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-   -   8.7 MPG After TB / CAI install??!? (http://www.jeepgarage.org/f181/8-7-mpg-after-tb-cai-install-43950.html)

mcalc55 06-27-2012 11:53 AM

8.7 MPG After TB / CAI install??!?
 
Hey guys - had a FR TB installed by the shop and then installed an Airaid CAI myself and fairly confident everything went smoothly. I've checked the connections and everything seems secure and tight there but ever since then I've been registering almost a constant 8.7 MPG on the digital readout that fluctuates sometimes between 8.8 and 8.6 MPG. I've just gone and filled up so I'll be able to do a manual calculation to see if that's accurate or not but it's a little concerning. Just to confirm as well, this reading isn't one of those 'instant MPGs" right? It's intended to calculate long term MPG? ( I Can't remember off the top of my head cause it was disconnected from the CANBUS and only recently reconnected).

Also, its a 3.7 2006 WK

mTBrunner83 06-27-2012 11:59 AM

Re: 8.7 MPG After TB / CAI install??!?
 
I am pretty sure you should be seeing a vast difference between flooring it and coasting. I don't have my TB yet, but i got the tune and the CAI and I noticed a fluctuation from 6.4 mpg (flooring it) To 18.8 mpg coasting. I guess the real question is... how agressive are you driving?

mcalc55 06-27-2012 12:04 PM

Re: 8.7 MPG After TB / CAI install??!?
 
I've been super conservative now once i got the info system hooked back up and saw it , so is it an Instant MPG calculator? right now i dont see any difference when I let off the gas

mTBrunner83 06-27-2012 12:09 PM

Re: 8.7 MPG After TB / CAI install??!?
 
It appears to be an average of total miles travelled since reset. So from the start it should jump around. Eventually it will average out and stay around that. So I would say it is an instant calculator but not a solid way of knowing your MPG's until you put a couple hundred miles into it.

SvenskaJeepGuy 06-27-2012 12:39 PM

Re: 8.7 MPG After TB / CAI install??!?
 
the WK mpg computer calculates the average over the last 30 miles or since the last reset (which ever is sooner)

mcalc55 06-27-2012 01:12 PM

Re: 8.7 MPG After TB / CAI install??!?
 
oh wow, that's interesting - so if I reset prior to a long trip (say 500+ miles) and wanted to get an MPG over the highway I'd really only be getting the last 30 miles?...hmm

Good to know though, I'm doing almost all city driving though under 50 MPH (which might constitute aggressive) but 8.7 seems even worse than I'd imagined. I would assume it would be somewhere around 12 or 13...i suppose I should just hang tight and give it a few tanks and do the calculation manually, unfortunately for this (fortunately for my wallet) I walk to work so it takes me a few weeks to need a fill up.

SvenskaJeepGuy 06-27-2012 01:26 PM

Re: 8.7 MPG After TB / CAI install??!?
 
sometimes i go a few weeks with only city driving and i never get below 11-12mpg

2005JGC 06-27-2012 02:51 PM

Re: 8.7 MPG After TB / CAI install??!?
 
Also consider that the CIA really only sings at heavy throttle application, there may be a bit of subconsious heavier acceleration to hear your money at work ;)

mTBrunner83 06-27-2012 02:55 PM

Re: 8.7 MPG After TB / CAI install??!?
 
Quote:

Originally Posted by 2005JGC (Post 648895)
Also consider that the CIA really only sings at heavy throttle application, there may be a bit of subconsious heavier acceleration to hear your money at work ;)

I have a flowmaster delta 44 muffler and I can't hear it sing :( . But the drone makes me conservative on the pedal. So a win for the drone...

mcalc55 06-27-2012 04:56 PM

Re: 8.7 MPG After TB / CAI install??!?
 
haha thanks for all the input guys, sound like it's just me listening to my money at work - one last question, from a mechanical perspective, there's only two things I can think of; either the air sensor isn't working - which I assume it is since the check engine light hasn't come on, or there is some sort of 'leak' - which i don't think there is either because each end of the tube is secure and tight. Other than that the CAI is so simple I can't imagine its anything else.

I do have a pre-filter over it, would that make any difference?

mTBrunner83 06-27-2012 05:19 PM

Re: 8.7 MPG After TB / CAI install??!?
 
A prefilter will make a difference, but not that much. If the air sensor had an issue your PCM would throw a code. Unless you are offroading all the time I wouldn't use a pre-filter. Can't imagine you have a lot of dust and sand on the tarmac in NC.

mTBrunner83 06-27-2012 05:25 PM

Re: 8.7 MPG After TB / CAI install??!?
 
maybe since you are driving conservatively you should reset it. I am not sure about the 30 mile deal. Because to me it would seem that after 30 miles of travel your mpg's would remain unchanged until another 30 miles and so on. Maybe I am not understanding, but my mileage changes a few times every trip up and down which is only 14 miles, until after 300 miles I would gather. That is how I was seeing it anyhow.


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