My Range Rover has healed itself (any ideas what’s going on?)

So, I bought this car about three weeks ago. It clearly had a problem as it was catastrophically under powered. Two owners from new, last serviced at 100k now at 105. However, the last service was in 2010! Got home very slowly and sent it off to an excellent independent Range Rover specialist for a full check over and rigorous service. Other than a few minor issues all was well and the mechanic found that a vacuum pipe had detached itself from something and this was preventing the turbo from working. After collection, the car was transformed and in the words of the mechanic who test drove it, ‘it now performs like every other DSE’

This was great. My previous RR was a 4.6 and over the next two weeks I drove the car a fair bit, did a few miles and was beginning to get used to the way that a diesel performed.

The only irritation was a loud vibration from all over the dash whist accelerating that disappeared when the car changed up to 3rd (auto). However, and this is the weird bit. Yesterday when off on a trip the vibration completely disappeared and the car has increased in power considerably. Now I’m not going mad here there is a significant increase in power smoothness and driveability. It’s almost as if there is a different engine under the bonnet.

How, has this happened? Could it have been chipped some time ago and it’s just kicked in due to dodgy wiring? As it had only done about 4500 miles in 5 years, could just driving the thing have made the improvement? The bit I really don’t get is it is quite responsive now, not like the 4.6 but not that far off. What do I do to try and make sure that it maintains this form or have I stumbled on the words first self-healing Range Rover. It’s spooky.

with the engine being starved there could be a build up or a stoppage some where and its freed its self up and cleared it so its running as it should just see if it goes back if you go over bumpy ground then its a wire loose. glad you have it sorted. enjoy.

Not called "Christine" is it?..............................

I completely get the fact that driving 'Christine!' will get the old girl going better, but its the increase in power that I don't understand. If they were designed to be this pleasurable to drive, they would never have got the reputation of being so under powered. Someone on here (regarding a different post) suggested that I should get used to mobility scoters burning me off the lights. He was right until yesterday. I know I should have a look in the dreaded ECU case to identify any extra boxes of tricks, but being a colour blind halfwit, it scars the s**t out of me! Thanks all.

And the vibration. where the hell has that gone?

The mechanic has reconnected the pressure pipe to the MAP sensor that is all. They don't go to well if they are not getting fuel on boost.

Thanks very much. But! The improvement in performance was great after the MAP pipe was reconnected. However, this new boost of performance is the unexplained bit. There must be something more? It's very significant. God knows that I'm not complaining but learning would be good!

Diesels just need fuel and air. Guessing one or the other now flowing freely. When was the intercooler last cleaned? Maybe the renewed vigour from the turbo flushed it through a bit. Or maybe a blockage somewhere in the fuel line went through. The vibration is odd. Was there a misfire at all?

I have the DT. It is no racer but I wouldn't say it is underpowered. The fuel economy is pretty reasonable for a car of its size and weight and age.

No misfire but a small and irregular start conundrum. Cold is fine (ish) one day instant, the next quick but with a cough. Warm is a 3 second churn after half an hour standing. If an hour, could take a coupe of tries.

Sorry. To add. No idea if the intercooler has been cleaned, FSH but only have the book not the individual paperwork.

Possible the MAP sensor pipe was partially blocked....

When it was disconnected, there would be no boost fueling information so the ECU defaults to a basic fueling map....

Then your Mech reconnects this....but it is not 100% clear and has a blockeage....but the MAP sensor is now giving some more info to the ECU, and the ECU has begun to give revised fueling information....

All of a sudden, the blockage clears...the MAP sensor is now getting 100% of the boost pressure it should be getting, and this gives info to the ECU to correct the fueling and you get a better running engine.

As for the vibration, not sure.....maybe because the engine wasn't running 100%....and now it is.

My '99 DSE didn't have any chip fitted, but she would lift her skirt and scamp away when prodded.....

That makes sense. Many thanks. The vibration cleared as the engine improved so I assume that the vibration was due to some imbalance? Anyway, and I am feeling rather like a greedy schoolboy here, zapping everybodies knowledge and experiance. The starting issue? Should I just bite the bullet and go for a new diesel pump? Am a touch weird about things not working perfectly (sorry I know I have a p38!) or could it be timing. I don't want to fit an eBay hot start thing would prefer a perminant solution. Thanks, thanks. Can you buy people a cyber pint?

It could have been a clogged fuel injector?

Charles Banbury said:

Thanks very much. But! The improvement in performance was great after the MAP pipe was reconnected. However, this new boost of performance is the unexplained bit. There must be something more? It's very significant. God knows that I'm not complaining but learning would be good!

Click to expand...

Without the MAP sensor pipe fitted any chipping would have little effect. If it has been chipped, with the MAP pipe refitted you get the chip actually working and injecting extra fuel when on boost. Pretty simple really.

Charles Banbury said:

That makes sense. Many thanks. The vibration cleared as the engine improved so I assume that the vibration was due to some imbalance? Anyway, and I am feeling rather like a greedy schoolboy here, zapping everybodies knowledge and experiance. The starting issue? Should I just bite the bullet and go for a new diesel pump? Am a touch weird about things not working perfectly (sorry I know I have a p38!) or could it be timing. I don't want to fit an eBay hot start thing would prefer a perminant solution. Thanks, thanks. Can you buy people a cyber pint?

Click to expand...

What year is the car?

Grrrrrr said:

What year is the car?

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2002 DSE.

Shouldn't have a hot start problem then.

The same weird self healing happened to my sisters p38, previously it was way underpowered, one week ago i've changed injection pump and injectors to the set from previous engine with blown head/head gasket. Obviously nothing has improved. Changed MAF and MAP sensors with new ones, and still nothing. But 3 days ago something transformed engine performance and also all vibrations/acceleration noise has gone!
I have no idea what happened, even when underpowered all live data parameters were ok. Now it goes like it's chipped, but it's not!

I think it must be related to fault somewhere in engine wiring loom or ECU, as it's not explainable.

N2O said:

The same weird self healing happened to my sisters p38, previously it was way underpowered, one week ago i've changed injection pump and injectors to the set from previous engine with blown head/head gasket. Obviously nothing has improved. Changed MAF and MAP sensors with new ones, and still nothing. But 3 days ago something transformed engine performance and also all vibrations/acceleration noise has gone!
I have no idea what happened, even when underpowered all live data parameters were ok. Now it goes like it's chipped, but it's not!

I think it must be related to fault somewhere in engine wiring loom or ECU, as it's not explainable.

Click to expand...

I fixed it, the bill is in the post.

N2O said:

The same weird self healing happened to my sisters p38, previously it was way underpowered, one week ago i've changed injection pump and injectors to the set from previous engine with blown head/head gasket. Obviously nothing has improved. Changed MAF and MAP sensors with new ones, and still nothing. But 3 days ago something transformed engine performance and also all vibrations/acceleration noise has gone!
I have no idea what happened, even when underpowered all live data parameters were ok. Now it goes like it's chipped, but it's not!

I think it must be related to fault somewhere in engine wiring loom or ECU, as it's not explainable.

Click to expand...

MAF sensor is for measuring exhaust gas being ingested when EGR is operating. Nothing to do with how engine runs other than that.