speedcal issue - help needed!

98SVTContour98

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I had 4.30s installed last week and am trying to correct the speedometer and odometer...so i bought the following speedcal:

https://lmr.com/item/M4209ADPTAC/94-10-Mustang-Speed-Dial-Speedometer-Adjuster-M-4209AD

The mechanic installed it and put the 3 dials inside the box to 760 (based on this installation sheet - we used method 1 on page 8, which says to take the 3.27 divided by 4.30 which equals .760): http://latemodel.cachefly.net/downloads/instructions/M4209ADPTAC.pdf

The speedometer currently read like 80mph when the GPS says 20mph.

Any recommendations would be GREATLY appreciated.
 

98SVTContour98

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so after a loooooooooong process of elimination, looks like it finally might be figured out.

I set the speedcal, and then disconnected the battery for 30 minutes, connected everything back up, and it was within 2mph of the GPS. So I made a small adjustment to the dials and am waiting another 30 minutes to try it again.

So the entire problem may have been that we didn't clear the speedcal by disconnecting the battery.
 

98SVTContour98

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so after getting a new speedcal in from LMR, everything began to work correctly.

A week or so goes by and the speedometer and odometer go out, and the car begins to stall when coming to a stop with the car in neutral (which it had never done before).

Here's what I've done so far to attempt to remedy the problem:

*Reset the speedcal by disconnecting the battery and setting the speedcal to 000.
*Replace the VSS Sensor and VSS Connector cables.

I'm not sure what else to do. Could it be possible that another spoeedcal went bad?
 

jgt58

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so after getting a new speedcal in from LMR, everything began to work correctly.

A week or so goes by and the speedometer and odometer go out, and the car begins to stall when coming to a stop with the car in neutral (which it had never done before).

Here's what I've done so far to attempt to remedy the problem:

*Reset the speedcal by disconnecting the battery and setting the speedcal to 000.
*Replace the VSS Sensor and VSS Connector cables.

I'm not sure what else to do. Could it be possible that another spoeedcal went bad?
Had the same issue. Your new wiring is grounding out somewhere. Those speed cals take awhile to figure out the correct dip switch ( I have a Dallas mustang speed cal )

1996 mustang cobra... many mods...
 

98SVTContour98

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jgt58

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cbrown9064

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I have that box, been working flawlessly for years.

Retrace all wiring and make sure you have good, soldered connections. No butt connectors. Also check to make sure tranny harness did not touch EGR pipe (if you still have EGR and stock logs. If your plastic "push pins" that secure the tranny harness across the top of the bell housing are broken, things can shift around and get toasted.

If I were to bet, bad connection.

FYI, I mounted my box on the firewall and modified the tranny harness Before it plugs in to the car harness.
 

98SVTContour98

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thanks, I'll pass this info along. I wish I had enough know-how to check this out myself b/c this has been frustrating and there's not a lot of shops around here who work on these cars.

Could a dealership install this?
 

Taco_Crisma

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I have issues with my DM speedcal very similar to yours. Mine has been installed for 12+ years however. Wiring or connection is probably shoddy on mine, the Speedo will kick on and off when I hit bumps haha, and it's about 10 mph off in 4th/5th gear.

I'm in the same boat as you, it's a bit foreign to me since I didn't do the install myself.

FWIW, when your Speedo is off the car will stall out at almost every deceleration+braking. Has something to do with the car basically thinking it's idle but inertia is being placed against it. Someone here could probably explain it better.

It's also maddening, so I feel ya. Imagine it doing that on first start of the year and your battery crapping the bed on a major road in a turn lane. Yeah...
 

98SVTContour98

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ok well based on what everyone is saying, it sounds like an issue with either the wiring or the module itself....I'm gonna call around to find a shop that will take a look at it....the Ford dealership said they couldn't help me.
 

cbrown9064

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Are you at all handy with basic hand tools? If so, the directions for the Ford box are pretty thorough. You could probably handle it just fine!

If I recall correctly, you need power, ground and one wire goes to the VSS and the other goes to the car (computer/speedo). Basically you are "intercepting" the VSS signal and modifying it with the box.

Give it a look see! :)

Here is a link to the box. Only 4 wires...https://performanceparts.ford.com/part/M-4209ADPT-AC

Here are the instructions...http://www.jegs.com/InstallationInstructions/300/397/397-speed.pdf
 
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98SVTContour98

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Are you at all handy with basic hand tools? If so, the directions for the Ford box are pretty thorough. You could probably handle it just fine!

If I recall correctly, you need power, ground and one wire goes to the VSS and the other goes to the car (computer/speedo). Basically you are "intercepting" the VSS signal and modifying it with the box.

Give it a look see! :)

Here is a link to the box. Only 4 wires...https://performanceparts.ford.com/part/M-4209ADPT-AC

Here are the instructions...http://www.jegs.com/InstallationInstructions/300/397/397-speed.pdf

I'm good with tools and building stuff, but electrical ain't my thang. lol
 

Bishop03

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Good morning, I have a T56 with the same problem rather than buying another speed cal I am going to go back to stock and use my SCT tuner to correct. I would look at doing it that way.
 

IronSnake

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Good morning, I have a T56 with the same problem rather than buying another speed cal I am going to go back to stock and use my SCT tuner to correct. I would look at doing it that way.

The SCT tuner, unless you have everything 99-04 grade, will not correct the physical speedometer gauge. You will have to change the gear or use a speedo gauge to correct the display. The Tuner will only correct the algorithm within the ECU.
 

Bishop03

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Hey Ironsnake I have an SCT Tuner I called them on Monday and directly asked them if I could do this and they said yes. So just to clarify the ECU will get the proper speed but my physical speedo without a speed calibrator we continue to read the wrong speed.
 

98SVTContour98

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Can anyone help me out...I want to use an Ohmmeter to test the ground wire (per ford's request).

I've never used one before...soooo any information helps lol
 

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