Bad fuel economy

[Jasonsakr]

Hi guys,
Ive recently purchased a 2007 hilux sr5 turbo diesel and running 32" Mud tyres and have been experiencing bad fuel economy of 450km from a full tank. ive spoken to other owners and they all get over 500 km, does anyone know what the problem may be?

[boxhead55]

The engine load changes quite a bit when you increase to that size. From the data I have seen and depending on what the utes standard loaded weight you almost the same as every one else. You could try cleaning your maf sensor and map fitter and run higher pressures in your Tyres to lower the roiling friction.

But that figure of 400 to 550 seems to be the target depending heavily on what your right foot does.!

Hope I have helped.

[mcj91SR]

I run 285/70r17 bf km2s mud terrain on my 2012 d4d and get just about 650kms but like box head said its all about your right foot. I'm 22 and apparently drive like a grandpa!

[JUSTAUTOS]

We have found doing scv relearn with help this. We do this part of every common rail service

[cooganstein]

What does scv stand for? Do you need a scan tool or similar to do that?

[mattwhite]

You're probably aware you're speedo is about 10% slow on 32's?

[TTR]

Im running ARB Sahara Bar, MR bash plates (heavy!) dual batts, DP Chip on the highest setting, 3" zorst and drive it like like I stole it pretty much all the time. Running 32" KM2 muddies and standard gearing, tyre pressure at 36psi cold in the front and 26 in the back, unloaded. I"m getting close to 600 from a tank. Average around town is 10.5 l/100k. Highway down to at least 9.

As box head said, try cleaning your MAF and MAP sensors. Maybe and injector clean on the next tank fill.

[Monaz]

I run 32 BFG KM2 on mine, with a heap of extra weight and get between 500 and 550k's to a tank. Cleaning the MAF made no difference to fuel economy in my truck and in regards to the speedo...strangly enough with the 32's the speedo is exactly spot on. I have tested my speed against several GPS units all of which match the dashboard needle.

I think the only way to really fix it is either go back to the more aero-dynamic standard vehicle with no mods and skinny little 29 inch tires. There is always a compremise.

[StevenS]

Im running ARB Sahara Bar, MR bash plates (heavy!) dual batts, DP Chip on the highest setting, 3" zorst and drive it like like I stole it pretty much all the time. Running 32" KM2 muddies and standard gearing, tyre pressure at 36psi cold in the front and 26 in the back, unloaded. I"m getting close to 600 from a tank. Average around town is 10.5 l/100k. Highway down to at least 9.

As box head said, try cleaning your MAF and MAP sensors. Maybe and injector clean on the next tank fill.

600 a tank is about 12.5l per 100 km - something which matches your mods almost to a tee

[Jasonsakr]

Thanks guys ill give cleaning the maf and map sensor a go. Also what does SCV stand for?

[BIGFOOTJR]

Thanks guys ill give cleaning the maf and map sensor a go. Also what does SCV stand for?

Suction Control Valve

[StevenS]

SCV - Suction Control Valve

We have found doing scv relearn with help this. We do this part of every common rail service

How to you do this? I replaced the SCV on mine a few months ago and thought I had done the above by "readying fuel pump" or something along those lines, took about 5 seconds to do so I'm not sure if I did it right? Done via the techstream software

[Bourbydol]

I run 32 BFG KM2 on mine, with a heap of extra weight and get between 500 and 550k's to a tank. Cleaning the MAF made no difference to fuel economy in my truck and in regards to the speedo...strangly enough with the 32's the speedo is exactly spot on. I have tested my speed against several GPS units all of which match the dashboard needle.

^^^^^This goes for me too, even down to the speedo reading correct on 265's........

[TTR]

Im running ARB Sahara Bar, MR bash plates (heavy!) dual batts, DP Chip on the highest setting, 3" zorst and drive it like like I stole it pretty much all the time. Running 32" KM2 muddies and standard gearing, tyre pressure at 36psi cold in the front and 26 in the back, unloaded. I"m getting close to 600 from a tank. Average around town is 10.5 l/100k. Highway down to at least 9.

As box head said, try cleaning your MAF and MAP sensors. Maybe and injector clean on the next tank fill.

600 a tank is about 12.5l per 100 km - something which matches your mods almost to a tee

600 to the tank, IE when fuel light comes on I put fuel in and its 60 to 62 litres. How did you calculate 12.5l? 72 litre tank dead empty?

[StevenS]

Im running ARB Sahara Bar, MR bash plates (heavy!) dual batts, DP Chip on the highest setting, 3" zorst and drive it like like I stole it pretty much all the time. Running 32" KM2 muddies and standard gearing, tyre pressure at 36psi cold in the front and 26 in the back, unloaded. I"m getting close to 600 from a tank. Average around town is 10.5 l/100k. Highway down to at least 9.

As box head said, try cleaning your MAF and MAP sensors. Maybe and injector clean on the next tank fill.

600 a tank is about 12.5l per 100 km - something which matches your mods almost to a tee

600 to the tank, IE when fuel light comes on I put fuel in and its 60 to 62 litres. How did you calculate 12.5l? 72 litre tank dead empty?

Yes, it's a 75 Litres tank after all. My fuel light only comes on when I have roughly 5 litres left in the tank. I assumed you had an SR5 and were going off what the trip computer said as they inevitably read lower than actual.

If you are getting 10.5 per 100km at the pump with the above mods then I would assume you have a post mid-06 model with the newer computer? It's been my experience that despite having similar fuel claims from the factory, the mid-06 onwards models always seem to get 1-2Ls better economy then those with earlier models but similar mods may experience.

For example mines an 05 model single cab, with an aluminium tray but loaded to the gunnels with tools/compressors running on 265/75s and steel bull bar (no bashplates yet). I typically drive like a grandma and my economy has been getting worse, going from 11/100km about 2 months ago to around 12.2/100km now. Still can't figure out why despite new injectors, cleaned intake and sensors, new filters and fresh oil.

[TTR]

Yeah, mines a 2012 SR. Fuel light comes on and I only get 60 to 65 litres in it. Run it dry and I squeeze 70 in it.

[StevenS]

Ok now I'm definitely after some help guys from those in the know.

My 05 single cab's economy has been getting increasingly worse over the last 4 tanks (different servos but always one of the main ones).
The nearly the last 2 years my economy has been about 11L/100km no matter what I did.
With pretty much no chance in how I drive the ute or load on the back, the economy over the last 4 tanks was:
11.5
11.9
12.2
and just now when filled it worked out to 12.5L/100km.

its got new injectors and seats, cleaned intake and provent, new filters all around and fresh oil. MAP and MAF have been cleaned less than a month ago. It's got 190k on the clock.

What else could I check?

[dan9245]

My 2008 SR hilux d4d, is getting about 650km on the highway and about 550km around town, im running small tyres 225's and only have a steel bullbar and bash plates.... Revs higher hence more fuel consumption, i think the 265's would be optimum for fuel economy!

[GeeBung]

Yeah i just went from 265/75/16 to 245/75/16. Averaged about 12.5 on the 32"s and first tank on the 31"s 12.9.
Real unhappy with the result. Does sit in a better rev range at 100kph now though.

[Jasonsakr]

looks like its my injectors guys