[dreptroman]

Hey guys. I have observed lately an increase in fuel consumption. It is something like 15 20% more than it used to be.

I have recently changed the vacuum solenoids and AT fluid.

Sparks are 30.000 km old and no misfires.

What should I log for to see if it s burning more fuel than normally.

I am running MHD Stage 1 FMIC so there are no codes on O2 sensors as far as I know...how should I log for? Stft? Ltft? AFR?

[madmantwo]

Weigh your right foot, it has likely gotten heavier.

Also, idk if leaky injectors can cause noticeable increases in fuel consumption, but you can sometimes see evidence for leaky injectors by watching the AFRs after letting off the throttle. If it were that bad, though, you'd have misfires and rough idle

[dreptroman]

Does MHD log AFR? I can't seem to find it.

22.5L/100km is kind of a lot for city traffic )

[muncie21]

Originally Posted by dreptroman

Does MHD log AFR? I can't seem to find it.

22.5L/100km is kind of a lot for city traffic )

You can see both short and long fuel trims with MHD. I'd start by looking at those

[klipse]

Big Foot syndrome, lead poisoning, increased speed limit signs, etc.

[335e92tx]

AFR is lambda.

Plot throttle opening at steady state speed and AFR, with STFT. Should be flat lines. If not does it also vary at cold start?
If cold start is fine but variation comes into play after operating temp change front O2 sensors first. Especially if mileage is over 100K.

If the same problem also exists at cold start you probably have other issues. Missfires most likely. Its unlikely lean condition from a vacuum leak would significantly affect fuel consumption at steady state speed.