Omega Owners Forum - Poor MPG on 2.5TD

Essex Pete

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Woodford, Essex
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Drives: Omega 2.5 TD CD

Poor MPG on 2.5TD
07. Dec 2009 at 13:43

Recently my MPG has been getting less and less. A few weeks back after passing its MOT i serviced my car. New filters and oil change, including a full pot of diesel magic in the fuel filter. Since then i have been getting less and less MPG. When i got the car i could go nearly 600 miles to a tank, i am now struggling to get 400 miles, which equated to less than 30MPG.

Now i noticed this week that with the cold weather it hasnt been getting up to temperature, so i have a new thermostat on order which will be fitted at the weekend along with a full coolant flush.

It seems strange to me that it has got so bad since i did the service. I know the stat wouldnt have been helping, making the car run on cold run (rich), but is there anything else that could be an issue.

Also, when cold, the engine sometimes hesitates and the eml flashes on. This only happens when you lift off the throttle. If you press the throttle again quickly the car will try to throw you through the windscreen. This seems to happen as i change gear and the revs drop past 2000-1500 rpm. If i let the revs drop to idle before letting up the clutch it is fine, but if i mistime it, it seems like it is choking the engine.

The eml light doesnt stay on, just flashes, and there are no fault codes stored.

Sorry for the essay, but i would like to try and fix these issues sooner rather than later, its costing a fortune in diesel

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MickAP Omega Knight Offline Facelift 2.5TD Estate "Chipped" not anymore Posts: 1592 South Derbyshire Gender: Drives: Facelift TD estate but soon to be a 1.9 ???	Re: Poor MPG on 2.5TD Reply #1 - 07. Dec 2009 at 14:42 Have you checked the obvious like.......diesel leaks around filter seal/collar, leak off pipes and air filter box and connecting hoses/pipes. Have you accidently dislodged a hose/connection whilst doing your service? Mick
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zirk Omega Baron Offline Posts: 3146 London / Essex Gender: Drives: 3.0 MV6 FL Man Est, 3.0 MV6 FL Auto Est, 2.5TD PF Man Est, RWD RS Sapphire Cosworth	Re: Poor MPG on 2.5TD Reply #2 - 07. Dec 2009 at 14:50 As Mick says, plus does it feel like the Turbo's doing its job properly, Maf sensor (if its got one) could cause bad Mpg, spongy power. Other stuff not so obvious, brakes binding, partailly blooked exhaust.
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Seth

Omega Baron

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Posts: 4236
South Wales Valleys
Gender: male

Drives: 1999 2.5TD GLS Estate - Manual jobbie Woohoo !!!!!

Re: Poor MPG on 2.5TD
Reply #3 - 07. Dec 2009 at 15:41

MickAP wrote on 07. Dec 2009 at 14:42:

Have you checked the obvious like.......diesel leaks around filter seal/collar, leak off pipes and air filter box and connecting hoses/pipes. Have you accidently dislodged a hose/connection whilst doing your service?

Mick

Agreed Mick, but before delving further, I'd fill a new fuel filter with Forte and give it an Italian tune-up!

Also, use 'proper' diesel - avoid the supermarket-type juice.

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You can take a boy out of The Valleys - but you can't take The Valleys out of a boyo!

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MickAP

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Facelift 2.5TD Estate
"Chipped" not anymore

Posts: 1592
South Derbyshire
Gender: male

Drives: Facelift TD estate but soon to be a 1.9 ???

Re: Poor MPG on 2.5TD
Reply #4 - 07. Dec 2009 at 16:34

Seth wrote on 07. Dec 2009 at 15:41:

MickAP wrote on 07. Dec 2009 at 14:42:

Have you checked the obvious like.......diesel leaks around filter seal/collar, leak off pipes and air filter box and connecting hoses/pipes. Have you accidently dislodged a hose/connection whilst doing your service?

Mick

Agreed Mick, but before delving further, I'd fill a new fuel filter with Forte and give it an Italian tune-up!

Also, use 'proper' diesel - avoid the supermarket-type juice.

He's done that with diesel magic. Thumbs Up!

Suppose it won't harm doing it again.
Supermarket fuels, .....err I won't touch Sainsburys smokes like hell Embarrassed

but Asda and Tesco ok especially when they give you a voucher worth 5p off per litre Thumbs Up!

Mick

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Essex Pete

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Posts: 72
Woodford, Essex
Gender: male

Drives: Omega 2.5 TD CD

Re: Poor MPG on 2.5TD
Reply #5 - 07. Dec 2009 at 17:09

It seems to still pull really nice. maybe a bit slower than it used to but not really a noticable difference. It doesnt seem to smoke any more than in the past. I havent had a good look around the bay due to the shite weather, but i will get it in the garage at the weekend when i do the stat.

The EML when cold problem isnt new, it did that before the service, but then stopped doing it for a while during the summer, either that or i didnt notice it. Im going to check the connections to the temp sensor for the ecu make sure that isnt causing a problem. I had the egr off not long ago and cleaned it out, all seemed good.

It doesnt smell of diesel in the bay, or anywhere round the car, so i dont think it is leaking. I had the leakoff pipes replaced earlier this year as one split. It reeked of diesel then, so i would notice if it was leaking again.

Occasionally i have filled up at saisburys, but since it has been playing up i have run 3 tanks through it, one esso, one shell and one sainsburys. All have yielded less than 450 miles to a tank

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« Last Edit: 07. Dec 2009 at 17:11 by Essex Pete »

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damage consultant

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Posts: 116
falkirk (sunny scotland)
Gender: male

Drives: 2.5td omega/senator A

Re: Poor MPG on 2.5TD
Reply #6 - 07. Dec 2009 at 20:20

Your not alone with this fault Embarrassed

my tractor (auto) does exactly the same you lift foot off gas eml light flashes.
I'm also getting around the low 400miles per tank
I had codes 34 injector timing out of range and 64 fuel quantity out off range. I got codes cleared 2 months ago now there back with avengence.
Ive tried whynes fuel treatment had injectors & pump out and tested changed air & fuel filter every 14 days checked the timing the lists endless would be here all night wrighting.
I'm almost totaly bald with frustration not even my local garage will look at it every time they see me coming they s**t a brick and hide. Sad

.

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Turk Omega Baron Offline Posts: 3364 Llanelli, Wales Gender: Drives: Two tractors...a chipped manual 2.5td CD (F/Lift '00) & a Hardly-Movinson XL1200	Re: Poor MPG on 2.5TD Reply #7 - 07. Dec 2009 at 22:19 I get a quick flash of the EML on throttle lift off when cold and have done for months, but I'm getting around 41mpg general town and A roads and around 48mpg if sat at just below 70mph on a run.
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Andy H

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Cornwall
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Drives: 03 2.6 Elite Auto

Re: Poor MPG on 2.5TD
Reply #8 - 07. Dec 2009 at 22:46

damage consultant wrote on 07. Dec 2009 at 20:20:

Your not alone with this fault Embarrassed

my tractor (auto) does exactly the same you lift foot off gas eml light flashes.
I'm also getting around the low 400miles per tank
I had codes 34 injector timing out of range and 64 fuel quantity out off range. I got codes cleared 2 months ago now there back with avengence.
Ive tried whynes fuel treatment had injectors & pump out and tested changed air & fuel filter every 14 days checked the timing the lists endless would be here all night wrighting.
I'm almost totaly bald with frustration not even my local garage will look at it every time they see me coming they s**t a brick and hide. Sad

.

Is the injector pump driven by the cam chain on the traktor? Could the cam chain have jumped a sprocket and put the injector timing out?

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Previous vehicles: Viva, Chevette, Astra mk2, Carlton mk1, Astra mk2, Land Rover SerIII, Carlton Mk2, Range Rover, Omega 2.5 V6
"Deja Moo - The feeling that you've heard this bull somewhere before."

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damage consultant

Junior Member

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Posts: 116
falkirk (sunny scotland)
Gender: male

Drives: 2.5td omega/senator A

Re: Poor MPG on 2.5TD
Reply #9 - 08. Dec 2009 at 08:07

I had a problem some time ago when it shredded the cotter on the fuel pump and the nut fell off so engine stopped. mcallister fuel injection got it going but its never been the same we had a big barney bassicly I called him a usless a-hole that couldn't fix a puncture. yes its chain driven weve had all the front end off( belts and fan) and all the marks line up the only thing left it to replace the chain thats not a job for me.
the chain can be changed without taking the front end off engine to bits specialist job though.

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Andy H Omega Knight Offline Posts: 1833 Cornwall Gender: Drives: 03 2.6 Elite Auto	Re: Poor MPG on 2.5TD Reply #10 - 08. Dec 2009 at 09:47 I don't know if the sprocket is on a plain shaft or a tapered shaft. It might be that the cotter has sheared again and the taper is holding the sprocket on but out of alignment (or the keyways and cotter might be damaged and permitting sufficient misalignment to put the timing out).
Back to top	Previous vehicles: Viva, Chevette, Astra mk2, Carlton mk1, Astra mk2, Land Rover SerIII, Carlton Mk2, Range Rover, Omega 2.5 V6 "Deja Moo - The feeling that you've heard this bull somewhere before." IP Logged

Seth

Omega Baron

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If there's a 'system'
- play it ... !

Posts: 4236
South Wales Valleys
Gender: male

Drives: 1999 2.5TD GLS Estate - Manual jobbie Woohoo !!!!!

Re: Poor MPG on 2.5TD
Reply #11 - 08. Dec 2009 at 16:05

Andy H wrote on 07. Dec 2009 at 22:46:

damage consultant wrote on 07. Dec 2009 at 20:20:

Your not alone with this fault Embarrassed

my tractor (auto) does exactly the same you lift foot off gas eml light flashes.
I'm also getting around the low 400miles per tank
I had codes 34 injector timing out of range and 64 fuel quantity out off range. I got codes cleared 2 months ago now there back with avengence.
Ive tried whynes fuel treatment had injectors & pump out and tested changed air & fuel filter every 14 days checked the timing the lists endless would be here all night wrighting.
I'm almost totaly bald with frustration not even my local garage will look at it every time they see me coming they s**t a brick and hide. Sad

.

Is the injector pump driven by the cam chain on the traktor? Could the cam chain have jumped a sprocket and put the injector timing out?

There's two chains:
One connects the crankshaft to the pump, the other connects the pump to the camshaft.

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You can take a boy out of The Valleys - but you can't take The Valleys out of a boyo!

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damage consultant Junior Member Offline Posts: 116 falkirk (sunny scotland) Gender: Drives: 2.5td omega/senator A	Re: Poor MPG on 2.5TD Reply #12 - 08. Dec 2009 at 18:31 As far as i'm aware it a tapered shaft as you say the keyway could be damaged think its time to look on flea-bay for a new pump.
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Seth Omega Baron Offline If there's a 'system' - play it ... ! Posts: 4236 South Wales Valleys Gender: Drives: 1999 2.5TD GLS Estate - Manual jobbie Woohoo !!!!!	Re: Poor MPG on 2.5TD Reply #13 - 08. Dec 2009 at 18:49 damage consultant wrote on 08. Dec 2009 at 18:31: As far as i'm aware it a tapered shaft as you say the keyway could be damaged think its time to look on flea-bay for a new pump. I'll very soon have my previous '98 TD Estate up for sale. Had a brand-new pump and no.4 injector last year, and it's chipped too!
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damage consultant Junior Member Offline Posts: 116 falkirk (sunny scotland) Gender: Drives: 2.5td omega/senator A	Re: Poor MPG on 2.5TD Reply #14 - 08. Dec 2009 at 19:02 D.I.V.O.R.C.E was mentioned by my wife if I buy another car
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