Nightmare problem...

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Emma79

New Member
Posts
6
Location
France
Have an 03 Disco td5.
It started to jerk when driving, found oil on the ecu plug, changed loom and gasket, cleaned out ecu, still jerking. Have changed MAF sensor, (very low air reading) no difference.
Has had a diagnostic, no error codes.
Just as an aside, it threw a manifold bolt a couple of months ago, which has now been replaced along with two others. Related?
Any ideas as to what is causing this thing to resemble a kangaroo?
 
Was the ecu plug itself cleaned or just harness changed? There will be residual oil in the loom from the connection underside of the cam carrier all the way back to ecu so may take a few goes to clean everything out. If oil has made it into ecu in excessive fashion it would need opening up and cleaning. Not everyone advises opening your ecu case, I did and it was fine.

Get some contact cleaner or brake cleaner and spray the granny out of the red plug on loom and socket on ecu then check weekly until nothing else comes out.

Otherwise is it jerking just on take up of drive or in a higher gear under decent load? Low revs or higher up the rev range?
Intermittent or every time you drive a certain way?
 
You tried unplugging the MAF sensor and running around with it unplugged? Also pop the map sensor out in the intake and give that a quick clean
 
Starts fine, but as soon as you start to accelerate, you can feel that it is going to start to jerk.
It was intermittant, but is now constant.
The ecu was opened, as there was oil in there, (but the jerking was occurring BEFORE ecu was opened)
The ecu has had a good clean, the red plug has also been sprayed to death.
As before, it has had a diagnostic, but there were no fault codes, but the MAF sensor was showing low output, so that was changed today, and has made no difference.
 
Starts fine, but as soon as you start to accelerate, you can feel that it is going to start to jerk.
It was intermittant, but is now constant.
The ecu was opened, as there was oil in there, (but the jerking was occurring BEFORE ecu was opened)
The ecu has had a good clean, the red plug has also been sprayed to death.
As before, it has had a diagnostic, but there were no fault codes, but the MAF sensor was showing low output, so that was changed today, and has made no difference.

Has it ever cut out whilst driving? If sensors are all fine and clean I'd be looking at your fuel system or drivetrain. Drivetrain is easiest to check, a Google of td5 fuel system gremlins will probably scare you but not too complicated

Any clunks, bangs or grinding noises? Check prop uj's and sliders for play, check rubber donut rear prop to axle for cracks and perishing. Check handbrake isnt binding on. Just check every conceivable thing underneath from gearboxes to wheels lol

Unless you feel certain it's an engine/fuel delivery fault.

Edit @sierrafery Could it be overboost?

If it's happening when the turbo is or should be kicking in anything between 1600rpm to about 2000 depending on your set up could be turbo related
 
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Has it ever cut out whilst driving? If sensors are all fine and clean I'd be looking at your fuel system or drivetrain. Drivetrain is easiest to check, a Google of td5 fuel system gremlins will probably scare you but not too complicated

Any clunks, bangs or grinding noises? Check prop uj's and sliders for play, check rubber donut rear prop to axle for cracks and perishing. Check handbrake isnt binding on. Just check every conceivable thing underneath from gearboxes to wheels lol

Unless you feel certain it's an engine/fuel delivery fault.

Edit @sierrafery Could it be overboost?

If it's happening when the turbo is or should be kicking in anything between 1600rpm to about 2000 depending on your set up could be turbo related

It cut out once while driving, which alerted us to the fact that the loom was failing and oiling up the ecu.
When the ecu was reconnected, the engine went straight into limp mode, and then a couple of hours later, it started without an issue.
As I said, it has a new loom, clean ECU, new MAF sensor, the MAP sensor has also been cleaned out.
It threw a manifold bolt a little while ago, and it was around then that these further issues started......
 
In that case you need to investigate why the manifold warped in the first place and see if there's any underlying problem.

Has it been remapped?
Bigger tyres than standard?
Overworked?

Personally I'd be looking at fuel system as well, alongside checking out why manifold warped and broke a stud
 
In that case you need to investigate why the manifold warped in the first place and see if there's any underlying problem.

Has it been remapped?
Bigger tyres than standard?
Overworked?

Personally I'd be looking at fuel system as well, alongside checking out why manifold warped and broke a stud

As far as we know, not remapped, and definitely not overworked.
How would I find out what would cause the manifold stud to break? I am just a novice here!
 
As far as we know, not remapped, and definitely not overworked.
How would I find out what would cause the manifold stud to break? I am just a novice here!

Tbh I doubt it's linked, probably coincidence.

Do you use a garage for everything or do some work on it yourself?
 
Tbh I doubt it's linked, probably coincidence.

Do you use a garage for everything or do some work on it yourself?

We use a mechanic.... where we live in France, is pretty basic and the french garages do have a tendency to 'repair' one problem, for another one to surface a week or two later... :(
We have an English mechanic about an hour from us, he came to us the other day, to do the diagnostic, which showed no error codes, he did the loom, repaired the manifold, he has also changed the starter motor, the power steering pump, brake line...... he is actually a trained mechanic, and has been doing it a number of years, but this has got him scratching his head!
 
If the mechanic is equipped with proper gauges tell him to measure the pressure in the FPR in the FT sensor's port and if it's below 4 bar the pump's HP side is gone and you need a new one... the fuel delivery system is not covered by diagnostics so any engine running issue without fault codes is usually on that side, the engine can start and run without power on LP too so you can still hear the pump running while it doesnt deliver enough pressure.
 
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