96 2.5 Diesel Auto Issue

It's been a while since I've been on here, having had to change to far more economical motoring for a while.

Just a quick question regarding a Rangie I am having a look at.

The car seems fine except that it won't rev past around 3000rpm. I have had a good search and read around on here so my question is simply this. Is this likely to be a simple replacement of the 4th Injector sensor or would it need a diagnostic to determine whether it is one of many other possible faults? I understand the fuelling systems became much more complicated around 1997 but were much simpler prior to then and easier to fault find on?

I have owned and worked on a TD5 Discovery previously but not one of these 6 cylinder diesels.

Thanks for any advice regarding the likely cause(s) and especially costs.

Chris

The fueling system remained unchanged throughout the Diesels lifetime in the Range Rover...main difference was the inclusion of the EGR valve in 99 onwards..!!

Diagnostics will give some indications, but the most common reason is the MAP sensor (Manifold Absolute Pressure Sensor) that adjusts fuelling when the turbo comes on boost, around 2200rpm....or the little plastic pipe leading from under the plastic manifold to the MAP sensor is split...

A weak in tank pump can also affect higher speed running!

Thanks Saint

I have some experience with BMW diesel engines, having owned and worked on 3 Rover 75 CDT's. However the M47 engine seems to be very different in how it operates compared to the 6 cylinder unit in a P38.

I would have thought any of the items you have listed would not lead to such a precise cut-off point. As in they would lead to a loss of power when trying to push on hard. However, this particular vehicle seems to run fine, it just won't rev past around 3000? That is why I was thinking sensor and have read here that the sensor on the 4th injector seems to lead to a very similar fault.

I'll try and get down to have a close look at it, take my torch and have a good rummage around to see if the MAP sensor especially looks like it could be at fault.

The interesting thing is the pics of the car are taken outside an engine specialists (not shown in the pics but a little investigation reveals that is where it is) and they have obviously either diagnosed the problem and it's serious or they can't get to the bottom of it and the owner has given up.

A dodgy No 4 would lead to iffy running throughout the range as it is used as the Start of Injection timing sensor that is compared to the Crank Position...the ECU measures both readings and modulates/times the Fuel Injection Pump accordingly to maintain an efficient burn and injection quantity.

I would have thought that with an iffy No4 Lift Sensor, the running would be rough in all rev ranges.

The Turbo unit doesn't come on song until over 2200rpm or so, and before this the engine fuelling is adequate, after the boost pressure increases as the Turbo spins up, the fuelling needs to be adjusted to take the increased charge air into account, hence the reason for the MAP sensor, this tells the ECU what the manifold pressure is and as such to increase fuelling to compensate....

Wammers and Datatek are the two Diesel Gurus, so no doubt they will be able to offer further and better suggestions than I !!

Thanks again Saint.

The MAP sensor causes very few problems on the Rover, it's the MAF that causes most of the issues on that. Very similar issues to what the P38 has, limiting revs etc. That's why I came on here to investigate, to find the MAF seems to have very little effect on these 6 cylinder lumps. In fact from what I have read this 96 P38 won't even have a MAF.

It is a very cheap P38, but that's what I want, something I can tinker with and use as a second car. Especially with winters getting a lot worse around here and me living 1200 feet up. But at the same time, like everyone else, I can't afford a money pit.

Correct, MAF introduced for the 99MY onwards to coincide with the EGR valve and to keep the emissions within EU limits!

A Range Rover with faults will empty a bank balance rapidly....but if you are able to spanner your yourself and consider the purchase of a Diagnostics device - something like the Blackbox Solutions Nanocom or Bearmach Hawkeye - you will save a whole bunch...parts are no dearer than any other marque these days and are commonly available from third party suppliers (Stir clear of Britpart mind!)

Do some more searching on here, you'll find a wealth of information able to help you keep it on the road.

Whats the asking price, personally I would consider no more than £650-900 for an early Diesel with a fault as long as the rest of it works OK, and the bodywork is sorted.

When you say it doesn't rev past 3000 is this in Neutral as well I'm thinking fip or throttle peddle as saint has said injector trouble no 4 especially should have engine light on and would effect smooth running tick over ect and maybe a some black smoke

Saint - the seller is wanting under £1k for it and I would hope to get it for around £800.

defender - I'll check that out with him. He hasn't told me a great deal about the car at all. He's sent me some pics, where it looks in very good condition inside and out (don't they always) and he's told me it is perfect, except for this fault.

I'll hopefully be chatting with him later and will use what I've learned here today to help me find out a little more.

kissifur1972 said:

Saint - the seller is wanting under £1k for it and I would hope to get it for around £800.

defender - I'll check that out with him. He hasn't told me a great deal about the car at all. He's sent me some pics, where it looks in very good condition inside and out (don't they always) and he's told me it is perfect, except for this fault.

I'll hopefully be chatting with him later and will use what I've learned here today to help me find out a little more.

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Worth a chat be unless it had been plugged in or at least ask if he would mind a plug in and ask someone local , beer tokens ect I wouldn't bother harsh as it seems .

They always say it is perfect. No such thing. But go in with your eyes wide open and you might get a bargain.

Have been stung before, but not for a long time.

I know it won't be perfect, after all it is 17 years old and I know photos always make them look better than they are. But at the same time the seats don't look badly worn on the bolsters etc and the body does look very straight.

He's yet to get back to me on the basics, such as when the MOT runs out etc, so it is early days but am hopeful I'll be the owner of a Land Rover again in the near future. Even if it it's not this particular one.

Thanks for all the help guys. Knew I was right to log on here and check it out for advice.

Just a quick update. Have had an email from the seller and the MOT is out, he doesn't say when. The tax is also out and on closer inspection of the pics it looks to have been running out late 2012 in those. Am really not sure about buying a car with a known issue and no MOT. Especially as there will be added costs due to not being able to drive it home.

Walk away, plenty of them around....

Golden Rule: Never buy a Range Rover with Faults unless you know and are prepared for the costs and work involved in repairing it...

My thoughts exactly. If the 3k rpm problem is the only issue then why hasn't the owner MOT'd it?

Shame as it was priced right for me. I don't mind something that needs a little work. But only if I know what it needs and therefore have an idea of cost and how long it would take me to do it.

kissifur1972 said:

My thoughts exactly. If the 3k rpm problem is the only issue then why hasn't the owner MOT'd it?

Shame as it was priced right for me. I don't mind something that needs a little work. But only if I know what it needs and therefore have an idea of cost and how long it would take me to do it.

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Plenty more out there its just when you want one you can't find a decent bugger .

Saint.V8 said:

Walk away, plenty of them around....

Golden Rule: Never buy a Range Rover with Faults unless you know and are prepared for the costs and work involved in repairing it...

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Good advice. Although, when I was looking I couldn't find any that didn't have faults. I suppose you need to read up on what is DIYable and what isn't and make a decision. I don't think there are any P38s out there that are 100% functioning (well for more than a week anyway!)

stjohnsmythe said:

Good advice. Although, when I was looking I couldn't find any that didn't have faults. I suppose you need to read up on what is DIYable and what isn't and make a decision. I don't think there are any P38s out there that are 100% functioning (well for more than a week anyway!)

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I got lucky in that all mine needed was new heater plugs. Then I got unlucky as the alternator, blend motors, battery, various bushes, tyres, pullies and tensioners failed. Although they were spread out over the space of a year and a half.