Fuel economy?

[HamishW96]

As per title.. what do people get fuel economy wise? My XJ has a clean intake, good plugs, wires, cap and rotor, all new fluids, no dragging brakes, clean filters and 28" tyres. I can't get below 18/100 on the freeway. I do have an 82deg tstat but I don't believe this is an issue after reading on the FSM that it should be fine.... I'm to be proven wrong. O2 sensor is original, I wanna change that... Could a bad coil cause shit economy? I have been grnadmaing it and can't get more than like 300km outta 60l fwy and a bit of round town.

[Classic Boy]

That is awful fuel economy. For example on a 6cyl WG grandie in my family that regularly tows a horse float the average indicated fuel economy is around 11.6L/Km mixed driving but that is with more country highways Kms than suburban trips.
At sometimes of the year show season when its tows a lot, almost every day with the float it will climb to 14.4L/100kms but once it goes back to general commuting it returns to below 12L/100km.
I installed a new genuine mopar O2 sensor about 18mths ago and it cut the average consumption sharply. The car is approaching 330,000kms.

I used genuine because O2 sensor because I read in a number of threads on a US jeep forum it was claimed the original mopar sensors gave better results than copies. I purchased it by part number from the US for around $60 to my door and it paid for itself in a couple of tankfuls.

[HamishW96]

Originally Posted by Classic Boy

That is awful fuel economy. For example on a 6cyl WG grandie in my family that regularly tows a horse float the average indicated fuel economy is around 11.6L/Km mixed driving but that is with more country highways Kms than suburban trips.
At sometimes of the year show season when its tows a lot, almost every day with the float it will climb to 14.4L/100kms but once it goes back to general commuting it returns to below 12L/100km.
I installed a new genuine mopar O2 sensor about 18mths ago and it cut the average consumption sharply. The car is approaching 330,000kms.

I used genuine because O2 sensor because I read in a number of threads on a US jeep forum it was claimed the original mopar sensors gave better results than copies. I purchased it by part number from the US for around $60 to my door and it paid for itself in a couple of tankfuls.

You reckon go a new 02 sensor? Mine is original. My car runs well, is quick etc but has a very sooty exhaust pipe lol and crackles like crazy when revved. I try to drive efficiently but its insane how bad the economy is....

The car is running at 82deg thermostat an issue? Seems like thats not overly an issue as I have heard the xj goes into its normal loop at 77degrees....

[aaronm]

my 1999 xj with 235000 klm. Tyres 235/75/15( 29 ) gets between 10.9 to 11.2 on the original injectors, strangley I replaced them 3 weeks ago with ford 4 hole injectors and its currently getting 11.2 to 11.4.but the throttle response is awesome

[HamishW96]

Originally Posted by aaronm

my 1999 xj with 235000 klm. Tyres 235/75/15( 29 ) gets between 10.9 to 11.2 on the original injectors, strangley I replaced them 3 weeks ago with ford 4 hole injectors and its currently getting 11.2 to 11.4.but the throttle response is awesome

Ah crap What temp thermostat is everyone running? My jeep has 150000klm on it so its a youngin.....

[HamishW96]

Hmmm I had a read about the o2 sensor fuse being a problem potentially, is this applicable for 95's? and if so where is it in the power distribution centre?

[Classic Boy]

The hotter the coolant temperature (within reason) the better for fuel economy and also engine life.
Our Grandies thermostat is stock 91C
I have and old chart printed in a engine manual in my workshop that shows the results of engine durability testing from the early 70's and it plots engine life against coolant temperature and the lower the coolant temperature the quicker the internal wear. The wear was found in lower coolant temps to be in a magnitude of many times.