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Unread 03-10-2013, 07:34 PM   #16
outofrng623
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Which scan took are you using? By any chance do you have pid info?

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Unread 03-10-2013, 07:40 PM   #17
narnwv
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Quote:
Originally Posted by outofrng623 View Post
Driving highway it's around 160
That's way too cold.

Quote:
Originally Posted by outofrng623 View Post
Idle 203 f max.
Proper


How long while idling does it take to get to 203? What is the ambient temp?
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Unread 03-10-2013, 07:51 PM   #18
86cj74.2L
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My scan tool is a innova 3130 with abs upgrade.

Are you saying what you have will not show you live data?
image-3916575594.jpg  
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Unread 03-10-2013, 07:58 PM   #19
outofrng623
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I receive live data. Torque also has a non monitored systems test and I cannot find data on the specific tests. It's mode $06. The test ids are ids only, no description other than min max actual pass and fail.
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Unread 03-10-2013, 08:00 PM   #20
outofrng623
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I may be wrong on the 160. It was a while ago and this is off the top of my head...

It could also be that the app is reading something differently than it should. Ill watch dash gauge and scan gauge.

Anyway the obd would be showing different than the dash gauge?
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Unread 03-10-2013, 08:26 PM   #21
86cj74.2L
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Quote:
Originally Posted by outofrng623
Anyway the obd would be showing different than the dash gauge?
No, the dash gauge should mimic whatever info its receiving from the temp sensor on the engine.
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Unread 03-10-2013, 09:19 PM   #22
gsmullin
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Originally Posted by outofrng623 View Post
Thanks for looking, sorry for another mileage thread...I have been reading around for weeks and troubleshooting with no luck. Any ideas would be appreciated, hoping maybe someone has been through this.
Purchased an 04 JGC V8 in August, was getting around 13-15 MPG, calculated by hand. In November I started noticing I was filling up a little sooner than usual, so I started keeping track. Week after week I was losing approximately 1MPG. Now one week to the next, I can understand a fluctuation, but this is crazy. Winter gas cannot be that much different and as I mentioned this wasnt a dropoff from 13 to 6, this got worse over time...From 11/20 I was getting 9.8 and over the last 8 weeks or so I am getting under 8. Have gotten as low as 5.75 and that week I was intentually babying the car. I have had about 3 stalls over the last two months and the truck has started right back up. I have done the fuel reg/filter 2x, first one WIX pushed 62 PSI, switched to Mopar, kicks around 57psi now. Plugs (champions), air filter, TB cleaning, IAC (mopar), BARRS headgasket sealer due to a slight coolant smell and some smoke, it did help that situation...O2 sensors done (mopar). Gas cap is the original, had aftermarket for a while and put original back as I understand that could have caused some problem...truck has new rad cap, new thermostat...TPS checked by me, backprobed, analog meter, smooth as it should be...I have tried fuel system cleaners, different gas stations, one of those compression oil additives...I am out of ideas.
If an alternator or battery is acting up, but not failing, could that cause this much of a drop in MPG?
New battery terminal connectors...
NO CEL light (and yes it does work).
A deep scan using Torque shows a non-monitored sytem check, 2 precat O2s switch a little slow, but fuel trims should make up for that (fuel trims are never out of whack)...I have also received a failed test on the purge system monitor due to an IAC shift, but cannot find any real information on that.
Also, did a vac test, stays smooth and steady at 18, drops, pops up and steadies out when reved, as it should.
Truck runs great, its still fast, no misfires, no sputters, I get a slight hesitation if going to WOT, thats it.

Any ideas? Thanks
Do you see consistent results across multiple fuel stations & brands? Are you getting refill quantities that are consistent, assuming similar mileages at fill-ups?

mully
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Unread 03-10-2013, 09:50 PM   #23
86cj74.2L
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Quote:
Originally Posted by gsmullin

Not necessarily. Some OEMs utilize instrumentation algorithms to minimize display fluctuation despite variations in the actual inputs. Don't count on a 1:1 correspondence between display and actual. Thing of it as "averaging" with time delay....

mully
Yea, but its not going to be off by 20 degrees and their is only one sensor.
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Unread 03-11-2013, 04:18 AM   #24
outofrng623
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The fill ups, miles, etc are close enough +/- 10% week to week. Not enough to throw it off 5-8 miles per gallon. I've been tracking it since 11/20 and when I do a "fix" I fill back up and calculate any changes from that fix.

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Unread 03-11-2013, 06:40 AM   #25
outofrng623
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Being some have scan tools, thanks by the way...curious. What's your timing advance at idle? Intake pressure as well?

Thank
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Unread 03-11-2013, 06:56 AM   #26
PeteYJTJ
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If you suspected head gasket issues, have you done a compression test? Have you tried different octane levels, or is this all at low or high otane? How many miles on the motor?
Good luck,
Pete
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Unread 03-11-2013, 07:44 AM   #27
outofrng623
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Have not done a compression test, have tried different stations and different octane levels, 90% empty fills. No change worth noting.


Driving highway, 70ish
41 degrees f outside.
Intake temp ranged from 51-116
Coolant 192-205
Intake pressure 2.8-14.6

Thanks
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Unread 03-11-2013, 10:44 AM   #28
shepd
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With this type of mileage, I'd have a tailpipe emissions test done just to verify that it really is spewing gasoline. Because at 6 mpg you should be getting backfires like crazy.
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Unread 03-11-2013, 11:00 AM   #29
Wenatchee_Kid
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Would be interested to hear of any improvements after thermostat upgrade. Being 40 deg. low seems significant to your combustion.
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Unread 03-11-2013, 11:24 AM   #30
PeteYJTJ
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Quote:
Originally Posted by shepd View Post
With this type of mileage, I'd have a tailpipe emissions test done just to verify that it really is spewing gasoline. Because at 6 mpg you should be getting backfires like crazy.
That's a good idea -- I'd imagine you'd smell it pretty badly too, if you can't see the black smoke as well.

If your coolant is 192-205, I'd say that's pretty normal.
Pete
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