the engine just cuts fuel and it makes the car dive forward then when accelerating its all or nothing, there is no control over it, if you accelerate slowly it jerks violently back and forth until you either pull out of it or change gear.

I have had this issue for probably 2 years, its had new UJs, skimmed and dewebbed manifold, new rubber donut, new waste gate diaphragm, smf & clutch, 2nd hand front diff while looking for another issue, transfer box has been reconditioned although im not sure i trust them who did it.
The rest of the internet suggests it could maybe be the clutch switch, leaking exhaust or accelerator pedal, MAP sensor was found to faulty during the Remap so that was changed for a working one.

Nothing jumps out on live data and no faults logged that seem remotely anything to do with it.

Help please.
Thanks
Matt

Further to that, it also does it in high range and low range

Ukgrease_monkey said:

I have had this issue for probably 2 years,

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Hi, OK but what's the exact history of the desribed symptom? it just started out of the blue then you remapped it and made all the other things you said or how?

Ukgrease_monkey said:

MAP sensor was found to faulty during the Remap

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And before the MAP sensor was found faulty did it run well?

also was the original ECU chipped or replaced with a remapped one?

sierrafery said:

Hi, OK but what's the exact history of the desribed symptom? it just started out of the blue then you remapped it and made all the other things you said or how?

And before the MAP sensor was found faulty did it run well?

also was the original ECU chipped or replaced with a remapped one?

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I am sure it has always done it since i owned it (4/5 years ish) but I just put it down the DMF the MAP sensor made no difference to the driving of it that i could feel it was only when it was being mapped that we picked up that it wasn't reading correctly. Its the original ECU that was chipped by Empire

Thanks

Are you sure that the handbrake shoes are not sticking? Do you have cruise control?

sierrafery said:

Are you sure that the handbrake shoes are not sticking? Do you have cruise control?

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Yes not the handbrake shoes as they was replaced not long ago as the was contaminated with oil and not holding.
Cruise control works all good

So on cruise control no jerks at all when accelerating?

sierrafery said:

So on cruise control no jerks at all when accelerating?

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Not if done with the buttons. If with the pedal then yes

You should try to replace the pedal(TPS) then cos as the CC works the clutch switch and brake switch are both ruled out so is the fuelling

sierrafery said:

You should try to replace the pedal(TPS) then

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Is there a way to test it before replacing?

Only if you record an inputs fuelling log with nanocom from a drive to catch the symptom while accelerating then see if the TPS readings are "linear" or "jumping" while the speed is increasing

sierrafery said:

Only if you record an inputs fuelling log with nanocom from a drive to catch the symptom while accelerating then see if the TPS readings are "linear" or "jumping" while the speed is increasing

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Ok will give it a go

Post the file here when you'll get it and i'll check it too... if it was a fuelling issue it should have happened with CC acceleration too IMO

sierrafery said:

Post the file here when you'll get it and i'll check it too... if it was a fuelling issue it should have happened with CC acceleration too IMO

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Thanks

sierrafery said:

You should try to replace the pedal(TPS) then cos as the CC works the clutch switch and brake switch are both ruled out so is the fuelling

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+1^

@Ukgrease_monkey have you had any luck with this. Any updates please dont be like everyone else and drift off and not conclude your current situation..eagerly waiting your reply

landy-dandy said:

@Ukgrease_monkey have you had any luck with this. Any updates please dont be like everyone else and drift off and not conclude your current situation..eagerly waiting your reply

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@landy-dandy I have now sold the car and made the up/down grade to a d3 ...
but yes it was sorted before I sold it! It was backlash in the rear diff!

No other symptoms but I got hold of a 2nd hand one swapped it over and voila no more jerking.

Completely unrelated to anything that I thought it could have been

SOLVED

Ukgrease_monkey said:

I have now sold the car and made the up/down grade to a d3 ...
but yes it was sorted before I sold it! It was backlash in the rear diff!

No other symptoms but I got hold of a 2nd hand one swapped it over and voila no more jerking.

Completely unrelated to anything that I thought it could have been

SOLVED

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As you have now solved it I am a bit surprised that you didn't have vibration and noise while running with it, but there you go, you found it and solved it.
Surprised you didn't pick up on it when replacing the rubber donut. But then on my D1 I too changed the rubber donut and then had noise and vibration which turned out to be the pinion nut had come loose. similar but not the same I know.

Stanleysteamer said:

As you have now solved it I am a bit surprised that you didn't have vibration and noise while running with it, but there you go, you found it and solved it.
Surprised you didn't pick up on it when replacing the rubber donut. But then on my D1 I too changed the rubber donut and then had noise and vibration which turned out to be the pinion nut had come loose. similar but not the same I know.

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No noise or vibrations but it was lifted mud tyres loud exhaust and mapped etc...
The donut was changed quite a while before the juddering started and was still in good nick.

The diff was stripped after I sold it and it was 100% backlash

Ukgrease_monkey said:

No noise or vibrations but it was lifted mud tyres loud exhaust and mapped etc...
The donut was changed quite a while before the juddering started and was still in good nick.

The diff was stripped after I sold it and it was 100% backlash

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There is a recall issue on D2 rear axles, wonder if it was anything to with this?
In my case an indy had replaced the diff with a "good" secondhand unit as, on purchase, I could hear a "hum in the bum" and the garage that sold it would only allow a bunch of numpties, their favourites, to do the work, so the guys I took it to to find the error stood by it, in writing, I got the whole fee for the AA inspection refunded and the indy just left the "new" diff in as it would cost money to take it out and put a new one in. They charged me no more as all was good. Since then have had to replace the rear axle due to accident damage, in France, and the secondhand one does now have a little slam on taking off if I boot it hard, which is evidence of the recall not having been done. I can't get it done as I didn't buy the vehicle with it on, under recall, so I am just gentle with it. It is auto so I let the auto box take up the play gently.