Declining fuel economy from 300tdi

[JamesH]

Hi

Ive noticed the last half dozen tanks of fuel have yielded disappointing economy. Ive done a quite a few country trips and if anything I was expecting an improvement. I'd say nearer to 11.5l/100 than my usual 10.5. It's being experienced over both tanks and Ive have a look underneath, no sign of weeping leaks.

It has 223K km on the clock and the injectors haven't been done.

If power has reduced it's done so so slowly I haven't really noticed.

Smoke, some under power but nothing too worrying.

Can't rule out fuel quality as I buy a lesser known cheap brand (Liberty). Ive been using the same supplier for a long period.

Any thoughts?

[Chucaro]

Hi

Ive noticed the last half dozen tanks of fuel have yielded disappointing economy. Ive done a quite a few country trips and if anything I was expecting an improvement. I'd say nearer to 11.5l/100 than my usual 10.5. It's being experienced over both tanks and Ive have a look underneath, no sign of weeping leaks.

It has 223K km on the clock and the injectors haven't been done.

If power has reduced it's done so so slowly I haven't really noticed.

Smoke, some under power but nothing too worrying.

Can't rule out fuel quality as I buy a lesser known cheap brand (Liberty). Ive been using the same supplier for a long period.

Any thoughts?

If there are not restrictions in the air inteke and the fuel filter and lines are clean I would test the injectors and calibrate if needed.
Also have a look each outlet port in the injection pump if they are clean. Some times they give problems with blockage if the fuel filtration it is not good.

[discoveryseries1]

Hi

Ive noticed the last half dozen tanks of fuel have yielded disappointing economy. Ive done a quite a few country trips and if anything I was expecting an improvement. I'd say nearer to 11.5l/100 than my usual 10.5. It's being experienced over both tanks and Ive have a look underneath, no sign of weeping leaks.

It has 223K km on the clock and the injectors haven't been done.

If power has reduced it's done so so slowly I haven't really noticed.

Smoke, some under power but nothing too worrying.

Can't rule out fuel quality as I buy a lesser known cheap brand (Liberty). Ive been using the same supplier for a long period.

Any thoughts?
cupple of things to say, first 11 is not bad, im fitted out with both front and rear bars, and some other nick nacks, also i have a power chip. im advraging around 14l/100 with mud tyres (31") second thing is that if your out in the country alot of dust roads can fill the air filter quickly, im not sure if you know or not but diesel engines have to air throttle so they constantly have air pumped through reguardless of throttle position, hense the filter plugs faster than a petrol engine would. a k&N filter is a good option because they preform better and can be washed hence are cheeper than the 30$ ryco deal you get at s cheep auto.

as for diesel im going to duck down as to not get hit by any one throwing tomatos, but there is no such thing as cheeper fuel. if its crap it will be cheep , if its cheep it will be crap, if its imported from singapore you will be probably burning more of it hence no saving. i dont want to sound too self righouse but i always buy from shell, i know they refine it in australia and they contole the grade to australian standerds. just look at it as it comes out of the bowser, its clear and crisp. it has to be better. for a few extra cents per L you will probably get more out of your fuel filter wich is about 60 bucks. so if your filling your tank with mud and filtering it for 60 bucks and burning more fuel its not woth it for me. ok im going to get off the soap box.

last check tyre pressures and mud in rims, its easy miss tyre pressures on a 4wd as they almost look the same low. i prefer 40 psi around town in my mud tyres altho they can reach 65 i find they are best at 40.

let us know how you go.

also as for fuel, altho you may have used the same supplyer, they may have tryed a diffrent batch, or may have used a diffrent supplyer.

if i couldent get shell fuel i would go moble, for the reasion they are the second and only other fuel company that refines in australia that i am aware of. both of wich are in melbourne.

[JamesH]

It's coming up due for a minor service but I'll take a look at the air filter. Not sure I'd know a slightly manky filter if I saw one.

I'm on top of the tyre pressure. I'm using good ole fashioned 7.516s

I hear what you're saying about fuel but Ive been suckered in because this place is local and I get an extra 4c off from shopping at my IGA which I'd do anyway. But it's food for thought.

[Jock The Rock]

When were your valve clearances last checked?

[JamesH]

When were your valve clearances last checked?

Ummm, about twelve months, maybe 18.

[Jock The Rock]

Ummm, about twelve months, maybe 18.

Roughly howmany ks ago was that?

[discoveryseries1]

It's coming up due for a minor service but I'll take a look at the air filter. Not sure I'd know a slightly manky filter if I saw one.

I'm on top of the tyre pressure. I'm using good ole fashioned 7.516s

I hear what you're saying about fuel but Ive been suckered in because this place is local and I get an extra 4c off from shopping at my IGA which I'd do anyway. But it's food for thought.

no worries mate, we all have to do what we have to do. best rule of thumb with filters is hold it up to a light if you can see clear light braking through it she is good, if you cant, how the hell can air get through it ? lol when you buy a new filter hold it up to a light and you will see the diffrence, in a pinch wack the filter (with care) against somthing like a board durty side down. you will be surprized how much comes out. and it will get you buy untill you can get a new one.

dont try to wash a paper filter as it will turn to mud and further seal the dust togeather like cement ! ( sounds like the voice of experence)

[LandyAndy]

Gidday James
Sip on a Pimms mate:cool::cool::cool:
I agree with Jock,get the valve clearances done if you havent in the last 50000ks.They effect the time the valve is open for the engine to get its fair suck of oxygen.Our Trytoo went so much better every time I adjusted them.Its relatively easy IF you are mechanically minded,if not get a GOOD mechanic to do it.
Next check,are you getting full throttle??? The TDi can suffer from a stretched cable.EASY CHECK.
AT FULL OPERATING TEMP get an assistant to hold the power pedal FLAT TO THE FLOOR.Dont wory it cannot EXPLODE,its governed.NOW,see if you can manipulate the mechanical lever on the fuel pump to see if it can move further than the cable is pulling.If it does respond,a new cable is well worth installing,keep the old one for your travel spares kit!!!
GOODLUCK!!!
Andrew

[bcj]

I used Liberty for a couple of months untill I noticed fuel economy deteriorated, switched back to my old supplier- all's ok now
Your handbrakes not dragging is it?
Brett
110 300tdi

[jakeslouw]

1) Check for oil in the IC.
2) Run 500ml of good non-synth two-stroke thru a full tank of diesel to clean up the injector tips and combustion chambers
3) Have the turbo boost checked: if the turbo is not healthy, your consumption starts to suffer
4) Check your oil for diesel residue: could be injector seals

[rick130]

[snip]
a k&N filter is a good option because they preform better and can be washed hence are cheeper than the 30$ ryco deal you get at s cheep auto.

[snip]



no worries mate, we all have to do what we have to do. best rule of thumb with filters is hold it up to a light if you can see clear light braking through it she is good, if you cant, how the hell can air get through it ? lol
[snip]


Don't use a K&N or any other washable cotton gauze filter in a 4WD if you would like the engine to survive for a prolonged period ;)

In a 300Tdi

a) it isn't needed, OE filters in a Defender flow more than enough air in a stock engine, or a Donaldson or Fleetguard filter is a better bet and it will fit in the stock housing (less restrictive again and more paper area)

b) a K&N lets far too much through, the small stuff that wears bores ;)

I'll dig up the K&N filter tests we've done on here or just PM isuzurover and ask what he thinks of K&N's.

Some reading here (links) http://www.aulro.com/afvb/good-oil/37343-air-filters-cleaning-k-n-test-definitive-answer.html

[rick130]

1) Check for oil in the IC.
2) Run 500ml of good non-synth two-stroke thru a full tank of diesel to clean up the injector tips and combustion chambers
3) Have the turbo boost checked: if the turbo is not healthy, your consumption starts to suffer
4) Check your oil for diesel residue: could be injector seals

I've run an ashless full syn two stroke as a pump lube, but I doubt it would move too much from the tips and chambers in one tank, even though JASO FD oils have pretty good detegency (and i don't think any mineral based oils can meet JASO FD ??)

A good diesel cleaner like Redline RL2 which has pretty strong detegents plus a syn two stroke for lubrication might be a better bet for a cleanup, and some fuel additives can be corrosive, so choose carefully.
I know that Redlines additives don't show on used oil analysis, unlike some.

A 300Tdi doesn't have the O ring problem of a TD5 either, mechanical injection, copper washers under the injectors ;)

[rick130]

[snip]

if i couldent get shell fuel i would go moble, for the reasion they are the second and only other fuel company that refines in australia that i am aware of. both of wich are in melbourne.

BP have refineries in Brisbane and Perth and refine diesel at both (and that's why BP Ultimate diesel is available in those two states)
Caltex and Shell have refineries in Sydney and Caltex spent a small fortune upgrading Kurnell for ULSD production.
Caltex has a refinery in Brisbane that produces ULS diesel too.
Can't remember if there's a refinery in SA/Adelaide ?
[edit] Port Stanvac refinery in Adelaide was mothballed by Mobil a while back apparently and is being demolished.

[rick130]

James, as the other fella's have suggested try some different fuel and definitely adjust the rockers, JC swears it makes a big improvement on the cars he services.

I've had economy variations just from the difference between summer and winter fuels here.

[JamesH]

Roughly howmany ks ago was that?

I haven't been away on a long distance trip for two years (:mad:) so I'd say Ive only done around 15000kms since the guy who serviced it reported the gaps were out and had adjusted them.

I added injector cleaner to each tank about 12 months ago and I might run it through again. According to my blog at the time it is called Dynafuel.

I'll also replace the fuel filter and after I do that I'll sell a kidney and try some BP super diesel.

Will report back in a month or two.

Thanks for all the great ideas everyone.

[Lucy]

first 11 is not bad, im fitted out with both front and rear bars, and some other nick nacks, also i have a power chip. im advraging around 14l/100 with mud tyres (31")

My 1997 Tdi has done 214000km I run 32" Muddies, with a bull bar and long range tank (heavy). I average 10L/100km. It doesn't get worse than 12.5l/100km on stockton beach. I'd be upset and worried with an average of 14l/100km - seriously.

How do you have a power chip on a mechanically injected vehicle? My pump has been tweaked to give me a bit extra.

[5teve]

1) Check for oil in the IC.


I have to do this on my td5 as economy has gone to peices.. changed the intercooler hoses at the weekend and was amazed how much oil was in there and the other side..

been looking at the provents too.. but as i have 2 td5s...

I'd be checking this just to be sure also...

As for BP ultimate... i lost a 100k's on the disco td5 the one time i tried it.. we generally use peak in both.. as we get the discount and the servo we use is the cheapest around (even over other peak servos)

Steve

[rick130]

My 1997 Tdi has done 214000km I run 32" Muddies, with a bull bar and long range tank (heavy). I average 10L/100km. It doesn't get worse than 12.5l/100km on stockton beach. I'd be upset and worried with an average of 14l/100km - seriously.

How do you have a power chip on a mechanically injected vehicle? My pump has been tweaked to give me a bit extra.

Some Disco's (hardly any made it to Australia ?) have an electronically controlled boost compensator instead of the mechanical one, with #1 injector having a sensor on it.
They actually can be 'chipped'.

My 'fender with the fuel turned up, 33" MT's, ladders on top, bull bar, winch, sidesteps and brush bars, etc, etc. tares out at around 2660kg with the gear I have in it all the time and mostly uses somewhere between 11.5 and 12.5l/100km whenever I've bothered checking (not often)
Defenders push a lot more air than a Disco too.

[Tombie]

[edit] Port Stanvac refinery in Adelaide was mothballed by Mobil a while back apparently and is being demolished.

More than demoilished... Its becoming a De-Sal plant :eek:

[Jock The Rock]

I haven't been away on a long distance trip for two years (:mad:) so I'd say Ive only done around 15000kms since the guy who serviced it reported the gaps were out and had adjusted them.

I added injector cleaner to each tank about 12 months ago and I might run it through again. According to my blog at the time it is called Dynafuel.

I'll also replace the fuel filter and after I do that I'll sell a kidney and try some BP super diesel.

Will report back in a month or two.

Thanks for all the great ideas everyone.

Quite a few people recommend rechecking them every 10,000km

An interesting thing I found with injector cleaner, I ran a can of Liqui Moly Diesel Cleaner through the Landy and it did make a difference. For one tank :( then it must have just gummed up again. Tassie diesel is horrible quality

[LandyAndy]

I haven't been away on a long distance trip for two years (:mad:) so I'd say Ive only done around 15000kms since the guy who serviced it reported the gaps were out and had adjusted them.

I added injector cleaner to each tank about 12 months ago and I might run it through again. According to my blog at the time it is called Dynafuel.

I'll also replace the fuel filter and after I do that I'll sell a kidney and try some BP super diesel.

Will report back in a month or two.

Thanks for all the great ideas everyone.

James
BP Ultimate isnt available in WA at the moment.
NOT ALL BP servos have the notice on the pumps!!!!
Andrew

[LandyAndy]

Quite a few people recommend rechecking them every 10,000km

An interesting thing I found with injector cleaner, I ran a can of Liqui Moly Diesel Cleaner through the Landy and it did make a difference. For one tank :( then it must have just gummed up again. Tassie diesel is horrible quality

I was doing ours on the Trytoo every 10000ks,was worth the effort!!!!
Andrew

[LandyAndy]

I have to do this on my td5 as economy has gone to peices.. changed the intercooler hoses at the weekend and was amazed how much oil was in there and the other side..

been looking at the provents too.. but as i have 2 td5s...

I'd be checking this just to be sure also...

As for BP ultimate... i lost a 100k's on the disco td5 the one time i tried it.. we generally use peak in both.. as we get the discount and the servo we use is the cheapest around (even over other peak servos)

Steve

Steve.
Bite the bullet,grab them ProVents!!!!
Stopped all the oil in the intercooler on my D2,getting one for the Deefer.
Andrew