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Tach is reading wrong?

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Old Apr 7, 2017, 05:41 PM
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Tach is reading wrong?

So always thought my evo idles high at 1200 rpms. Well took it in for an evap code and turned out while the tach shows 1200 the car is at 850 rpms. Anyone ever heard of this? Know what I should look for?
Old Apr 7, 2017, 06:18 PM
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Originally Posted by Matthew Yonke
So always thought my evo idles high at 1200 rpms. Well took it in for an evap code and turned out while the tach shows 1200 the car is at 850 rpms. Anyone ever heard of this? Know what I should look for?
How do you know its idling at 850
Old Apr 7, 2017, 06:23 PM
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I have a OBD2 scan tool that gives live readouts of the ECU. It showed the motor idling at 850 rpm. Shows everything from throttle position, rpm, speed, etc
Old Apr 7, 2017, 06:27 PM
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Originally Posted by Matthew Yonke
I have a OBD2 scan tool that gives live readouts of the ECU. It showed the motor idling at 850 rpm. Shows everything from throttle position, rpm, speed, etc
I want to say check the gears on the cluster
Old Apr 7, 2017, 10:57 PM
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There used to be an overlay for the gauge cluster. To install it you had to pull off all of the pointers. I always wondered how people got then back on indicating correctly. Maybe you car had this once or maybe for some other reason someone was in there.
Old Apr 7, 2017, 11:01 PM
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Originally Posted by barneyb
There used to be an overlay for the gauge cluster. To install it you had to pull off all of the pointers. I always wondered how people got then back on indicating correctly. Maybe you car had this once or maybe for some other reason someone was in there.
Are you saying that the pointer is correct but the face of the gauge cluster is messed up? Not sure I am reading that right. Kinda weird what could be wrong if the computer is reading 850 rpms but the cluster is showing 1200.
Old Apr 7, 2017, 11:31 PM
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The needle just needs repositioning.
Old Apr 8, 2017, 08:39 AM
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Originally Posted by RightSaid fred
The needle just needs repositioning.
you know of any guide on how to do that?
Old Apr 8, 2017, 09:12 AM
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Black cat overlays are really cool looking but I've always worried that you have to pry (with a fork) the needles off, take off the OE overlays and put the aftermarket ones, then try to get the tach speedo, gas, and temp to read correctly. It's just a matter of pulling off the needles, reading the ODB 2 and then place the needles back on accordingly.
Old Apr 8, 2017, 09:13 PM
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Lift it over the stopper pin and take note of where the needle ends up.
That's before the first time it's taken off.
Then when you put it back on it ends up in the correct position.
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