Hello Gentlemen,

Can any of you answer the question of how do the speedometers work in the 92-96 Fords with an E4OD transmission. Is the speed set by the computer, a sensor, a gear in the transmission or what? My driving force is I want to change out my 90 MPH max gauge face with the lightning 120 MPH maximum face (white face gauge kit). I am not sure how to go about making sure the speedometer is working correctly when I make the switch. The other gauges are easy even the Tach can be adjusted with an external meter. But the speedometer is a different matter. Can any one give me a hint on where to begin... Help Please!

Mike
95 F350 Dually

 

You want to have a gauge in your F350 that goes to 120? Are you insane? That means you want to go that fast, in a 6-8k# vehical! Never mind the fact that its governed to 97 mph in the first place!

aiyy yai yai!
I say just get the white face gauge made for your truck...but ugh yah we wont talk about my ideas on white faced gauges in cars

1995 F-150XL SC/SB
http://members.sounddomain.com/blind
5-Star Rated F-150 (Big Stereo)

 

Well My friend... My truck can easily go 120... I have had it faster somewhere around 137 so far (under controlled conditions of course gg). May I assume you have never heard of chipping a vehicle to kill speed limiters. Next I could car less about the white faces (although I do think they are a bit easier to read) I just want a more accurate speedometer at high speeds. I am using my GPS now for anything over 75 MPH. The factory Speedo starts to loose accuracy about 74 or so and it is completely unusable over 85 MPH there is no more gauge left. Finally I will guarantee that you cannot find white faces or any face gauges for a factory 92-96 truck in any configuration except the lightning 120 MPH version, they are just not manufactures (yet I am working on it thought). Not I am sorry if I sound testy but I don't like to get a slam when I am honestly asking for information from those who are knowledgeable, If you don't have something nice to say stay quite!

Mike
95 F350 Dually

 

late models 80-96 mfi, have speed sensors mtd to tranny..this sends signals to to the emc and cruise control...when changing tire diameters, or gear ratios, the comp needs to be adjusted..costs about $100.00 at a dealership..mine was done when i went to 32's..tech said it was a calculation and was iffy to get it perfect, but he did well!

 

Thankx AIM.... I appreciate your help. I am in contact with Danny T. about doing an adjustment on my Superchip which will help I hope... Keep your fingers crossed.

Mike
95 F350 Dually

 

oh sham..good luck..and i guess you know how to align the chips..etc?

 

Align? I am not sure I know what you mean by that? I assume you me to make sure the chip is seated correctly and making good contact with the ECM terminals..... Would you mind explaining? Just incase it is something I am unaware of

Mike
95 F350 Dually

 

Mike, white gauge faces are available for ALL 92-00 F series trucks at Http://mustangsunlimited for $159.95 but if you want to calbrate yours to match the higher speed you can adjust it there is a post back farther with the calibration sequence for these trucks. John

 

If you change the calibration, the speedo will be right but the odometer will be wrong. Just something to consider. I hope that makes sense.


Garrett
[link:www.1966ford.com|1966ford.com]

 

Hey Forty.....

I checked the site you spoke of... (http://www.parts123.com/PartFrame.asp?ZTM=cadegfcc&GHOME=www.mustangsunlim ited.com&TITLE=Mustangs_Unlimited) is the link and like I thought all of the (white or any color) gauge faces for the old style gauges (92-96) are 120 MPH gauges... It is fairly easy to find the new style. The old ones are another story. I would live to read the post on calibration I am going to try a search as soon as I finish with this post. If you know where it is please let me know incase I cant find it.

Now what about the odometer being off.... I am confused about that one if the speedometer is calibrated to show the correct MPH then the odometer should be right on.... (I think...) Man I am beginning to wish I had not started this project. What a hassle! Oh well it will be nice to have better Speedo gauge.. Keep the posts coming gentlemen.

Mike
95 F350 Dually

 

Hey guys,

I found the post that FatForty (John) was refering to and I cut and pasted (with a bit of tweaking) it below.... Now all I need to do is figure the conversion constant to go frrom an 0-90 MPH readout to one with a 0-120 MPH readout... Ugh I should have paid more attention in math class... gg Thankx a bunch gentemen I needed this one!


Changing your gears will not affect you speedometer. Changing your tires (height) will throw off the Speedo. I used the following to recalibrate my Bronco with excellent results.

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.



Mike
95 F350 Dually

 

[font size="1" color="#FF0000"]LAST EDITED ON 11-Mar-01 AT 10:46 AM (EST)[/font][p]mike when i calibrated my spedo on my old truck the odometer was right on an mine was calibrated to 35 12.50 r15 tires i used the techniques john described in his earlier post but if you want to make sure your spedo is correct here is a easy little formula

mph =

rpm * wheel diameter (in inches)
-------------------- (divided by)
gear ratio * 336


hopes this helps in your troubles

 

If you're going to swap out the entire PSOM (programmable speedometer/odometer module) for one from a 95 Lightning, it will already be calibrated for the 30" tires that came stock on the lightning. I believe the 95 has the VSS (vehicle speed sensor) in the differential housing. If that is the case, the difference in rear end ratio will be automatically compensated, since the speed sensor reads output speed of the ring gear. If the VSS is in the tranny tailshaft housing, you will have to recalibrate accordingly. Beg, borrow or steal a Ford shop manual, all the information, including calibration conversion constants is in there. In the 96 shop manual, the calibration instructions are on page 13-01-27 and the table of constants is on page 13-01-45

 

OK guys,

I am making progress... The procedure above will move the speed.... But I need more adjustment than is available... The range allowed are from 500-1100 an I need a .75 constant which is about 1374... Not enough there.. I am guessing that StrangeRanger is getting close to theanswer with his statement... There must be a gear or "something???" in the RearEnd or in the Trans that I need to swap out with the one from a Lightning model... Then I can fine tune the Speedo with the electronic adjuster... Any thoughts gentlemen. Where-oh-where is the Speedo gear and how do I change it? Help!
Mike
95 F350 Dually

 

Start with basics. Where is the VSS located on a 95? Without knowing this we are all just guessing. If it is in the rear end like it is on a 96 THERE IS NO GEAR. The calibrations are internal to the module and you will need to replace the complete module, not just reface the gauge.

Look at your differential housing. If there is an electrical connection on the front of the housing above where the driveshaft connects to the rear u-joint, that is the VSS. If there is none there it should be on the right side of the transmission tailshaft housing. Let us know which you have.