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getting a constan read on MPG

Old Sep 23, 2005 | 09:07 PM
  #1  
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ramman16
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Default getting a constan read on MPG

hi on my 04 QC hemi the computer on the roof or whatever you call it only gives me an average of my MPG is there any way to make it give me a constant reading i know older rams had that function thanks
 
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Old Sep 23, 2005 | 09:23 PM
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Default RE: getting a constan read on MPG

Would be nice. I don't believe there's much one can do to achieve a real-time readout.
 
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Old Sep 23, 2005 | 10:55 PM
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Default RE: getting a constan read on MPG

The new computers don't have the constant or instantaneous MPG readout. Only the average since you have reset it last.
 
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Old Sep 24, 2005 | 01:14 AM
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Default RE: getting a constan read on MPG

EDIT.....sorry asked a Q then saw that i shouldve read more.
 
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Old Sep 24, 2005 | 08:23 AM
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Default RE: getting a constan read on MPG

Some people find this too much to do at the same time as driving,
but you can always find your 'instant' MPG over a stretch of highway
by watching how many miles it takes to use up one gallon of gasoline.

Press the button on the overhead trip computer until you get gallons.
Wait for the gallons to change to a new round number.
As the gallons changes,
Reach down and reset your 'trip miles' on the odometer.
Now wait and see how many miles it takes to burn one gallon of gasoline
(or another easy amount like 0.1 gallon, 10 gallons, etc)
If you go 18.1 miles during the time the gallons increases by 1
you got 18.1 MPG over that stretch of highway.

This is actually a more dependable measurement than the old
'instantaneous' MPG on the trip computer
which jumped around so much you couldn't trust it.
 
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Old Sep 26, 2005 | 04:10 PM
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Default RE: getting a constan read on MPG

I find that my computer is 1mpg high between fill ups. Take off slow and keep the rpm at 2k or under. Or take the lead out of your shoe!
 
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Old Sep 26, 2005 | 04:52 PM
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Default RE: getting a constan read on MPG

Since this seems to be little more than a computer moderated vacuum guage, you'd probably do just as well installing one of the latter, though it wouldn't give you mileage numbers. However, my experience with several "instantaneous" mpg readouts is that they are typically grossly overly optimistic, anyway.

All the best.
 
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Old Sep 27, 2005 | 04:15 AM
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Default RE: getting a constan read on MPG

some of the very first 3rd gen 1500 rams had the feature of being able to see real-time fuel mileage, i know my 02 ram had it, but my 04 currently does not. kinda wish it did, it was kinda nice to see what it was doin at a certain time.
 
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Old Sep 27, 2005 | 11:40 AM
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Default RE: getting a constan read on MPG

The "trip computer" doesn't have a flow sensor in the fuel system so it uses other, not sure what they are, means to figure MPG.
 
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Old Sep 28, 2005 | 11:35 AM
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Default RE: getting a constan read on MPG

The trip computer 'times' how long the fuel injectors squirt to find how many gallons are being used. This can be quite accurate, but will be off if the fuel pressure is either high or low.

It can also be off if deposits in the fuel injectors are clogging the spray (very common) or if the odometer is inaccurate (also common).

Maybe I am a cynic,
but nearly every Dodge vehicle I have test driven reads 5-10% high on miles right off the dealer lot - which falsely makes you think you are getting better MPG than you are, and also causes the warranty to run out sooner.

Mileposts should go by at a steady 60 mph in exactly 60 seconds.
At 72 mph the mileposts should go by every 50 seconds.
 
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