TD5 not pulling as should and doing poor mpg??

hawky666 · Apr 22, 2013

Hi guys.
My mates just picked up a Disco TD5 on 2001 Yreg.
He's put injector cleaner through it as just a 'lets do that' thing, but he's done about 150 miles on App £40, thinks it should do better than that. Should it!! what should mpg be for very carefull driver?
He's also feeling that it's not performing as it should power wise and wonders what the normal culprits are to look for on one of these??

Another thing.. what is SRS?? he has this light coming up occasionally?

Any advice greatly appreciated.

pedros · Apr 22, 2013

Hard to say really about performance and there's potentially many causes as the search facility here will reveal. Has he driven another TD5 with which to compare performance? Can someone familiar with them have a drive and that may confirm if there is a problem or not. £40's worth of fuel for 150 miles is a bit much, but maybe not that far out.

SRS = Secondary Restraint System, that being the airbags. Seatbelts being the first. Check connections, there's one under the passenger seat. Failing that, might need plugged in and diagnosed.

OakleyPilot · Apr 22, 2013

Couple of possibilities that spring too mind:

Air Filter might need replacing.. this can have a dramatic effect on performance if it is old and grubby.

EGR valve stuck open, I know from first hand experience that this will badly hurt performance. I removed mine completely with a kit.

Turbo to intercooler and intercooler to intake manifold pipes delaminated.

Turbo malfunctioning.

Intake manifold leaking.

MAF and or MAP sensors failed or dirty.

All of the above can restrict performance, might be worth checking simple things like air filter and the hoses first. Then either hook up to a Hawkeye or Nanocom to get live data to see if everything is as it should be.

m500dpp · Apr 22, 2013

Thats 24 mpg which isnt far out (especially if its an auto which you havnt stated) If the owner is new to a Discovery and trying to drive it like a car that could also be a major contributor.

diver · Apr 22, 2013

Mines a manual TD5 and I am getting ~26mpg after injector cleaner, MAF sensor cleaned and getting the tyre pressures right. I personally think the tyre pressures had the most effect as I was getting 22.5mpg on the previous tank.
As already mentioned, driving style probably has more effect than anything else. I have seen claims of people getting 35mpg but I am a little sceptical.
Might try a new MAF sensor and see what happens but I doubt I will get much better. The thing does weigh over 2 tonnes and if you think about it, it is a 15 year old design.

hawky666 · Apr 22, 2013

Thanks guys.
My mate isn't new to disco's, nor is he hew to TD5's. He previously had a 110 twin cab with TD5 engine, and he reckons that did much better. He's one of those drivers that always seems to get the max out of anything he drives as he has a soft right foot for not only speed, but also braking.

Oh, and yes.. it is an auto. His 110 was a manual box, so maybe there is a difference there also.

David Pye · Apr 22, 2013

Sure he doesnt mean SLS rather than SRS?

If so that's the rear air suspension (if fitted)

hawky666 · Apr 22, 2013

He might do David. If i remember right, it came up on the dash towards top right as you look too it. Red letters.
Only seen it once and that was only a fleeting glimpse.

Is that a toughy to sort, if it is this?

TD5 not pulling as should and doing poor mpg??

hawky666

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pedros

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OakleyPilot

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m500dpp

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diver

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hawky666

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David Pye

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hawky666

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