Still high fuel consumption after FULL SERVICE

[FATMOE]

The dash is always way off.

Use a fuel trip app on your phone.

I use road trip. But my dash reads between 16.2 - 17L

 

[Jonah 101]

Lol blocke exhaust? Ok - maybe but how can i know?

So you're taking the piss? Fine fix it yourself then.

 

[lout]

stop using E fuels they have much less calorific value than 91 octane
run to nearly empty then refuel with 91octane and recheck your economy
I think you will see a noticeable difference
with a stock engine we had a guy on hear a couple of years ago complaing about economy.
after weeks of suggestions he revealed he had modified his engine with camshaft, throttlebody, etc
does the temp gauge seem accurate?
any sort of flatspot or glitches with accelerator (thinking TPS maybe eratic)

 

[Clovance]

Fatmpe i did never say that i use my dash at all. So f*** the dash i do it with an phone app, too. And i explained how it works.

Jonah101 i dont know why youre in a pissy mood now. I just wanted to know how to check if the exhaust is blocked or not and laughed - thats it.

Lout i can try using another fuel, but then its more expensive. Do u really think it is worth to pay more but to come further? Have u already calculated if it is worth?

Ok but i havent modified anything at my engine. So everything is normal genuine.

Temp gauge seems correct, too. The first minutes driving it shows still cold and after a while it stops at about a quarter to a third but never a half or more.

Whats TPS or eratic? And how do i check that flatspots or glitches?

 

[Clutchy]

It could be the ethanol fuel like lout is getting at my old hilux use to drink heaps of fuel using the e crap use normal fuel and it was heaps better it might cost a bit more but if you get more Kay's out of it it really don't cost you more does it.

 

[lout]

E95 is 95 percent ethanol and 5 percent petrol
ethanol is about 60 percent the value of petrol
meaning petrol would be around 600km per tank, ethanol would be around 350km per tank
TPS is throttle position sensor, it acts the same as the accelerator pump on a carby
if TPS sees a large change in position it tells ECU to inject a large amount of fuel
such as if you floor it, if tps is worn it can be sending a faulty signal to ECU,
TPS usually starts causing hesitation in acceleration and eratic idle when worn.
I am fairly sure the ethanol fuel is your problem though.
91 octane should see you around 12L/100Km

 

[CONROD]

When you say your car is always loaded do you mean like this.

 

[Cheap6]

Loaded means about 200-300kg plus me all the time. And pls spare me your suggestion to put less in the car. I need all that stuff so it is not a solution.

That's enough to make a noticeable difference. The way to tell how much difference would be to remove it all and recheck the consumption over the same route(s). If you need it, well you just have to live with using some more fuel to lug it around.

What is EGR and TCC and how can i check them?

EGR is Exhaust Gas Recirculation. Check it by removing it and looking to see that it and the pipes that connect it to the inlet and exhaust manifolds are not blocked or sticking. It should set a fault code if it is sticking but might not if it blocked. It is located on the passenger side of the engine, towards the rear. You will probably need to replace the gasket if you remove the valve The fittings may be tight (WD40 or similar a few hours before removal helps a lot). Use carb. cleaner and a wire with a loop formed on the end to prevent damaging the pipe to scrape the crud out of the pipes.

TCC is Torque Converter Clutch (lock up). Watch for the rpm to drop in 4th gear at a steady cruise. The torque converter, between the engine and trans., is designed to allow some difference between engine speed and trans. speed, thus allowing the engine to idle, but it costs fuel if that still occurs when drive is required. The TCC lock up locks the engine and trans. together without slip between them when you are driving at a steady engine load and the slip is not required.

How can i check if my thermostat sensor is faulty or not?

Engine temp. check. If you have or will buy or borrow a digital multimeter you can measure the coolant temp. sensor resistance and relate that to the temp. it indicates. The values are in the 'How To' on switching a VN engine cooling fan along with the normal VT V6 operating temps and fan switch on temps., on here. There may be a way to access the coolant temp. through the instrument cluster but I don't know how to do it if you can. (I think I remember a post about it on here.)

drop your rear tyre pressure, that is a bit high, 34 all around is more than enough.

I'd say those pressures (38 R, 34 F) are OK. There is more load than normal over the rear wheels. Anything up to the max. pressure on the tyre sidewall is OK. I run 40psi, F + R, in my cars. The trade off is a slightly harsher ride but it's not teeth rattling.

Normally i use e95, sometimes e91.

You mean 91 or 95 octane. It won't be anything other than E0 or E10 (E85 would stop the car running).

The tyre pressure was too low with 36, because ive got so much stuff loaded it looked flat with 36, so i put it a bit higher. Should be fine...

Yep fine. (^)

Lol blocke exhaust? Ok - maybe but how can i know?

An easy check is to temporarily disconnect the exhaust and drive and see if there is a noticeable difference in performance with it disconnected. Wire the trailing part up. Sometimes a visual inspection can be useful. A blocked cat. converter can be seen if you shine a light through it and look form the other end. Loose baffles in mufflers you can usually hear with a shake of the exhaust.

Lout i can try using another fuel, but then its more expensive. Do u really think it is worth to pay more but to come further? Have u already calculated if it is worth it?

There's no harm in trying it but the difference isn't that great. The difference in energy content between E10 and E0 is <5%. There might be some advantage to using a higher octane fuel (so 95) depending on your particular engine but that difference isn't going to be a lot either.

Temp gauge seems correct, too. The first minutes driving it shows still cold and after a while it stops at about a quarter to a third but never a half or more.

Instrument cluster gauges are pretty general in what they indicate. The VT is better than earlier models but the better way is to measure as above.

Whats TPS or eratic? And how do i check that flatspots or glitches?

Throttle Position Sensor. Normally it's used by the engine computer (PCM) to, among other things, add fuel when the accelerator pedal is moved. (The extra air gets to the engine before it is measured by the airflow meter (MAF), so needs extra fuel outside of that related directly to that measured by the MAF sensor.) If it's worn the voltage it sends to the PCM can be random and the PCM will interpret that change in voltage as a change in pedal position and a need for the extra fuel.

You might notice it by the way in which the car accelerates (or doesn't) in response to a rapid change in throttle position. It can also be checked using a voltmeter (DMM again) connected across the output terminals of the TPS while the throttle is slowly opened and looking to see that the voltage doesn't drop suddenly in the middle of the throttle travel.

E95 is 95 percent ethanol and 5 percent petrol

It would be if you could buy it from a pump anywhere. The highest ethanol content fuel available anywhere in Australia is E85 and even that may not contain 85% ethanol. If you tried to run that in a VT it would stop running pretty quickly.

ethanol is about 60 percent the value of petrol

66% per litre but since you can only buy nominally petrol fuels with an ethanol concentration of 10% (or less) the difference in energy content between E0 and E10 is under 5%.

I am fairly sure the ethanol fuel is your problem though. 91 octane should see you around 12L/100Km

I doubt it.

I think the biggest reason for high consumption (so far) is the extra weight. A few hundred kg's is a noticeably large mass to be accelerating.

 

[CONROD]

Sorry for posting the pic,but I couldnt resist :hiding:

 

[Brett_jjj]

Try using 98 octane fuels for a few tanks, I can get bloody excellent fuel economy from my VSV6 on 98 octane fuels, especially around town. Because I can go further on 98 fuels, it works out about the same price as using 91 octane fuels.
Id also get the wheel alignment checked, as a bad alignment can cause excessive fuel usage and it always gets overlooked. Get the alignment set to the factory specs with both sides adjusted so theyre dead equal. Ive found this gives the best economy.
Driving fairly normally, I can get anywhere from 6 to 8 litres/100km on the highway and anywhere from 9 to 12 litres/100km around town (depending on if the A/C is on or not).
Lastly, the 3 ignition coils can cause excessive fuel usage when they get old, even if they still seem to be working ok. Ive found that these coils slowly lose their performance over time, and this eventually starts to effect fuel economy, cranking times etc. Stay away from cheap aftermarket coils, as these coils can also cause the vehicle to use more fuel, its best to only use genuine igniton coils if you want to get the best performance and the best economy possible.