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Discussion Starter · #1 ·
Has anyone but me wondered about the relative accuracy of the gauges in the GT IUP? The fuel gauge goes up and down as expected, and the temp gauge starts low upon cold startup and rises to an expected mid-level as well. However, the volts and oil pressure don't fluctuate one bit once they've stabilized after startup. It's like the needles are painted on. Maybe this is OK, but I'd expect oil pressure to be higher when cold, and at higher RPM's. I'd also expect it to drop a bit when hot and at idle. Not the case. The needle doesn't move one iota regardless of temp or RPM. Voltmeter is the same. I'd expect it to fluctuate a little when turning on A/C or lights, and perhaps a bit lower at idle than at speed.

My question is: are these gauges telling me the truth, or are they just propped up to some arbitrary level by the computer to pacify me? Or, due to modern technology, are they able to control volts and oil pressure so finely that under normal conditions the levels don't change enough to see on a gauge? What's the dang deal here?
 

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O.P. guage works, watch it after an oil chang & you'll see it pump up. The guages are dampened just like the fuel guage and are slower to react. On/off on the rear defogger shows voltage change but engine mgmt. is smart enough to change rpm to compensate.

I guess all are setup not to alarm regular drivers vrs. the older guages erratic real-world swings (oil up/down when cold/hot - fuel guage up/down after hard turn - batt.guage low in bumper to bumper...)

Just glorified idiot lights, really. :rolleyes:
 

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The oil "pressure" gauge from the factory is pathetic. It operates via switch that will read fat dumb and happy with anything over like 5 or 6 PSI. If it were a real gauge, it would have numbers on it and it would fluctuate with engine speed and oil temp:rolleyes: Ford dampens it because they obviously think the average Mustang driver doesn't know how a real oil pressure gauge should work.
 

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blmpt said:
I recently discovered by speedometer is 4-5mph fast.
There was one of those roadside "this is how fast you are going" radars out last weekend. I made several passes at the exactly the speed limit. The radar consistently read that I was going 5-8 km/h under.
 

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I was curious about the accuracy of the information centers' # of gallons used feature. I finally tested it yesterday. The info center showed 7 gallons used. I topped off my tank at 7.155 gallons. Guess that answers that question! :smilie

As far as speed-o accuracy, I believe I read somewhere (don't ask me) that car manufacturers typically calibrate the speed-o to read 3-4 mph FASTER than your actual speed. I know this to be true on both our Explorers that have GPS installed. I haven't tested the Mustang yet, but I am sure it would have the same result. :wavey
 

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Discussion Starter · #7 ·
Andretti said:
Just glorified idiot lights, really. :rolleyes:
That's kinda what I was thinking. I'm not sorry I got the IUP, but I'm disappointed in these gauges. Sorry, but I wanta see 'em move!

Hadn't heard about the speedo inaccuracy before... I'll have to do the "count the mile markers" while doing 60 (1 mile per minute) and compare to elapsed time.

On this subject, if the speedo is off, is there a computer reflash that could fix it?
 

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Discussion Starter · #8 ·
2k5GTC said:
As far as speed-o accuracy, I believe I read somewhere (don't ask me) that car manufacturers typically calibrate the speed-o to read 3-4 mph FASTER than your actual speed. I know this to be true on both our Explorers that have GPS installed. I haven't tested the Mustang yet, but I am sure it would have the same result. :wavey
nonsensez9 said:
There was one of those roadside "this is how fast you are going" radars out last weekend. I made several passes at the exactly the speed limit. The radar consistently read that I was going 5-8 km/h under.
I have a '95 Dodge Intrepid which checks right on to those "this is your speed" thingies on the side of the road. Apparently, Dodge didn't calibrate their speedos high in '95. Can't say if all manufacturers do it now, or if Ford does and Dodge doesn't.
 

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I have an 05 GT and according to my GPS, the speedometer is "Dead on accurate up to 90 MPH." I didn't go faster then that with the GPS, but I would suspect if good up to 90, should be accurate all they way.
 

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the speedometer thing is not that they calibrate it to look like your going faster than you think.. rather its just that the sensors cant calculate exactly how fast your car is going. the average car's speedometer is off by about 1-5%. in the county i live in the cops have a policy to not pull you over until your doing 10 over because of this reason. as with the rest of the guages. they're factory gauges.... what do you expect. factory gauges are never designed to be 100% acurate, they are designed only to give you a good apraissal of whats going on with your car. for example tachometers are never correct unless you get an aftermarket one...

one last thing. on fords the oil pressure sender is only a ground source. when pressure is above about 5 psi it has a good ground and so the needle will read in the middle of the guage. below 5 psi it will drop to 0.
 
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