Classic Q&A
Your technical questions answered by our experts
I’ve just bought a Y-plate P38 2.5-litre DT with 112,000 miles on the clock. I love this style of Range Rover but, even by P38 diesel standards, it goes like an asthmatic slug. It feels like it wants to get going but is being held back by something.
The auto box often seems reluctant to change up until it’s screaming it’s head off, but not always. And starting it up is a good time for a wager on instant fire-up or long drawn out turning over until it gives in and starts.
I’m thinking about an ECU remap. Is it worth it, and have you any other suggestions? Please bear in mind that when I read the Technical section of LRM, on the 1 to 5 spanners scale I know my limits and 1 spanner is an absolute maximum for me.
After ten years of regret at selling my last Range Rover I want this to be a great car, not a pup. And, joy of joys, it’s on coils. I have no plans for serious off-roading.
Oh yes, and has anyone got any walnut trim pieces available to posh it up a bit? It is after all only a DT spec.
Dave Pilling
The first thing I must stress very strongly is that you must not have an ECU upgrade or remap done until you get the car running correctly. This is a mistake that many people make and, all that will happen, is that the car will run even worse than before.
As far as the possible causes of the lack of power are concerned, it really could be absolutely anything, and you need to book the car in to a local specialist and invest a couple of hours worth of labour in having the whole engine and injection gear checked out.
Because of the numerous possibilities, it is important to have the correct checks made first, to avoid unnecessary replacement of expensive parts. You need to be asking them to do a computer diagnostic check, but also ask them to look at live data when the engine is running, in addition to looking for fault codes. Very often there can be one sensor not reading correctly that can cause poor running and/or poor starting, yet it will not be significant enough to flag up a fault code.
You also need to ask them to check the timing. All the fuel lines, intercooler and intercooler hoses, injector leak-off readings and the fuel pressure from the in-tank electric fuel pump need to be checked.
Do a general engine service to make sure that the oil and filters (oil, air and fuel) are good, and check the turbo boost pressure.
I would also recommend having the gearbox oil and filter changed, because a bad auto gearbox can cause an engine to be sluggish, and it may well cure the intermittent gear change problem.
Once all of the above items are in good condition and working as they should, you will either have the car back to something like original power or you will have to start looking at mechanical problems such as wear in the injectors, injector pump or the engine itself.
Obviously, with over 100,000 miles recorded, you have to expect some wear, but too much in any one component will have a very noticeable effect on an engine that was not renowned for speed in the first place.
I have suggested that you take the car to a garage for these checks to be made because you suggest that you are not a confident DIY mechanic.
Although it may cost you a couple of hundred pounds to get all this work done, you are buying some peace of mind with the knowledge that everything is working as it should.
Sam Clarke