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Omega Help Area => Omega General Help => Topic started by: Shackeng on 29 October 2011, 09:53:58

Title: TD fuel consumption
Post by: Shackeng on 29 October 2011, 09:53:58
My TD has just started using significantly more fuel according to the computer. Most of my driving is less than 20 miles, and it usually shows about 29 mpg. It has suddenly this week dropped to about 24 with no change in journey lengths or driving style.No sign of leaks anywhere. I'm about to juggle the cars to get it in the garage to have a look at pipes, filter, etc. Any suggestions to assist diagnosis? :y
Title: Re: TD fuel consumption
Post by: TheBoy on 29 October 2011, 10:50:47
If you can get a code reader on it, coolant temp sensor (engine one, not dash one) worth a look.  Fuel consumption will increase slightly this time of year (colder, more electrical load, diesel has more antiwaxing agents in), but that seems excessive.

If chipped, worth doing a calculation the old fashioned way. To be honest, even 29mpg seems very low :o.  Yours is a manual tractor IIRC?
Title: Re: TD fuel consumption
Post by: Shackeng on 29 October 2011, 13:31:20
No auto. Can I paper clip this?
Title: Re: TD fuel consumption
Post by: Seth on 29 October 2011, 13:41:25
No auto. Can I paper clip this?

Possibly Chris - try this: http://www.omegaowners.com/forum/index.php?topic=90581.0
Title: Re: TD fuel consumption
Post by: Shackeng on 29 October 2011, 15:58:22
Thanks Jaime, Byron, seems to paper clip OK, I get only the 12's, so no codes. I am guessing that I should get code 14 or 15 if I had a coolant temp sensor fault. :-\
Title: Re: TD fuel consumption
Post by: Seth on 29 October 2011, 16:29:53
Thanks Jaime, Byron, seems to paper clip OK, I get only the 12's, so no codes. I am guessing that I should get code 14 or 15 if I had a coolant temp sensor fault. :-\
Personally Chris, I'd brim the tank, use the car for a few days, then re-brim it and take things from there.

I've not known auto-boxed TDs to return favourable fuel consumption figures - but they're my own experiences! ;)
Title: Re: TD fuel consumption
Post by: Elite Pete on 29 October 2011, 16:33:36
Mines showing 57mpg approx but it is chipped so its miles out ::)
Title: Re: TD fuel consumption
Post by: Shackeng on 29 October 2011, 17:44:50
Thanks Jaime, Byron, seems to paper clip OK, I get only the 12's, so no codes. I am guessing that I should get code 14 or 15 if I had a coolant temp sensor fault. :-\
Personally Chris, I'd brim the tank, use the car for a few days, then re-brim it and take things from there.

I've not known auto-boxed TDs to return favourable fuel consumption figures - but they're my own experiences! ;)

I'm fairly confident that the computer has not suddenly decided to give a dodgy mpg, I've fitted a new air filter, although the old one was only a few thousand old and not very grubby, and cleaned the plastic bit at the front, plus the egr and inlet pipes. I'll see if that improves things before I start worrying seriously. :y
Title: Re: TD fuel consumption
Post by: Shackeng on 29 October 2011, 17:51:58
If you can get a code reader on it, coolant temp sensor (engine one, not dash one) worth a look.  Fuel consumption will increase slightly this time of year (colder, more electrical load, diesel has more antiwaxing agents in), but that seems excessive.

If chipped, worth doing a calculation the old fashioned way. To be honest, even 29mpg seems very low :o.  Yours is a manual tractor IIRC?

Currently uncipped awaiting AR35 fitment. MG TF overhaul and kitchen installation taking priority at present.
Title: Re: TD fuel consumption
Post by: Dodger on 29 October 2011, 19:24:59
My auto tractor returns about 25-27 around town, and 35-37 on a run, and has done since in the 4 years I've owned it. These figures seem about right according to the owners handbook, and considering mines covered 183K!! :y
Title: Re: TD fuel consumption
Post by: Seth on 29 October 2011, 20:28:30
My auto tractor returns about 25-27 around town, and 35-37 on a run, and has done since in the 4 years I've owned it. These figures seem about right according to the owners handbook, and considering mines covered 183K!! :y

That's about the norm for an auto-boxed TD IME ;)
Title: Re: TD fuel consumption
Post by: zirk on 29 October 2011, 22:06:05
ive had a couple of 2.5 TD's the later being a manual would never fall below 35 mpg in London's rush hour and 45 plus on a run, the auto one I had, long gone, would still do 30 mpg in London's traffis withup to 40 on a run. Remeber having issues with the auto including power loss at high speed and high mpg, did the usual checks including diesel magic, turned out to be the Maf, worth a check.

Chris.
Title: Re: TD fuel consumption
Post by: Shackeng on 30 October 2011, 10:16:16
ive had a couple of 2.5 TD's the later being a manual would never fall below 35 mpg in London's rush hour and 45 plus on a run, the auto one I had, long gone, would still do 30 mpg in London's traffis withup to 40 on a run. Remeber having issues with the auto including power loss at high speed and high mpg, did the usual checks including diesel magic, turned out to be the Maf, worth a check.

Chris.

Will do thanks.
Title: Re: TD fuel consumption
Post by: Shackeng on 30 October 2011, 10:19:03
MAF? Just read a post on this, and its seems to do....well not much, unless at high revs, whereas I drive Miss Daisy so I don't think its going to be that. :-\
Title: Re: TD fuel consumption
Post by: aaronjb on 30 October 2011, 13:22:26
Thanks Jaime, Byron, seems to paper clip OK, I get only the 12's, so no codes. I am guessing that I should get code 14 or 15 if I had a coolant temp sensor fault. :-\

Just to cover this as it got skipped over - you'd only get a code 14/15 (or whatever the code is for the coolant temp sensor) if it was open circuit or wildly out of calibration returning 'impossible' readings to the ECU..

If it started reporting just 'consistently cold' then the ECU can only assume that the engine is, in fact, cold and fuel accordingly.. unfortunately the only way to tell that is with live data..
Title: Re: TD fuel consumption
Post by: GmasterT on 30 October 2011, 13:33:30
Check for shite on the intercooler/fan, good indication is if the fuse has popped under the bonnet relays :)
Title: Re: TD fuel consumption
Post by: Shackeng on 31 October 2011, 13:20:32
Thanks to both last posters. I'll check the fuse, and hopefully get the live data checked soon. :y :y :y

Title: Re: TD fuel consumption
Post by: Shackeng on 01 November 2011, 14:05:31
Right, I've checked all the 30A fuses are OK in the relay box. How/where do I access the intercooler fan to check it? Although I guess it must be working if the fuse is OK.
Title: Re: TD fuel consumption
Post by: tunnie on 01 November 2011, 14:27:23
with that kind of consumption, i'd want a V6 under my right foot  :o
Title: Re: TD fuel consumption
Post by: Shackeng on 01 November 2011, 15:23:29
with that kind of consumption, i'd want a V6 under my right foot  :o

Got a 3.2 one of those as well, which is doing about the same!
Title: Re: TD fuel consumption
Post by: Seth on 01 November 2011, 17:27:09
Right, I've checked all the 30A fuses are OK in the relay box. How/where do I access the intercooler fan to check it? Although I guess it must be working if the fuse is OK.

It's hidden by the front end of the O/S/F wheel-arch liner ;)
Title: Re: TD fuel consumption
Post by: Shackeng on 01 November 2011, 17:58:20
Thanks Byron, is that accessed by removing the wheel arch?
Title: Re: TD fuel consumption
Post by: Seth on 01 November 2011, 18:29:31
Thanks Byron, is that accessed by removing the wheel arch?

Yes, so I'm reliably informed! ;)
Title: Re: TD fuel consumption
Post by: TheBoy on 01 November 2011, 18:30:57
The intercooler won't affect consumption (well, not by much).  Worth getting the I/C fan working for other reasons (and keep it working by dumping the viscous).
Title: Re: TD fuel consumption
Post by: TheBoy on 01 November 2011, 18:32:17
Thanks Byron, is that accessed by removing the wheel arch?
Remove the rubber cowling, unplug the fan (vital!!), turn the blades by hand a couple of dozen times, then connect it to 12v for a hour, occasionally lubricting the bearing
Title: Re: TD fuel consumption
Post by: Shackeng on 01 November 2011, 18:43:52
Thanks Byron, is that accessed by removing the wheel arch?
Remove the rubber cowling, unplug the fan (vital!!), turn the blades by hand a couple of dozen times, then connect it to 12v for a hour, occasionally lubricting the bearing

 Presumably accessed via the O/S wheel arch as per Seth's post :y
Title: Re: TD fuel consumption
Post by: TheBoy on 01 November 2011, 18:46:50
Thanks Byron, is that accessed by removing the wheel arch?
Remove the rubber cowling, unplug the fan (vital!!), turn the blades by hand a couple of dozen times, then connect it to 12v for a hour, occasionally lubricting the bearing

 Presumably accessed via the O/S wheel arch as per Seth's post :y
Personally, I'd drop the bumper off, much easier :y

But, yes, behind the bumper, just in front of wheelarch liner, drivers side...
Title: Re: TD fuel consumption
Post by: Shackeng on 01 November 2011, 18:52:43
Thanks J., it'll have to wait a bit now due a hand operation tomorrow. >:(
Title: Re: TD fuel consumption
Post by: GmasterT on 04 November 2011, 08:21:31
The intercooler won't affect consumption (well, not by much).  Worth getting the I/C fan working for other reasons (and keep it working by dumping the viscous).

Dunno, I unleashed about 5mpg on clearing mine, was pretty clogged though

[/quote]
Personally, I'd drop the bumper off, much easier :y

But, yes, behind the bumper, just in front of wheelarch liner, drivers side...
[/quote]

Agreed, bumper off :)
Title: Re: TD fuel consumption
Post by: Shackeng on 04 November 2011, 09:49:22
Thanks GM, I'll have a go when the stitches are out :y :y :y
Title: Re: TD fuel consumption
Post by: Shackeng on 18 November 2011, 13:54:55
Thanks a lot guys, my hand is now serviceable, and sure enough, the i/c fan was not turning. Blocked with leaves and fairly stiff. I have now got it turning freely, and runs fine with 12v input. However, it still feels a little tight. I shall put back as I need it mobile, but I have ordered a new fan to go on as I feel it will only seize again fairly soon. Have to do a motorway run next week, so it will be interesting to see how the mpg has altered. :y
Title: Re: TD fuel consumption
Post by: TheBoy on 18 November 2011, 14:51:50
Thanks a lot guys, my hand is now serviceable, and sure enough, the i/c fan was not turning. Blocked with leaves and fairly stiff. I have now got it turning freely, and runs fine with 12v input. However, it still feels a little tight. I shall put back as I need it mobile, but I have ordered a new fan to go on as I feel it will only seize again fairly soon. Have to do a motorway run next week, so it will be interesting to see how the mpg has altered. :y
If you have standard fan wiring (ie, nobody's butchered it), the best way to stop it seizing is to remove viscous fan.
Title: Re: TD fuel consumption
Post by: Shackeng on 18 November 2011, 14:54:30
Thanks a lot guys, my hand is now serviceable, and sure enough, the i/c fan was not turning. Blocked with leaves and fairly stiff. I have now got it turning freely, and runs fine with 12v input. However, it still feels a little tight. I shall put back as I need it mobile, but I have ordered a new fan to go on as I feel it will only seize again fairly soon. Have to do a motorway run next week, so it will be interesting to see how the mpg has altered. :y
If you have standard fan wiring (ie, nobody's butchered it), the best way to stop it seizing is to remove viscous fan.

I have taken off this morning for the winter, but having had an overheat in the summer this year, I shall put back on for warm weather next year. :y
Title: Re: TD fuel consumption
Post by: TheBoy on 18 November 2011, 14:56:25
Thanks a lot guys, my hand is now serviceable, and sure enough, the i/c fan was not turning. Blocked with leaves and fairly stiff. I have now got it turning freely, and runs fine with 12v input. However, it still feels a little tight. I shall put back as I need it mobile, but I have ordered a new fan to go on as I feel it will only seize again fairly soon. Have to do a motorway run next week, so it will be interesting to see how the mpg has altered. :y
If you have standard fan wiring (ie, nobody's butchered it), the best way to stop it seizing is to remove viscous fan.

I have taken off this morning for the winter, but having had an overheat in the summer this year, I shall put back on for warm weather next year. :y
oooooohh, that warrants further investigation :o

Was you either towing or booting it at the time?
Title: Re: TD fuel consumption
Post by: Shackeng on 18 November 2011, 15:02:39
Thanks a lot guys, my hand is now serviceable, and sure enough, the i/c fan was not turning. Blocked with leaves and fairly stiff. I have now got it turning freely, and runs fine with 12v input. However, it still feels a little tight. I shall put back as I need it mobile, but I have ordered a new fan to go on as I feel it will only seize again fairly soon. Have to do a motorway run next week, so it will be interesting to see how the mpg has altered. :y
If you have standard fan wiring (ie, nobody's butchered it), the best way to stop it seizing is to remove viscous fan.

I have taken off this morning for the winter, but having had an overheat in the summer this year, I shall put back on for warm weather next year. :y
oooooohh, that warrants further investigation :o

Was you either towing or booting it at the time?

Not really, going up a farly long steep hill in the very hot weather. The light came on and straight off again when I eased off, and I put the VF back on until this morning. Temp, at normal cruise is now where it should be, midway.
Title: Re: TD fuel consumption
Post by: Shackeng on 18 November 2011, 15:05:04
Presumably the i/c fan is linked to the turbo operation? Also I am puzzled as to why the fuse was not blown with a seized fan. ???
Title: Re: TD fuel consumption
Post by: TheBoy on 18 November 2011, 16:25:12
Presumably the i/c fan is linked to the turbo operation?
No, linked to electric cooling fans

Also I am puzzled as to why the fuse was not blown with a seized fan. ???
Big fuse, small motor (actually, sometimes it does blow the fuse, but often not)
Title: Re: TD fuel consumption
Post by: Shackeng on 18 November 2011, 18:00:28
Presumably the i/c fan is linked to the turbo operation?
No, linked to electric cooling fans

Also I am puzzled as to why the fuse was not blown with a seized fan. ???
Big fuse, small motor (actually, sometimes it does blow the fuse, but often not)

So I need to get the cooling fans on to check it. I guess there should be enough 'suck' through the small grill to tell if its on or not. ???
Title: Re: TD fuel consumption
Post by: maracus on 18 November 2011, 20:08:06
;) you'll hear it and feel it. Does the intercooler fan not only come on over a set intake temp?

I had mine on a switch :)

Also, without the viscous, mine would get too hot in traffic in hot weather. But my front auxiliary fans were non workers...
Title: Re: TD fuel consumption
Post by: Shackeng on 18 November 2011, 22:35:36
Well I've never checked if the main fans work, I guess I should. :y
Title: Re: TD fuel consumption
Post by: Vamps on 19 November 2011, 00:41:17
My auto tractor returns about 25-27 around town, and 35-37 on a run, and has done since in the 4 years I've owned it. These figures seem about right according to the owners handbook, and considering mines covered 183K!! :y

That is no better than a 2.2 petrol..... :o :o :o
Title: Re: TD fuel consumption
Post by: TheBoy on 19 November 2011, 08:32:54
Presumably the i/c fan is linked to the turbo operation?
No, linked to electric cooling fans

Also I am puzzled as to why the fuse was not blown with a seized fan. ???
Big fuse, small motor (actually, sometimes it does blow the fuse, but often not)

So I need to get the cooling fans on to check it. I guess there should be enough 'suck' through the small grill to tell if its on or not. ???
You'll hear it if you stick your ear near the corner its in.
Title: Re: TD fuel consumption
Post by: TheBoy on 19 November 2011, 08:45:42
;) you'll hear it and feel it. Does the intercooler fan not only come on over a set intake temp?

I had mine on a switch :)

Also, without the viscous, mine would get too hot in traffic in hot weather. But my front auxiliary fans were non workers...
It comes on when coolant reaches a temp hot enough to bring on main electric fans.

With the viscous fan attached, it seems to overcool the rad (most TDs with viscous fans I've seen have had knackered viscous couplings), thus in traffic, the electric fans never come on, and the intercooler fan starts to seize due to lack of use, and its low intake position.


If you are not towing, if your TD overheats without a viscous, you have another problem. The common ones are:

1) Radiator sludges up on these engines at about 120k (whether fitted to Omega, Rangie or beemer)
2) The awful waterpumps occasionally shed parts of an impellor, usually just before shedding the whole lot!
3) Poor oil servicing earlier in life (remember, these had 4.5k service intervals that nobody ever obeyed) causes a black sludge, which blocks the cooling jets.


The black sludge thing, in my experience, doesn't improve with subsequent quick oil changes (although mine was a fairly extreme case).  I had to resort to the work of Satan, and pop a chemical flush in mine.

There is one cooling jet per cylinder, so even if just one is blocked, that will have an effect


Once I'd sorted my tractor, the viscous was removed, and it never went above 96C on the prefacelift gauage (so 92C on facelift gauge), be it on high speed runs up the motorways, up inclines, or around Lake District mountain passes with the back end trying to beat the front ::).  It was ragged everywhere.
Title: Re: TD fuel consumption
Post by: Shackeng on 19 November 2011, 13:46:38
Thanks for all that Jaime.

I suspect my i/c fan has not needed to work as you suggest. The cooling system has been flushed and 'should' be OK.
A new metal impellered pump was fitted last year.
The temp has been sitting at 95 or thereabouts with the viscous fitted, which is now removed for winter.
The cooling jets, hmmmm...., it was serviced by VX for the first 40,000 or so, and more frequent oil changes since, so I may have a blocked jet problem, which may have caused my one off overheat on a very hot summer day this year.
What chemical cleaner did you use, and do you recommend it?
Also, I have removed the viscous cowl, which I assume should not be a problem.
Title: Re: TD fuel consumption
Post by: TheBoy on 19 November 2011, 14:09:29
I suspect my i/c fan has not needed to work as you suggest. The cooling system has been flushed and 'should' be OK.
Rad possibly still sludged up, probably needs to come off, and harsch solvents used...

A new metal impellered pump was fitted last year.
:y

The temp has been sitting at 95 or thereabouts with the viscous fitted, which is now removed for winter.
The cooling jets, hmmmm...., it was serviced by VX for the first 40,000 or so, and more frequent oil changes since, so I may have a blocked jet problem, which may have caused my one off overheat on a very hot summer day this year.
What chemical cleaner did you use, and do you recommend it?
I used one can of http://www.gasolutions.co.uk/engine-treatmetns.html - top right one

Also, I have removed the viscous cowl, which I assume should not be a problem.
:y
Title: Re: TD fuel consumption
Post by: Shackeng on 19 November 2011, 15:21:47
Interesting, the Tecsol suppliers are local to me, so I will pop in to pick up a can.
I'm sure I've seen it, but can't now find, at what temp the rad fans should switch on? I ran it up to about 98 this AM and they did not come on.
Title: Re: TD fuel consumption
Post by: Shackeng on 19 November 2011, 16:10:18
Both front fans (but not the i/c fan?) work with the AC on, so electrically are OK. I have no paper clip codes, so does this suggest that the engine coolant temp sensor is serviceable? If so, at what temp should the fans come on? :y
Title: Re: TD fuel consumption
Post by: TheBoy on 19 November 2011, 16:15:59
Electric cooling fans should be on low speed at about 96/92 (prefacelift/facelift) and on high speed at about 98/95 (pre/facelift).
Title: Re: TD fuel consumption
Post by: Shackeng on 19 November 2011, 16:23:15
Electric cooling fans should be on low speed at about 96/92 (prefacelift/facelift) and on high speed at about 98/95 (pre/facelift).

Mine is MFL. They did not come on above that this morning, so I guess the sensor may be Donald, despite no codes. Is it the one above the drain cock?
Title: Re: TD fuel consumption
Post by: TheBoy on 19 November 2011, 16:26:19
Electric cooling fans should be on low speed at about 96/92 (prefacelift/facelift) and on high speed at about 98/95 (pre/facelift).

Mine is MFL. They did not come on above that this morning, so I guess the sensor may be Donald, despite no codes. Is it the one above the drain cock?
From memory, the low speed sensor is the top one on a TD (just under top ran hose).

Easy test, short it with a paperclip, low speed fans will come on (even with ign on, so mind fingers!)
Title: Re: TD fuel consumption
Post by: Shackeng on 19 November 2011, 16:40:56
Electric cooling fans should be on low speed at about 96/92 (prefacelift/facelift) and on high speed at about 98/95 (pre/facelift).

Mine is MFL. They did not come on above that this morning, so I guess the sensor may be Donald, despite no codes. Is it the one above the drain cock?
From memory, the low speed sensor is the top one on a TD (just under top ran hose).

Easy test, short it with a paperclip, low speed fans will come on (even with ign on, so mind fingers!)

Also, once I have sorted the fans, I need to check the coolant sensor that supplies the ECU. Can you remember where this one is Jaime?
Title: Re: TD fuel consumption
Post by: TheBoy on 19 November 2011, 16:45:19
Electric cooling fans should be on low speed at about 96/92 (prefacelift/facelift) and on high speed at about 98/95 (pre/facelift).

Mine is MFL. They did not come on above that this morning, so I guess the sensor may be Donald, despite no codes. Is it the one above the drain cock?
From memory, the low speed sensor is the top one on a TD (just under top ran hose).

Easy test, short it with a paperclip, low speed fans will come on (even with ign on, so mind fingers!)

Also, once I have sorted the fans, I need to check the coolant sensor that supplies the ECU. Can you remember where this one is Jaime?
In head, under large intake/plenum

There are 2, the 1 pin one is for gauge, 2 pin one for ecu
Title: Re: TD fuel consumption
Post by: Shackeng on 19 November 2011, 17:15:23
Thanks :y :y :y