Novak Conversions Jeep Wrangler TJ radiator

TJ getting 5-6 mpg

Jpitty

Jpitty

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Original poster
Joined
Apr 23, 2021
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28
Location
Winnipeg, Manitoba
Ok so I'm getting 5-6 mpg this winter, I just bought this jeep last year and it's the first time I'm actually paying attention to the mileage.
Here's the catch since its minus 25-40 Celsius the last few months I've been Letting it idle for about 30 minutes total each day followed by 20 minutes of actual driving ..

Does this seem right?
 
You could have a bad O2 sensor. A bad sensor can erroneously indicate the fuel mixture is too rich. That would cause the PCM to eventually cause the fuel mixture to become full rich which will wreck the mpg and reduce performance too. If you replace them make sure you only use an NTK or NGK brand O2. Avoid both store brands and Bosch O2 sensors.

And a big welcome to WTF!
 
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Ok, ya once the weather warms up I'm not going to let run as much before driving it , o2 sensors I read the sticky post about them and will definitely go with the proper NTK or NGK brand O2, if I decide that route. I dont have any codes popping up , and engine seems to run pretty strong as well.

An example of a daily drive would be , start jeep for 15 minutes, drive to work 5 minutes, after work start Jeep for 15 minutes drive home or run some errands 5-10 minutes.. in winter with 4high on 75 percent of the time.

anything Else you recommend changing ? Fuel filter? Spark plugs ? The previous owner I believe changed the plugs before, no idea what brand, it has a new air filter.

Maybe just wait until summer and compare numbers ?

Thanks all!
 
If you're not moving, you're getting 0mpg, so...I wouldn't put too much thought into the overall mpg with that going on.

The prevailing wisdom these days is that cars don't need to warm up anymore (and in some places it's actually illegal to idle it if you're not sitting in it)...but I don't know how that applies to temperatures cold enough that it doesn't matter whether you're using C or F. Maybe get a block heater so your oil is good to flow in the morning, and save the idling for after work?
 
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pagrey said:
Wisdom is the wrong word for that.
Click to expand...

haha could be. I don't warm up but my rig rarely gets started up outside of my garage which never seems to get below about 45°F even on the coldest of days. I don't worry too much about that, but it seems like a different situation altogether when starting up an engine with oil that's within a few degrees of its pour point. I don't think I'd want to start that engine AT ALL without a block heater.
 
I use the block heater every day its colder then -20 , which is alot of days up here in Winnipeg, and 15 minutes is usually required to defog the front windshield and just enough time to get up to operating temperature, I'm only 5 minutes from work so I'd like it to be well ran to avoid other issues..
 
Jpitty said:
I use the block heater every day its colder then -20 , which is alot of days up here in Winnipeg, and 15 minutes is usually required to defog the front windshield and just enough time to get up to operating temperature, I'm only 5 minutes from work so I'd like it to be well ran to avoid other issues..
Click to expand...

I think you're just going to have to accept the fuel usage then, and check it again during the summer if you really want to know.
 
A car will use roughly 0.6L per hour per L of engine displacement, even more in cold temperatures. So that's 2.4L/her at the very least for you. To make things worse, you're not spending a lot of time at full operating temperature. The ECU runs the engine richer while it's warming up, which is quite a bit of time in your case. You're gonna have a lot of soot build up in your exhaust from it running rich, which will make your O2 sensors act all wonky.

I'd try giving it an Italian tune-up. Drive it hard for at least an hour, and see if that helps things before pulling your O2 sensors (let the exhaust cool down first). Going forwards, use your block heater more often. And maybe install an additional 120v heaters so the interior, and engine will warm up quicker. They're used a lot in the fleet trucks at the refineries I work at in Fort Mac, Edmonton, Regina, etc. since they don't do a lot of driving on the open road. They'll be plugged all into a 3-way extension cord.

https://www.canadiantire.ca/en/pdp/vehicle-interior-heater-110v-0303409p.html
https://www.canadiantire.ca/en/pdp/kat-s-200w-magnetic-heater-0303203p.html#srp
 
When you combine the idle time, the oil temps and 4wd I think it is very possible to see that low of mileage. All that cold oil is not easy to move.
 
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It is entirely possible that with those cold temps combined with the short drive time that the engine never warms up enough to get into closed loop. Are you running a winter front?
 
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Jezza said:
It is entirely possible that with those cold temps combined with the short drive time that the engine never warms up enough to get into closed loop. Are you running a winter front?
Click to expand...
No just stock front, I was thinking about putting a piece of cardboard in there this winter but decided not to, maybe try that next year...thanks
 
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