I just installed 32" tires on my 1996 F150. The speedometer seems to be about 5 MPH slow. I have heard that the computer can be reset by Ford to adjust for different size tires.

Has anyone done this and what should it cost to have done?

shotgun

 

I had mine recalibrated at a ford dealer in Las Vegas and it cost me $66.00.

Kevin
94 F-150, 300, 2WD 2" body lift, 4" Susp lift, 33" tires

 

There is a very simple method for recalibrating your speedo. Do a search for "speedo" on this board and it will come up in one of the posts in the search results. Very simple did it myself for my 31X10.50's and it cost me $0.00

 

Here ya go shotgun...I cut and pasted for ya:

Just one word of caution the module can only be programmed 6 times

1. Locate the dealer mode programming enable single-terminal connector. The connector is located at the bottom of the instrument panel below the center of the glove box. On all vehicles, the dealer mode enable wire is Circuit 567(LB/Y).

2. Insert a jumper wire or alligator clip in service wire and clip other end to vehicle ground with the key in the OFF position.

3. Turn key to RUN while holding down the trip odometer RESET button on the speedometer.

4. Release RESET button The Speedometer will prove out(sweep across dial and back). The English/Metric and revision levels will be displayed. The last number of the display id the dealer mode lockout count. This count shows the number of allowable conversion constant changes remaining. When the count is zero (0), no additional changes can be made to this instrument cluster. If a revisionis required a service instrument cluster must be ordered.

5. Press and release RESET button again and PSOM conversion constant without the decimal point will be displayed followed by the word CAL.

6. The new conversion constant necessary to correct the speedometer can be found by determining the current percentage error. One way to do this is by comparing the indicated miles versus mile markers on an interstate trip. The longer the trip, the better indication of the error since interstate mile markers are not always exactly 1 mile but the average is very close to 1 mile. Going to taller tires (indicated miles less than true miles) will mean the conversion constant must be reduced by the same percentage as the speedometer error and going to smaller tires (or a numerically higher rear end ratio) means the conversion constant must be increased.

7. Press and release the odometer SELECT button as many times as necessary to change the conversion constant to the correct value. The constant will only increase (not decrease) when the SELECT button is pressed so reducing the constant means counting up until the constant jumps to the bottom of the scale and begins counting up from there.

8. Pressing and releasing the RESET button to lock in the new conversion constant reduces the number of times the PSOM can be reprogrammed by one count. If you change your mind and want to go back to the old conversion constant, turn the key OFF BEFORE you lock in the new constant.

9. Turn the key OFF and disconnect the ground wire and check to see that the speedo works correctly.

 

Recalibrate as said in the previous posts. The calibration constant for 32's is 8.86. You get this by multiplying .0135 by the number of revs/mile of your tire size. The revs/mile can be found on your tire web site, although all brands will be very similiar. The 8.86 is for a BFG All Terrain, but if you have a different brand you can do your own math if you want to get totally exact. Good luck, Ben

 

Kevin (crandall),

Do you have a pic of your '94 F-150? I, too, have a '94 f-150 2WD and want to basically make similar modifications, but want to see what the end result looks like. I figure I might start with the 2" body lift and go from there.

Thanks,
Cragar

 

Niteowl 17, beratte

Thanks for all the information. I will give it a try this weekend...

shotgun

 

Superlift's makes a speedo calibration sensor that, as far as i know, goes down on the speedo cable and can be recalibrated numerous times. That sensor also has two different settings on it. If you run one set of tires in the summer and a different set in the winter, you can calibrate it for both and it will work.
-Shawn-
1988 F-150 4x4 302 M5OD(Jap Crap tranny)
P.S.- Superlift's website is, www.superlift.com

 

[updated:LAST EDITED ON 31-Jul-02 AT 08:28 AM (EST)]I have a 96 ford extended cab 2wd with a 302. I want to go to a bigger tire with more aggressive tread to drive on sometimes wet sloped dirt road. I was thinking of the 31x 10.5 or 30x9.5.

I haul tools and materials often. Should I consider raising the body if so how? will this affect the stability and power of the vehicle and what kind of tires and or lifts should I get?

 

31/10.5/15 will fit on your 2wd. I would suggest a BFG all terrain for light of road use.


Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster American Thunder Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

Check out my Gallery for a look-see.


Then theres:
99' Mustang GT 4.6L
88' F-250 Superduty 4x4 351/c6
95' Mercury Cougar 4.6L V-8
80' E-350 300/6 with a
3 spd column shifter. Top speed is 65mph, Go Baby Go!

 

You can also get it from the tech articles on this site...

 

Here's the way simple aproach Real non-tech.Having lived in every 1 horse town in the southwest.I could not find a shop that would recalibrate my speedo,but did find a sheriff sitting beside the road on break.Told him when I flash my headlights at you hit me with the gun,I then knew within the laws perspective how much i was off. Find out exactly how off the speedo is.then go to ford dealer tell him how off it is,ask for the gear that goes on the end of the cable down on the tranny,made of plastic about 14.00.I was told each tooth on the gear is about 2 0r 3 mph.1989 f150 going from 29 inch stock firestones purchased new from factory to 33inch bfgoodrich atx.
Hope this helped,Billy..

 

Billy, he has a 96 where it is all electronic. Very simple to recalibrate. The 91- used cables and a plastic gear on the granny. The 92-96 like he has, uses a signal off the rear end excitor ring, all electronic.

Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster American Thunder Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

Check out my Gallery for a look-see.

Then theres:
99' Mustang GT 4.6L
88' F-250 Heavyduty 4x4 351/c6
95' Mercury Cougar 4.6L V-8
80' E-350 300/6 with a
3 spd column shifter. Weighs around 7,000lbs w. 65mph top speed, who wants to race me!

 

 

Hey nietowl7,

I want to do a similar with my 95F150 speedo. It has 30X9.5--R15 on it and I just want to check if the speedo is calibrated right. Can I go through the sequence without reducing the number 6 if I don't change anything. Also once I have my R.P.M.'s of the tire do you always use the0.135 multiplier?? Thanks