LS1 tune

[Baldoldfart]

I have a VY Adventra that uses a fair bit of fuel, I had it tuned when I got it quite a few k's ago. The car had a mafless tune when I got it. After the tune the fuel use got down to under 11 L/100k's, now varies on use to average around 14/15L/100k's. I am not familiar with modern computer controlled fuel injected engines, more distributors and carbs. Does a modern motor loose it's tune? How often do you have to get tuned? Would a mafless tune effect fuel use derogatorily?

 

[Forcedvp]

Tune is fine. More a case that the computer is compensating for degrading components such as 02 sensors, exhaust, spark plugs, coils etc.

 

[07GTS]

tunes base dosnt change, fuel trims and the like do change just to keep the base fueling where its set, the only way fueling gets worse is if a sensor is failing or something is going on, even cooler weather will affect fuel usage, maf or mafless if both done right u wouldnt notice any difference between them

 

[Baldoldfart]

Thanks fellas

 

[vr304]

Probably fair to say the o2 sensors will need to be replaced if they’ve never been done in your ownership, they do go out over time and affect fuel economy

 

[Lex]

I have a VY Adventra that uses a fair bit of fuel, I had it tuned when I got it quite a few k's ago. The car had a mafless tune when I got it. After the tune the fuel use got down to under 11 L/100k's, now varies on use to average around 14/15L/100k's. I am not familiar with modern computer controlled fuel injected engines, more distributors and carbs. Does a modern motor loose it's tune? How often do you have to get tuned? Would a mafless tune effect fuel use derogatorily?

I've noticed with my vt v6. If only going to the shops, distance of about 6 km there & back, doing this average fuel usage will go up. It doesn't get up to closed loop mode. Engine temperature not getting very warm.

Take it out on the freeway, highway, the fuel usage comes down. When l fill the tank, l reset the trip distance, which resets the fuel trims, take for a short drive down the freeway, which will get the fuel trims down to 10 - 12 km per 100km very quick.
If l was to take it out on the freeway, without resetting the fuel trims, it would take 100's of km to get the trims down.

So what driving are you mostly doing, short trips to the shops or down the highway?

 

[Baldoldfart]

Never any less than 50 k's after startup. I used to reset the trip every tankful, haven't done that for a while. 15L/100 k's is about what I average now, that's easy on the throttle. Drops a bit more when I stick the boot in.

 

[Lex]

Never any less than 50 k's after startup.

100 kmh or 60 kmh?

 

[Baldoldfart]

Country driving usually around 80k's, then longer trips sitting on 100.

 

[Lex]

Country driving usually around 80k's, then longer trips sitting on 100.

Then probably what the other people have said?