Speedometer ?
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Senior User
Joined: May 2011
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From: Garden City
Speedometer ?
I have an issue with my speedo that I'm not sure that resetting the psom will fix. My real speed, via speedo app on a phone, of 65 mph requires an indicated speed of 71/72. I had initially considered getting a little larger tire to correct this, but decided to see if the odometer is off before doing that.
Using the same app, I drove an indicated 20.1 miles, and the trip meter on the app indicated 20.03. This is not enough to warrant a tire change, and can be attributed to a worn tread depth vs. new. My question is this; Can the needle be repositioned on the speedometer, and how would it be done?
Using the same app, I drove an indicated 20.1 miles, and the trip meter on the app indicated 20.03. This is not enough to warrant a tire change, and can be attributed to a worn tread depth vs. new. My question is this; Can the needle be repositioned on the speedometer, and how would it be done?
i ain't rite
Joined: Mar 2005
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From: Marlboro Mental Hospital.
something is not correct. if the trip meter reads .07 of a mile low after 20 miles, the speedometer will not read 6 MPH high at 65 MPH
if the speedometer is 6 mph high at 60, the trip read 2 miles more than actual at 20 miles traveled.
if the speedometer is 6 mph high at 60, the trip read 2 miles more than actual at 20 miles traveled.
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
The below applies to your 1992 F150.
If the PSOM is driving the speedometer head needle wrong, too high or too low on the scale I would try a different PSOM or head to find the item causing the needle to be off.
Or better yet just replace the speedometer head and PSOM as a unit and copy your old mileage over to the PSOM that you are putting in.
No I do not know of any way to change what the needle points to with a set signal value from the PSOM. The needle should point to 30mph @ 667Hz going into the PSOM on the bench.
If the PSOM is driving the speedometer head needle wrong, too high or too low on the scale I would try a different PSOM or head to find the item causing the needle to be off.
Or better yet just replace the speedometer head and PSOM as a unit and copy your old mileage over to the PSOM that you are putting in.
No I do not know of any way to change what the needle points to with a set signal value from the PSOM. The needle should point to 30mph @ 667Hz going into the PSOM on the bench.
Fleet Owner
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From: Easton,Ks
Another speedometer head from a salvage yard. The PSOM just plugs onto the speedometer head.
Also make sure there is a peg just below zero so the speedometer head can calibrate itself each time the key is turned on. The needle should hit this peg when the key is first turned to on.
Also make sure there is a peg just below zero so the speedometer head can calibrate itself each time the key is turned on. The needle should hit this peg when the key is first turned to on.
Lead Driver
Joined: Mar 2006
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From: IL
Did you try recalibrating first?
HOW TO RECALIBRATE THE SPEEDOMETER ON 92-96 FORD F-SERIES AND BRONCO | Ford Trucks
HOW TO RECALIBRATE THE SPEEDOMETER ON 92-96 FORD F-SERIES AND BRONCO | Ford Trucks
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
Did you try recalibrating first?
HOW TO RECALIBRATE THE SPEEDOMETER ON 92-96 FORD F-SERIES AND BRONCO | Ford Trucks
HOW TO RECALIBRATE THE SPEEDOMETER ON 92-96 FORD F-SERIES AND BRONCO | Ford Trucks
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Fleet Owner
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From: Easton,Ks
I think you should get on a interstate highway and time the mile markers while holding the needle right on 60mph and see if the mile markers come up every 60 seconds.
Have someone with you for the timing for safety.
I do not trust the app on your phone for this testing.
Have someone with you for the timing for safety.
I do not trust the app on your phone for this testing.
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Lead Driver
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From: IL
I'm sorry, I guess I didn't read his post well enough. If he's using a phone APP to compare to his speedometer, wouldn't he be just as well off to have someone pace him to let him know his speed or use a Garmin GPS unit. I've used a few different GPS's traveling back and forth to FL from IL and they've been pretty accurate.
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I'm sorry, I guess I didn't read his post well enough. If he's using a phone APP to compare to his speedometer, wouldn't he be just as well off to have someone pace him to let him know his speed or use a Garmin GPS unit. I've used a few different GPS's traveling back and forth to FL from IL and they've been pretty accurate.
I hope you're able to get it figured out!
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From: Garden City
I think the phone app is accurate enough for my purposes. I've used it in a few different vehicles that I know have accurate readouts and the app reads the same as the car. It is just slow to adjust during accel/decel, but for steady speed it is just fine. I have checked my odometer to the mile markers over the years, and if that was bad I would have done something about it a long time ago.
There were other indications of my speedo reading fast. Things like being tailgated even at residential speeds. I just thought people were being rude or impatient. The other day, one of my co workers passed me in that "get out of my way" style. So I asked him if I was holding him up. He was like "Yeah, why is James going only 38? Come on, man! Move it!". My speedo was reading 42. We were in a 40 mph zone.
Thanks for the info on how the speedo works, and I'll see if I can get another unit to try. I assume that 92-96 are interchangeable? And can the speedo be changed out by itself? I've never had one of this generation apart.
There were other indications of my speedo reading fast. Things like being tailgated even at residential speeds. I just thought people were being rude or impatient. The other day, one of my co workers passed me in that "get out of my way" style. So I asked him if I was holding him up. He was like "Yeah, why is James going only 38? Come on, man! Move it!". My speedo was reading 42. We were in a 40 mph zone.
Thanks for the info on how the speedo works, and I'll see if I can get another unit to try. I assume that 92-96 are interchangeable? And can the speedo be changed out by itself? I've never had one of this generation apart.
Fleet Owner
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From: Easton,Ks
No the replacement speedometer head will plug right into your PSOM.
Yes, if the truck the combo was removed from has a different size tires then you will have to change the calibration as noted above in the link by Mike1.
You will also have the mileage that the truck it was removed from had unless your data is copied over from the EEPROM on your old PSOM to the EEPROM on the new board.
Any speedometer shop should be able to copy it or anybody with a EEPROM programer and a computer running XP. EEPROM programers do not cost much on ebay but you will need a USB port on your computer and a clip for the EEPROM for connection.
You will also have the mileage that the truck it was removed from had unless your data is copied over from the EEPROM on your old PSOM to the EEPROM on the new board.
Any speedometer shop should be able to copy it or anybody with a EEPROM programer and a computer running XP. EEPROM programers do not cost much on ebay but you will need a USB port on your computer and a clip for the EEPROM for connection.
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