Hi All, I have just got myself a tj series 2 vrx auto and I'm getting some wild readings. Set in instant fuel mode. In drive, pulling away the number will go up to 66/per 100 and just moving the acc pedal 10mm. Once up to speed things settle to 10-12/100. Reading the forum I changed the O2 and coolent sensor. Should I worried about the crazy numbers or is this a TJ thing. My TH 5 speed M never gives numbers like this unless Ii'm trying to push the acc through the floor. Regards Oldmag.

The instant read out is correct. Your car is behaving normally. It's simple mathematics.

My TL does this all the time. Perhaps in later models the sampling rate was increased.

If you drive in 5th gear at 60km/hr on a flat road, what is the instantaneous read out?

I'll check about 12/100 I think from memory.

At idle, stop/start, or getting upto speed from stationary your instantaneous readout will always be through the roof as, aside from wide open throttle or cold starts, this is when the A/F ratio is at its richest.
The more important aspect of the fuel economy readout would be average l/100km, driving under normal conditions over an extended period of time, as this gives a better indication of fuel economy in general.

Pretty normal readings on a TJ auto exec.
I can get 60 or so L/100 km just backing out the driveway with a cold engine, down to 7 or so on a long run at a steady 110 kph.

Doing 60 L/100 km for one km will use exactly .6L, so no problems really.

Wife's Lancer has an adjustable readout - L/100 km, miles per US gallon, miles per UK gallon - currently set to Miles per UK gallon (because I can). It resets after 4 hours of not using the car, so when you start the car it basically gives you an initial instantaneous MPG readout. Backing out cold = 1.5 MPG, 10 MPG after 50 meters (first corner), goes up quickly to 30 MPG on any drive more than 5 km even in city traffic.

Thanks for the feedback guys, very appreciated. Not worrying about the wild numbers and new sensors look to have settled my fuel usage to some degree. Regards oldmag.

At 60km/hr in 5th gear on a straight, level road you should be getting an instantaneous reading in the order of 6L/100km.

At 60km/hr in 5th gear on a straight, level road you should be getting an instantaneous reading in the order of 6L/100km.

Got the chance to test tonight on a flat section of road, 5th gear at 60kph= 5.7L 6.3L 5th at 100kph=7.6L,8.4L.

Sounds good, pretty much what I (can) get too.

Most of the high consumption comes from low speed driving, warming up the engine, stopping and accelerating, idling while at traffic lights, etc.