speedometer recalibration
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Senior Member
Joined: Oct 2004
Posts: 368
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From: East Texas
speedometer recalibration
I've got a 97 f150 4x4 that came with 245/75/16's stock. I am now running 285's and my speedo is now showing 58 mph when I am really doing 70. Can I use a power programmer to fix my problem or do I have to change the VSS gear? I am running a 4.6 / 4EOD with 3.55's if anyone who responds needs this info. Oh yeah, if I get the VSS gear, how many teeth does it need to have?
Member
Joined: Jul 2004
Posts: 24
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From: Rapid City, SD
On your '97 you need to change the speedo gear. Best way to determine the number of teeth you need is to give the dealer your original and current tire (and wheel if you're running something different now) sizes when you go buy the gear.
On your other post, you ought to get around 25 extra ponies with the high octane program, but it varies... Changing the shift points and shift firmness on your tranny will be a big plus too.
If you want more info, use the site's search feature. These are real common questions that everyone asks on their first visit to the forum, so they've been discussed many, many times before.
On your other post, you ought to get around 25 extra ponies with the high octane program, but it varies... Changing the shift points and shift firmness on your tranny will be a big plus too.
If you want more info, use the site's search feature. These are real common questions that everyone asks on their first visit to the forum, so they've been discussed many, many times before.
Former Sponsor
Joined: Mar 1998
Posts: 13,385
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From: Virginia
Hi japickar,
On all of the pre-1999 F-150's, you''ll have to change the speedo gear to recalibrate the speedometer, just as vehicles have done for decades - the "old-fashioned" way.
That cannot be done in the PCM program until the 1999 model year in the F-150.
Now just many teeth you'll need will depend on how far off the speedo actually is, and how many teeth are on your *original* gear - you'll have to know both of those factors so you can do the math to determine how many teeth are needed to correct it.
You can use the SEARCH feature here to retrieve any of our many previous posts here on how to calculate the number of teeth needed once you know how far it's off now, and how many teeth are on the current speedo gear. The icon to access the SEARCH feature here is in the upper right portion of your screen.
Good luck!
On all of the pre-1999 F-150's, you''ll have to change the speedo gear to recalibrate the speedometer, just as vehicles have done for decades - the "old-fashioned" way.
That cannot be done in the PCM program until the 1999 model year in the F-150. Now just many teeth you'll need will depend on how far off the speedo actually is, and how many teeth are on your *original* gear - you'll have to know both of those factors so you can do the math to determine how many teeth are needed to correct it.
You can use the SEARCH feature here to retrieve any of our many previous posts here on how to calculate the number of teeth needed once you know how far it's off now, and how many teeth are on the current speedo gear. The icon to access the SEARCH feature here is in the upper right portion of your screen.
Good luck!
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Senior Member
Joined: Oct 2004
Posts: 368
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From: East Texas
Changed out the gear and the speedo is almost perfect now. It took about 30 seconds to take the old gear out and another 30 to put it back in. The step that took the longest was convincing my "knowledgable" ford dealer that that was the part I needed, even after I showed them the old gear! They were bound and determined to hook my truck up to their diagnostic machine just to charge me 85 bucks for something that wouldn't have helped me at all! I guess I come here for my first opinion from now on. You guys saved me a lot of time and money.