TD5 - Horrendous MPG

TD5 - Horrendous MPG

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Discussion

JCW

Original Poster:

905 posts

214 months

Tuesday 18th May 2010
quotequote all
I've recently bought a TD5 90, which seems to like a drink of the dark stuff big time. Prior to the remap (Twisted Performance) it could only manage 300 miles to a 60 litre tank cruising at 65mph. Since the remap, nothing has improved with the worst case being 240 miles cruising at 65-70mph on motorways; so no change then.

As far as I can tell, there's no diesel leaking and I've tried to be as sympathetic as possible to improve fuel economy, but so far with no success. I've put injector cleaner into the tank with no improvement.

So, any ideas? I'm sure I must be able to achieve more and am wondering if there could be a problem with the MAF sensor? One discussion with a Spanish mechanic suggested that each fuel rail had independant lobes on the cam which 'may need balancing'?

Any ideas gratefully received!

Blackpig2

626 posts

188 months

Wednesday 19th May 2010
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It doesnt sound right, thats for sure. My TD5 Discovery does 600+ on a tank, I would post your question on LRO website, plenty of help on there.

300bhp/ton

41,030 posts

197 months

Wednesday 19th May 2010
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22mpg does seem a little low, but then again my Tdi Disco only does about 20-21mpg.

I suppose some questions to ask, what size and type of tyres are you running? Larger mud terrains will affect mpg.

Do you have air con? This, even when off will affect mpg. Also if the pump is stuck on (can happen) it will have a big affect).

What type of roads do you drive on? Are you at higher altitude or drive in hilly area's a lot?

When you are cruising, how heavy are you on the throttle, it's easy to cruise yet still use lots of throttle input which means poorer mpg.

How does the car drive? Does it freewheel well? As in the handbrake or something else isn't dragging?

Apart from that I'm out of constructive idea's I'm afraid.

ilaishley

167 posts

248 months

Wednesday 19th May 2010
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I had a remapped TD5 disco 2 and only ever got 22 mpg

Regards

Ian

300bhp/ton

41,030 posts

197 months

Wednesday 19th May 2010
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Blackpig2 said:
It doesnt sound right, thats for sure. My TD5 Discovery does 600+ on a tank, I would post your question on LRO website, plenty of help on there.
Disco has a much bigger tank than a Defender.

sunbeam_alpine

7,078 posts

195 months

Wednesday 19th May 2010
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That seems pretty bad. I get the following -

Average use: 28mpg
Economical driving (doesn't happen often): 33 mpg
Towing very heavy trailer (nearly 3.5 tonne): 19 mpg

I'm in Belgium, so just in case I've messed up the conversion, we use the following:

Ave: 10 liter/100 km
Eco: 8.5 l/100km
Towing: 14 l/100km

Mine is a standard (not chipped etc. TD5) year 2000.

Blackpig2

626 posts

188 months

Friday 21st May 2010
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300bhp/ton said:
Blackpig2 said:
It doesnt sound right, thats for sure. My TD5 Discovery does 600+ on a tank, I would post your question on LRO website, plenty of help on there.
Disco has a much bigger tank than a Defender.
Yup, and it still does 30-32 on normal runs..

JCW

Original Poster:

905 posts

214 months

Tuesday 25th May 2010
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Thanks all for your input. Will report back when I have tried the various suggestions.

JCW

Original Poster:

905 posts

214 months

Friday 2nd July 2010
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I've ruled out the tyres as they're the same size as the ATs I had on before. The MAP/MAF has been cleaned and whilst there was some sludge in the MAP it wasn't overwhelming so didn't bother with the rest of the inlet manifold, but may have to re-visit this area when I'm back in the UK.

Even driving like Miss Daisy, I can only get around 320 to the tank which works out around 24mpg. OK, achievable but it's torturous driving round like that ranging from 642m altitude to sea level!

Could there be an injector problem? I take your point about the EGR but it seems the jury's out as to whether this will affect economy reading other threads on the matter?

The brake pads have been changed to rule out binding, plus an oil change and its only done 65k on a 02 plate.

Puzzled. Thanks for the useful photo showing the MAP by the way.

macar

378 posts

177 months

Saturday 3rd July 2010
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Had three landies with Td5 engine (a 110, a 90 and a Disco), all were chipped after running in and the mpg didn't change appreciably. The 90 averaged 26mpg, the 110 25mpg and the Disco 24mpg- all were standard wheel/tyre set ups. The latest engines are less fuel efficient !!?
Td6 Disco, chipped, 21mpg and a Tdci 90 23mpg.
All vehicles same type of journey, mixed town, motorway and A road use.

JCW

Original Poster:

905 posts

214 months

Saturday 3rd July 2010
quotequote all
fesuvious said:
Oh, may I ask you a question:

At your '65-70mph on motorways' what revs is your 90 sitting at?
Unfortunaely, it doesn't have a thrashometer and my backside isn't calibrated accurately enough for RPM.

Thanks as ever for the replies people. Looks as if the EGR will have to wait for my return to the UK which is a bummer as I could have done with the improved fuel economy on the way back.


fergus91

72 posts

214 months

Saturday 10th July 2010
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hmm intresting reading this, i wouldent feel too bad though,yours isnt the worst out there haha. ive recently bought a td5, and with mainly motorway miles it is doing around 14 mpg. will be looking at the intake as soon as i can get the time to as this is insane

vette70

76 posts

186 months

Wednesday 11th August 2010
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your problem is almost certain to be the injector seal washers that sit on the bottom of the injector they will need replacing as deisel is getting into the engine oil. had the same problem on my td5 defender couldent work out were the fuel was going in the end i was burning almost £10 a day .

you can check out this problem by checking the oil level on the dipstick if it is way over maximum that is most likely to be deisel not oil get it sorted quick or you will end up having a hefty bill for a new cylinder head .

Cheers
D .

robgee1964

105 posts

226 months

Sunday 15th August 2010
quotequote all
JCW said:
I've recently bought a TD5 90, which seems to like a drink of the dark stuff big time. Prior to the remap (Twisted Performance) it could only manage 300 miles to a 60 litre tank cruising at 65mph. Since the remap, nothing has improved with the worst case being 240 miles cruising at 65-70mph on motorways; so no change then.
The TD5 discos generally seem a bit thirstier than the Tdi's. Defenders seem to give worse mpg than disco's too, maybe due to the lower gearing.

600 miles on a tankful from a Td5 disco might be possible, but bear in mind its nearly a 20 gallon tank. Real world mpg is more like 26-27, they are really crap if you boot them too. Therefore I could believe about 25 from a td5 90.

To be honest there's far too much potential for trouble with a Td5, than I'm comfortable with. You hear of people spending a fortune on the things, chasing all manner of bizzarre faults. Its worth remembering that the Army refused to take them at all, and stuck with the 300Tdi.

Edited by robgee1964 on Sunday 15th August 22:28

West4x4

672 posts

179 months

Sunday 15th August 2010
quotequote all
robgee1964 said:
JCW said:
I've recently bought a TD5 90, which seems to like a drink of the dark stuff big time. Prior to the remap (Twisted Performance) it could only manage 300 miles to a 60 litre tank cruising at 65mph. Since the remap, nothing has improved with the worst case being 240 miles cruising at 65-70mph on motorways; so no change then.
The TD5 discos generally seem a bit thirstier than the Tdi's. Defenders seem to give worse mpg than disco's too, maybe due to the lower gearing.

600 miles on a tankful from a Td5 disco might be possible, but bear in mind its nearly a 20 gallon tank. Real world mpg is more like 26-27, they are really crap if you boot them too. Therefore I could believe about 25 from a td5 90.

To be honest there's far too much potential for trouble with a Td5, than I'm comfortable with. You hear of people spending a fortune on the things, chasing all manner of bizzarre faults. Its worth remembering that the Army refused to take them at all, and stuck with the 300Tdi.

Edited by robgee1964 on Sunday 15th August 22:28
The army was never offered TD5's except as civilian white fleet which they used. The wolf contract with 300tdi's was started before the TD5 came out. They can be thirsty and the old scholl electronic haters will never love them but they were in production for 9 years pretty long in modern times and that 5 cylinder growl is an awsome noise!!! I loved mine

robgee1964

105 posts

226 months

Sunday 15th August 2010
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West4x4 said:
the old scholl electronic haters will never love them but they were in production for 9 years pretty long in modern times and that 5 cylinder growl is an awsome noise!!! I loved mine
Ironically the electronics seem to give little trouble. They are nice when new, but an older vehicle they can be a risky bet, especially pre 2002. As well as the various "failure modes", there's plenty of stupid things designed in. For example, officially you can't rebore them, or regrind the cranks. Even the heads aren't supposed to be skimmed. So a relatively minor problem could end up being an uneconomic repair. As for the production run, 9 years isn't much really, especially considering the volumes were not massive.

Just out of interest, how old was yours when you got rid?


zebraman

8 posts

155 months

Tuesday 28th January 2020
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I’ve got a 2005 TD5 110 and over the last 60,000 miles l have achieved a reliable 26mpg
That’s in mainly town driving/shorter journeys for my business.
It’s got a mild remap around 25bhp but apart from that is standard.
On the motorway it’s not much different, l get maybe 28mpg sitting at 65mph.
During a road trip around Northern Spain we achieved 32mpg which l have never managed in the UK.
We also have a 90 TD5 Defender and the fuel consumption on that is similar....26mpg.

Throttle Body

450 posts

180 months

Tuesday 28th January 2020
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robgee1964 said:
As well as the various "failure modes", there's plenty of stupid things designed in. For example, officially you can't rebore them, or regrind the cranks. Even the heads aren't supposed to be skimmed. So a relatively minor problem could end up being an uneconomic repair. As for the production run, 9 years isn't much really, especially considering the volumes were not massive.
Isn't the TD5 a BMW-sourced engine, or is my memory failing me? I remember them as being very rattly-sounding units from when I had a Discovery TD5.

neutral 3

6,504 posts

177 months

Wednesday 29th January 2020
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I have had 2 x Discovery 300 Tdi a 95 3 door and a 94 5 door ( which I still have ) and have recently bought a late facelift TD-5. It’s on circa 162,000 miles and I’ve had to throw some ££ at it, inc a new LUK dual mass flywheel, a Valeo full clutch kit, clutch fork and rod ( Britpart ) a new clutch slave cylinder, a new clutch master cylinder ( being fitted today - hope this finally sorts the awful clutch out ) new h / d rear springs ( I tow a lot ) 4 x Monroe Adventure gas shocks, a new fuel tank return pipe ( my one missed the re call for this ) and was leaking fuel, two Armstrong all terrains on the front, an exhaust down pipe, two pieces of welding to the rear chassis ( they All need this ) a right lower front ball joint. Plus an engine oil and filter change.
I searched for ages for a Non sunroof / manual gear box / late built one / in a decent colour, in as good a condition as I could find, paying £2,000 for it. It came with its Service book and lots of invoices.
As for economy, Ime very pleased, towing a car on a trailer across Holland on two seperate occasions @ a steady 65/70 mph, it’s doing 30 odd to the gallon.
Some low life cut the Cat from my current 300TDi , so we fitted a de cat pipe to it, which really improved the performance and economy. But the TD-5 is definitely more economical.
The extra length in the boot area is also Very welcome !! I’m off to Europe again soon in it.

Edited by neutral 3 on Wednesday 29th January 15:06

FiringOnThree

65 posts

75 months

Wednesday 12th February 2020
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Have you checked your fuel pressure regulator isn't dumping fuel in?
Part number you'll need is LR016319 if it has 2 pipes coming off it, LR016318 if it has 3 pipes if that's the case