question on speedometers

[mike87gt]

ok as far as i know you can only use a 89 140 mph speedo in an 87-88. And a 90-93 140 speedo will not work in them correctly.

why is this exactly since there cable driven?


im asking this becuase im putting dash wiring from a 90 into my 87 since it had nothing when i got it. And the thought crossed my mind if im still going to be able to use my 89 140 speedo or am i going to have to get a 90-93 140 speedo.

i thought i tried a 90-93 sooedo in an 89 once and it was way off, but i cant remeber its been so long ago.


any help would be apreciated. thanks in advance.

Mike

 

[89CopCoupe]

I've never heard of this, but if it's true, my guess would be that the speedo drive gear that the cable driven gear rides off of changed ratio slightly in 90 ... 83-89 was a 7 tooth and 90 was an 8 tooth

 

[mike87gt]

hmmmmm, ive heard it and read it that i know for sure.

guess all i can do is try it out.

 

[trbkrb]

You can not just swap the complete cluster from a 90-93 car into a 87-89 car since all the gauges are wired differently. Same thing goes for using a 90-93 wiring harness with a 87-89 cluster. You can rewire the harness to work using this comparative wiring diagram: http://statefilingsoftware.com/pictures/cluster87-93.pdf

Now, the speedometers themselves both work the same with the cable drive, so you can swap the speedo mechanism between years and it will read correctly if the tranny drive and driven gears are correct for the rear end gear. Speedo year does not matter when talking about gears. The other problem is that Ford also redesigned the shape of the cluster and all the components in 90, so you can not just drop in a 90-93 speedo into a 87-89 cluster. You have to either swap the mechanisms and reuse the older model face plastic, with a new 140 gauge face, or cut and file and drill new mounting hols in the 90-93 speedo plastic face to make it fit in the 87-89 cluster. I did that and it works, but the turn signal arrows are different and the color is a bit different.

Good luck with it!

 

[super302]

 

[mike87gt]

ok well ill rewire it so i can use the 87-89 cluster with the 90-93 wiring, but i dont see where it shows what to rewire to where? or do i take the plugs of an 87-89 and rewire them to the 90-93 harness using what they have shown?

then again it prolly be easyer and less time consuming to jsut put a cluster from a 90-93 in it.

 

[trbkrb]

Yes, the easiest way is to put in a 90-93 cluster, but the 87 will work.

You just have to figure out what wires to hook up to which pin of the connector. For instance, pin 1 on both is the left turn indicator, so that one is the same. Pin 2 on the 90 harness is the high beam indicator, that is pin 14 on the 87-89 cluster. Pins 3 and 4 look to be the same, but pin 5 on the 90 is pin 7 on the 87-89. If you have the 87 harness plugs, it would be easy to wire it up to the 90 harness that way.

 

[mike87gt]

im having a lil trouble with this, after getting into it i notice obviously the 90-93 has alot of things the 87-89 dont.

and some of the things are named differently so i dont know if there the same or not.

help on this would be greatly apriceated.

if noting ill just keep going over it till i get it figured out.

thanks mike

 

[wildstang87]

or you could sell me the 87-89 cluster and buy a 90-93. how much you willing to sell it for???

 

[mike87gt]

pm sent

 

[tjm73]

When the airbag was added to the cars, the dash changed.

It'd be easier to buy a recalibrated unit for your car from like BBK it seems. That be a lot easier than rewiring it seems.

BBK will recalibrate and reface the guage (180 mph) for $69.95.

http://www.brothersperformance.com/shop/mustang/bbk2602.html

 

[bcd]

ok as far as i know you can only use a 89 140 mph speedo in an 87-88. And a 90-93 140 speedo will not work in them correctly.

why is this exactly since there cable driven?


im asking this becuase im putting dash wiring from a 90 into my 87 since it had nothing when i got it. And the thought crossed my mind if im still going to be able to use my 89 140 speedo or am i going to have to get a 90-93 140 speedo.

i thought i tried a 90-93 sooedo in an 89 once and it was way off, but i cant remeber its been so long ago.


any help would be apreciated. thanks in advance.

Mike

Its the shape man. In 87-89 the bottom was flat and 90-93 there was a cutout for the column

 

[tjm73]

Its the shape man. In 87-89 the bottom was flat and 90-93 there was a cutout for the column

That's because of the airbag.