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Messages posted by: WXman
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Well I hand calculated that tank and it was 20.5 MPG.

I got to figuring up my tanks lately in my spreadsheet and after I accounted for the 1 MPH too fast that my speedo was on stock tires, and the 1 MPH too slow that it is now, the results were that post-tune I am now getting 0.0-0.5 MPG more than I was before. I think that this tank of fresh diesel from the truck stop will get me up a little higher still. I also did not add any anti-gel to this tank. I think that the tune may get back the mileage I lost with the AT tires which is a pretty good deal. For what it's worth, my EVIC was 2.0 MPG high at the end of the tank so it's not off as bad as some users have experienced.

Man...this cold weather is getting annoying.
Your load range E tires are going to be really hard on MPG numbers because A) "E" tires are meant for 1-ton trucks and are VERY heavy tires and B) they are taller than stock and put more leverage against the drivetrain. I stayed away from "E" rated tires on purpose. Going with a "P" or "SL" rated tire is much more suitable for the Jeep. However, my Grabber AT2 tires did not get good marks from CR in the rolling resistence dept...so my tires are not exactly helping my MPG figures either.

I went out last night and verified my odometer. It is in dead lock-step with the speedometer. GPS shows my speedo to be 1 MPH too fast at highway speed. So my odometer is only 2% off. It appears that this tank is going to end up around 20 MPG. But...the temp. is 6 degrees this morning. It's been a cold winter. I'm very hopeful that when Spring comes...I can get at least 25 MPG average. If I can do that, on these AT tires, I'll be very happy.
I put a full tube of this stuff down my tranny fill tube today and it didn't even phase the shudder. Should I try another tube or would that be bad for the tranny?
Dragging brakes... that is a possibility. I noticed that my right front caliper was leaking where the banjo bolt connects to the caliper. I replaced the caliper with a reman. unit and used all new hardware and greased the pins. I even installed new copper washers on both sides of the banjo bolt. The leak got better. I bled the brakes the old fashioned way.

Now, there are times with my Jeep will pull hard to the left under strong braking. Other times it's fine. The pedal also feels like it has more travel in it than it should. (My pads are all new). So I am very suspicious of my entire brake system right now. Perhaps it needs to be bled in a different manner since it has 4-wheel ABS??

In any case I will try to get some different brands of fuel and try them. I'll let you know what I find.

Otherwise the Jeep is running very good right now and I'm happy with the tune. Thanks.
GreenDieselEngineering wrote:WXman,

Is the CEL off? Any changes in starting the engine stock vs. tune? Were you using the additives pre-tune? Are the mileage figures hand calculated? and not EVIC as it has some accuracy issues on most KJs. Have you noticed an improvement in city driving, launching and passing? Hopefully the mpgs will increase for you, the extreme cold will rob a few %, but nowhere near where you are running. What driving mix is typical for your KJ, city/highway?

Thanks for the feedback.

Yes, CEL is off. I use block heater when temp. hits 15°F or below. Engine starts fine, spikes to 1,000 RPM immediately, then idles normal. I do hand calculate my mileage and use EVIC too. Pre-tune my EVIC was always very accurate. I still haven't gotten a good feel for how close it is post-tune.

My driving is 50/50 city and highway. I have a 15 mile commute to work, most of which is 55 MPH. I drive very conservatively. Right now I have 250 miles on this tank...and I'm at the tick above 1/4 tank mark. Not looking good at all.

Running synthetic oil, new filters everywhere, clean MAP sensor, 35 PSI in the tires, only run defrost when I need it. Other than the quality of fuel...I don't know what else could be causing this horrible economy.

As far as power, yeah it feels a little stronger but not what I expected 65 lb./ft. to feel like. Maybe my TC and/or pump is holding me back? The engine is very quiet now. Even pulling up a hill at 2 MPH it's very quiet whereas before it sounded like a tractor.
So far the only place I have been fueling up is Murphy USA (Walmart). They have a sticker on the pump that says "guaranteed not to gel to minus 20 degrees". Holy cow that's hard to believe so I put anti-gel additive in anyway. So Friday I'm going to hit a Flying J truck stop for some good diesel and I won't use any additives so I can see if the Walmart fuel and/or additive is my problem. I bet if I use good fuel with no additive I'll see better numbers. When the weather finally breaks it'll surely help too. Right now I'm just disappointed.
So where exactly are you guys buying this additive? Any guesses on long term negative effects it could possibly have?
My MPG figures have been very low lately. I'm lucky to get 20 MPG. This is a 50/50 mix of city/highway and driving very conservatively. In fact, this current tank looks like it'll work out to around 18 MPG. That's pretty horrible for a vehicle like this. I'm wondering what affect using anti-gel additives has on fuel economy. Have you guys done any testing on this? The other thing that could be hurting me is that the temp. has been staying below freezing quite a bit lately. It's been a cold Winter here relative to average.
I'm going to miss my EVIC. I use it a lot.

Edit: With the GDE tune, my EVIC seems to be anywhere from 2 to 4 MPG optomistic at the end of a tank so far.
I plan to keep my EHM hooked up when I get my GDE ECU back. Reason why is because I don't want oil in my MAF sensor OR my intercooler, both of which are expensive parts.
I think the thermostats on the CRD are actually made into the bracket so you have to buy the whole assembly, right?
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