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[TheBoy]

Probably one for Mr DTM....

Freeze frame data is pretty rubbish, covering no more than batt voltage, RPM, mileage etc.  Doesn't cover MAP or MAF readings or anything useful in this instance.

So I believe the -84 means its out of range at lower end, possibly short to ground?

I've looked for airleak, nothing obvious on airbox to throttle, and from turbo to intercooler, or from intercooler to manifold.  Can't really check intercooler without removing.  If the signal is out of range, would that imply its a pretty massive airleak?

Visible parts of loom look good.

As a general rule, the fault occurs at low RPM - 1500ish - and under very modest load in my experience, either just cruising or very light acceleration.


I hate just swapping parts, but tempted to try a new MAP/Temp sensor?

[Viral_Jim]

Do you have any way to do a pressured smoke test?

From memory that was the error that that 2.0 Disco 5 had that I kept for about a week then sent back to the dealer. Something about a mismatch between manifold pressure and the air coming into it. The local indie hooked it up to a Strap-On smoke machine and pressurised it, result was chuffing smoke from somewhere under the inlet manifold - would have been impossible to see without removing the engine from the car, but definitely there. 

My symptoms were that the car stuttered and stumbled at low rpm/load situations, like if parked at a set of lights and just rolling away when they turned green, say 25% throttle. Or when pottering through a 30 limit. If you gave it a shoe full it behaved normally.

[Marks DTM Calib]

Is the MAP sensor ok, reporting decent readings, and clean?

[TheBoy]

Is the MAP sensor ok, reporting decent readings, and clean?

The readings look viable to me for both MAP and temp (I think both are in same sensor on that one?).  I've never managed to see the readings when it does go into RP, and the freeze frame data recorded on that car is pretty poor sadly.

[TheBoy]

Do you have any way to do a pressured smoke test?

From memory that was the error that that 2.0 Disco 5 had that I kept for about a week then sent back to the dealer. Something about a mismatch between manifold pressure and the air coming into it. The local indie hooked it up to a Strap-On smoke machine and pressurised it, result was chuffing smoke from somewhere under the inlet manifold - would have been impossible to see without removing the engine from the car, but definitely there. 

My symptoms were that the car stuttered and stumbled at low rpm/load situations, like if parked at a set of lights and just rolling away when they turned green, say 25% throttle. Or when pottering through a 30 limit. If you gave it a shoe full it behaved normally.

I don't have access to such a tool.  I was toying with getting one, as I think the only place I could have an airleak is in the intercooler - but we know airleaks can be hard to find if no telltale oil/soot marks.  I'd checked top of intake manifold, but not under it, although its a bit sooty under there following an O ring failure on the EGR in intake pipe a year or 2 ago.

Our symptoms are RP when cruising mostly at probably 50ish, but can appear under gentle acceleration at around 50mph, like down the sliproad of a motorway.

Its been ongoing for a fair while now, but is too intermittent to get any readings - probably once every 6 - 12 weeks.

[TheBoy]

Is the MAP sensor ok, reporting decent readings, and clean?

I'll see if I can get some readings and post up over weekend.  Though the car is fine, right up until a few seconds before it pops up RP...

[Marks DTM Calib]

Are you using Topix or Pathfinder?

I would remove it and clean it anyway

[TheBoy]

Are you using Topix or Pathfinder?

I would remove it and clean it anyway

That car is SDD, assume Pathfinder won't work on it?

Already removed as "cleaned" the hole part (which wasn't too bad), but not poked anything too far down, or used chemicals.

[TheBoy]

Though I mostly used 3rd party diag tools for speed, if its something they can perform, as SDD does take an age to set up and get to the point when you can actually do something.

In fairness, it is faster on the XE than XJ, due to less options it has to check and communicate with