How to get better MPG.. I know we drive a truck engined brick BUT!

[Jacob100]

Road Trip is a good app to help you track your MPG. I use the free version.

The above is for an unmodified 1998 100 series with BFG ATs, roof rack, snorkel and occasionally a 700-800kg camper trailer on trips all over the country and a fair bit in and around hilly Sheffield. It’s often in excess of 25mpg.

 

[AndycruiserguyLomas]

I'm with Ian and Jacob with around 23, running 265/70/17's GG at's . 5 spd auto too.

 

[SteveJB]

Suggest putting in you choice of injector cleaner remove and clean your airfilter give the engine a good service renew fuel filter and drive as if you got yer man sack under the thottle pedal as its better to sqeeze them gently than stamp on them

 

[moggy1968]

Suggest putting in you choice of injector cleaner remove and clean your airfilter give the engine a good service renew fuel filter and drive as if you got yer man sack under the thottle pedal as its better to sqeeze them gently than stamp on them

Or as my weapons instructor told me ‘squeeze it gently son, like a birds tits!’

 

[uHu]

Assuming this is a diesel, and the gallons of the UK size. (In an international forum, yap-yap-yap)
Also pre and post upgrade (2002-2003) matters, when talking 1HD-FTE engine.

15 mpg sounds like it would be US gallons, on a bad day even. Or a UZJ version.
If the brakes are dragging that much, you would have noticed. I suggest having the injectors checked asap.

Tyre pressure according to specs doesn't sound good. Which specs? The owner's manual says something like 32 psi, which is much too low for road use.

 

[Bmonck]

Some really interesting data points here. I was reading somewhere else on this forum earlier in the week and someone said they 28 mpg.
I have a 1992 1HDT diesel with BFG ATs. I get around 20-22 on long trips. I have used diesel cleaner but done nothing else. I don’t have a heavy foot and try to “respect” my 25 year old engine. I know my wheels need realigning. But brakes are clear.

I don’t think I have ever had the engine up to 3,000 revs. Should I push it up to blow it out? Clean it up? Seems high to me. At 2500 engines sounds confortable to me. I can cruise at 60-65 mph at around 2200 revs.
Should I be getting much higher mpg?
Thanks

 

[Alrightchief]

Assuming this is a diesel, and the gallons of the UK size. (In an international forum, yap-yap-yap)
Also pre and post upgrade (2002-2003) matters, when talking 1HD-FTE engine.

15 mpg sounds like it would be US gallons, on a bad day even. Or a UZJ version.
If the brakes are dragging that much, you would have noticed. I suggest having the injectors checked asap.

Tyre pressure according to specs doesn't sound good. Which specs? The owner's manual says something like 32 psi, which is much too low for road use.

Uk gallon 4.5L... Im now getting nearly 18mpg after a intake clean and doing the revive stuff... mine is a late 100 55 reg.... Tyres are at 45psi....

 

[uHu]

Chief, how many miles on yer cruiser? Have the injectors ever been checked? When you give the job to the best diesel injector place you can find, make sure they know the difference between early and late version hdj100, both re injector type and pressures.

 

[stumog]

What was your last car please?

I would almost put money on its driving style.

Do you have lots of stuff on the roof?

 

[moggy1968]

What was your last car please?

I would almost put money on its driving style.

Do you have lots of stuff on the roof?

I think regardless of driving style that’s low.

Have you checked the fuel system for leaks when the engines running?

 

[stumog]

You would be surprised how much difference driving with a lighter foot can make.

I can get anywhere between 15 and 25mpg out of my 80 depending on driving style. My discovery I can get from 26 up to 35 mpg slowing down to 65mph on the motorway.

If this was my truck I would change the filters certainly air, check all the brakes are free and then go for a run and see what comes back

 

[Bmonck]

Can I ask whether you all push these great motors much above 2,500 revs and whether you do it regularly? Whether to “clean “ the engine or just becos you cruise on motorways at 75-80
I rarely go above 2500. And mpg way way better at 65 than 75

 

[Towpack]

On the 24v 1HD-FT max power is at 3600 and max torque at 2500. The earlier 12v 1HD-T produces slightly less power at the same revs and less torque but at 2000rpm. Engines are at their most efficient (economical) at the rpm of max torque so that’s why economy will decrease the harder you push it. Certainly doesn’t do the engine any harm at all though and can be beneficial IMO, especially if it’s has long periods of light use, in town traffic etc. A good ‘blast’ through the gears or on the motorway is like a mechanical dose of salts!
Maybe it’s phsycological but I always think mine runs better after the trip to Scotland and back towing the caravan when the engine has had to work that much harder. JMO

 

[moggy1968]

Engines do like to work, although that’s different to being thrashed. 70mph does seem to be a big threshold, just below is much better mpg than just above.

 

[Gary820]

Mine likes to be revved, it's petrol so revs higher anyway, I can have a heavy foot and get the same sort of mpg as you're getting!

 

[Animal Mother]

Clean out intakes (and EGR).
Remove air pre-heater if fitted.
Fit Toyota air filter.
Fit new oil and fuel filter(s).
Fresh fluids in gearbox, transfer box and diffs.
Fresh fluids in engine.
Check IAT sensor (could it be running in "cold start mode"?).
Tyre pressures.
Add a bit of 2 stroke with every fresh tank of diesel.
Check brakes.
Remove excess weight (what are you lugging about?)

 

[Alrightchief]

Chief, how many miles on yer cruiser? Have the injectors ever been checked? When you give the job to the best diesel injector place you can find, make sure they know the difference between early and late version hdj100, both re injector type and pressures.

90 thou miles. I haven’t had the injectors checked. Because I knew about others issues with sending them off! Should I run the risk??

I think regardless of driving style that’s low.

Have you checked the fuel system for leaks when the engines running?

I kinda disagree driving style makes a huge difference. I have no leaks anywhere of any fluid!

On the 24v 1HD-FT max power is at 3600 and max torque at 2500. The earlier 12v 1HD-T produces slightly less power at the same revs and less torque but at 2000rpm. Engines are at their most efficient (economical) at the rpm of max torque so that’s why economy will decrease the harder you push it. Certainly doesn’t do the engine any harm at all though and can be beneficial IMO, especially if it’s has long periods of light use, in town traffic etc. A good ‘blast’ through the gears or on the motorway is like a mechanical dose of salts!
Maybe it’s phsycological but I always think mine runs better after the trip to Scotland and back towing the caravan when the engine has had to work that much harder. JMO

I agree they liked to be worked!

Clean out intakes (and EGR).
Remove air pre-heater if fitted.
Fit Toyota air filter.
Fit new oil and fuel filter(s).
Fresh fluids in gearbox, transfer box and diffs.
Fresh fluids in engine.
Check IAT sensor (could it be running in "cold start mode"?).
Tyre pressures.
Add a bit of 2 stroke with every fresh tank of diesel.
Check brakes.
Remove excess weight (what are you lugging about?)

Done done & done... I’d like to remove the air heater if possible as it’s quite a restriction! But unsure how and I don’t want to upset the eco sensors and all that! Have you done it yourself?

Would like to know more about the IAT sensor and it’s possition!

 

[Animal Mother]

Done done & done... I’d like to remove the air heater if possible as it’s quite a restriction! But unsure how and I don’t want to upset the eco sensors and all that! Have you done it yourself?

Would like to know more about the IAT sensor and it’s possition!

I'm not overly familiar with the cold start sensors etc on the 80/100 (I've a 120) sorry. I recently saw a post on here with someone who had just removed their air heater. I've looked but can't see it. Someone else may be able to point you in the right direction. I'm sure it was on an EGR cleaning thread.

 

[Sarge001]

I've read in another forum about a Cherokee, that was modified, mostly the underbody, panels were added to specific spots to improve the aerodynamics. From the exterior the car looks like unmodified, but with these mods, the guy got improved it's fuel economy from ~19mpg to ~30mpg. He posted about the aerodynamic simulations he made and the test results. If you are interested, I can search that thread and post it here.
Other than that, I am planning to do the same for my J95 D4D, I will model the whole underbody and make a few flow simulations, and I will modify the sub according to the results. If you are interested, I will post the whole process with the model, pictures and test results...
In the engine oil I use Metalube, it smoothed out the engine, I also use Metalube fuel additive. I used this stuff on all my cars, I have several hundred thousand of experience with these products and I love it. I will put in my diffs also soon.
With my stock car, using the additives I get 28.34mpg traveling at 68miles/hour.
The car: J95 D4D 3.0
4 speedAutomatic transmission
265/70/R16 tyres

 

[stumog]

I would love to hear about the underbody plates to smooth the air