I added larger tires and regeared so now obviously both are off. Wondering how to go about recalibrating it?
How do I recalibrate my speedometer and odometer?
- Thread starter Byoung7982
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First things first, a miscalibrated speedo is very much an indicator of a head gasket failing. It probably hasnt failed yet but I would give @beno a call and get a 'valve grind kit' on order. You can read about other things to fix while youre in there. Good luck. IdahoDoug used to have a dvd that can help.
- Thread starter
- #3
Guessing that is not it. The engine was completely rebuilt top and bottom about 10k ago. The speedo was off before that and off still. Again I am sure it is the tires and regearing. I know on the new Jeeps I just take it to the dealership and have them down load a software patch.
It's just one rabbit hole after another here
Tall joke
Yeah, the newer vehicles can repair the headgaskets with a software patch. Machine learning, data science. That sort of thing. But that's not supported on a vehicle manufactured before 2002 due to the IEEE 453.b standard that permitted electronic introspection. They had the technology but it wasn't DOT approved, pretty much.
Do a search for local shops where you live who do speed o calibration, they will have both the drive, and driven speed o gears needed to get your speed o reading correctly. The last time i had this done on a customers car, they had to crack the trans open to change out the drive gear on the output shaft, plus a new driven gear. If i remember correctly, the cost was around 125 bucks for parts and labor.
Ok so @nukegoat was just busting your ovaries about the speedo, I am sure you have one dem smart Phones there is an App that when you are driving it can tell you your speed, and then look at your speedo and see what it tells you, so like the app tells you you are going 55, but your speedo said 50, then you know about what the difference is, or you could go all @NLXTACY and go and find the exact diameter of your tires every day and then have a Ipad with a Ram mount to tell you by exactly the diameter of tire any given time
I use a laser range finder
Look up Yellowbox. It is a Speedo correction that plugs into your OBD2 port (or OBD1) and will correct the speedo as I understand it.
These are done by wire from the sensor on the transfer case to the speedo. No direct cables here.......
Official home page of the Yellow Box Speedo Recalibrator
These are done by wire from the sensor on the transfer case to the speedo. No direct cables here.......
Official home page of the Yellow Box Speedo Recalibrator
- Thread starter
- #13
This may be a dumb questions but if my Speedo is showing 10 mph faster than I am going am I correct in thinking that my odometer is putting on more miles than I am actually going?
Yes, but larger tires will have the opposite effect on your speedometer. So your Odo will read less than actual miles.
- Thread starter
- #15
That is what I would have figured but it has been reading 10 faster since I bought it.
However, if you mount a fan to the roof as well as a sail, you will increase your MPG by 162%. Your speedometer will read in a percentage difference in the rolling radius ratio of the tire you currently have VS the stock tire.
If you divide by 3, multiply by 7.939, then add 6. You will have the correct answer.
If you divide by 3, multiply by 7.939, then add 6. You will have the correct answer.
I 2nd this fix. Use it myself with fantastic results. Get the model that has the connectors already put on for your vehicle. I calibrated it to between 0-.5 mph difference from GPS (depending on speed).
Get a gps app and figure out what the difference is. I programmed my scanguage to show me my actual MPG. Mine turned out to be exactly 10% difference. I can do that in my fool head.
But I would go with the advice @nukegoat suggested. Seems pretty solid.
But I would go with the advice @nukegoat suggested. Seems pretty solid.
I didn’t calibrate anything because my Land Cruiser would never lie to me.