So no special little computer tools required correct?

 

nope. Just any wire to ground out the PSOM module. It's very easy to do. I have changed mine following the same procedure. It takes 5 minutes.

Hope this helps!
Mike

 

Okay, so I checked the the CAL number and it was 8.09, my recommended CAL number is 8.25, there is not a very large difference in the numbers but what I am wondering is that even though it is small, is that still bad? Could that small amount be what is causing my transmission to "stick" when I am shifting? Thanks in advance.

 

If you have an E4OD.... you need the calibration to be correct fior the transmission to work properly.

Recalibrate your PSOM.

Good Luck,
Mike

 

What is the PSOM?

I thought I just needed to recalibrate the speedo.

 

Do I need to do the same to my '90 ??? 351w, same trans, 32" bfg tires... " that dont actually measure 32" remember ?" the door sticker says 31" tires-

 

<TABLE><TBODY><TR><TD vAlign=top width="100%">To confirm everything, if you can find an Interstate where you will not get run over, put it on 60 mph and look at your odometer when you pass a mile marker. Drive it for 10 miles and see if the odometer moved exactly 10 miles. In the process, time your miles with your watch. Of course, it should take you 60 seconds to travel the mile or exactly 10 minutes for the ten miles. That will test both your speedometer and odometer. Make notes as soon as you stop and if you have a lake model your can recalibrate if needed with just a jumper wire and your notes.
</TD></TR></TBODY></TABLE>

 

OK guys lets make it simple. I copied this from a 2005 post of mine.

If your odometer is digital and you have a little connection below the glove box this might help.....

High teck tools needed...wire, pencil, paper, calculator, and a mile marker sign of some kind.

A huge thanks for the thread somewhere that recommended the following site to correct the speedometer!

http://www.broncodata.com/tech/speedcor.htm

Correcting the speedometer and odometer costs nothing and was easy. I think he said this works for 92-96 models. Mine is a 94.

I have been wondering if a small bulb should be in the connection under the glovebox. Like the guy who suggested this method I ran a wire from that connector to the battery negative post.

I did the first paragraph and saw the reading "E 08 6" which means I can change it six times in the life of the vehicle. Then hit Reset again and read "918 CAL" which meant my conversion constant was currently 9.18.

Next checked tire pressure and drove the Interstate and kept changing my speed control until I traveled a mile every 60 seconds. I found I had to set it on 66 to go 60 MPH.

Back at the house I hooked up the wire from under glove box to battery ground. Got out a calculator and found 66 MPH divided by 60 MPH is 1.10. Multiply my 9.18 from my reading by 1.10 and and got 10.098 so rounded it to 10.10 which means the new conversion constant should be "1010 CAL" for my situation. You will have to adjust for your situation.

The instructions say the "CAL" will flash after you hook up the wire as in the second paragraph. Mine did not. After messing with the wire forever I punched Select and it started flashing. Then it took a lot of button pushing to go from 918 down to 500 then it jumps to 1100 and I stopped at 1010.

Took another reading and saw E 08 5 which means I can adjust it 5 more times if needed.

Back on the Interstate I set the speed control on 60MPH and ran PERFECT 60 second miles for 10 miles.

S u W h e a t. What a deal!!!!!!

The odometer reading remains the same at 168K but now I know it only has 153K actual because this is the first time it has been recalibrated.

AND, the transmission shift points are better. It was upshifting too soon and the next gear was sluggish, lugging the engine, until revs creaped up a little. Now it is perfect my my style of driving. I think I'll try for 400K as it just keeps getting better.

 

go to your tire manufacturers website and find out what the actual height of the tire is and how many revs per mile it will do then use this calc to get the proper psom setting
http://www.arkansasmud.com/psomcalc.html
also check out this post
http://fullsizebronco.com/forum/showthread.php?t=55005
has lots of info, good instructions and diagrams on where to find stuff.

 

Listen to Kem.

No need to guess and check settings if you get the correct revs/mile constant from your tire manufacturer.

Your calibration constant will be correctly calculated and speedometer/shift points accurate.


Regards,
Mike

 

I can't figure out my GVWR I need to know that for some reason?

 

did you go to the links i posted and read everything.