Sorry if there is already a thread for this, but I didn't find one.

I want to put a 140MPH cluster in my 85. Problem is 86+ have an electric speedometer and my 85 has a mechanical. Not a big deal to change over, but I thought that I would add that in.
I have also heard that you need to re-pin the dash to get the gauges to work properly. Is there any easy way of going about this swap?

 

I've done it and have some hand written papers on it that I could possibly scan or type up. And yes you need to repin the dash but it is not very hard. Just take your time and pay attention to what you are doing and you should be fine. I've been meaning to did them up for another thread. If I have time tomorrow I will dig them out.

And just a note the swap is totally worth it as IMO the 86+ gauges look so much nicer than the 85 style.

 

Thanks for responding! I'm with you 100% on the look of the 86+ gauges.

How long did it take you to repin the dash? It seems like I'm always looking for time to work on my car, so I don't want to have it toar apart over 3 days and end up forgetting things.

 

I did it in one night. It took longer to figure out my game plan than actually repining.

 

Here is some stuff which should help. I can't claim ownership of the two cluster diagrams as I found them on this forum but cannot find where it was exactly. The other two are my scribble I used to plan my attack.

This is the 85 cluster


This is the 87+. Not sure if 86 is the same. I used a 89 cluster


Pretty self explanatory. One thing to notice is the 89 gauges uses two illumination wires but the 85 harness only has one. So you have to split the single wire into two and on each connector it goes to pin 3.


This is what I used as a check list and also labeled some of the wire colors. The "B" found after some of the numbers stands for bottom connector.


Now keep in mind I do NOT have a factory computer so I did not bother with any of the VSS wires other than one to run to my dakota digital box. If you are using a factory setup I believe you would need a factory speedo buffer box to wire to go between the VSS, speedo, and computer. I also did not bother with the SES light

This is a diagram of the factory buffer box



For those who don't know this is the difference between 85 and later gauges. Notice the oil pressure and fuel gauge swap. Plus the fuel gauge is buffered so it doesn't go to E on a turn.


The connectors after pin change


The main reason these are so much better.

 

I know it's a little off topic but how do you plan to swap out mechanical speedo with electric? I've been trying to figure it out for a couple of day now

 

Not sure what you mean but you simply swap out the cluster and then get a VSS that goes into the trans and wire it to the cluster. The cluster swap is the hardest part the rest is easy.

In my case I went to a T56 so I more ot less needed to do the swap as the T56 has no provision for a cable.

 

I just did this yesterday, I didn't need a buffer box, just put the 2000ppm output to the brown wires and the 4000ppm output to the gauge from the SGI box
AND I didn't need to split the illumination wire, I have an 87 140 mph cluster, I actually used the other diagram that is 5? pages after the one you posted a picture of...
ALSO if you noticed, the wire colors on the 85 are the same for everything as the later ones (from what i noticed in the tech article about a firebird electric speedo swap)
I wish i could have kept the 85 cluster, it looks better to me and had Kpa for oil and C for temp

 

I have one question I have an 84 Firebird (from what I understand first year for the OBD I computer) I'm also doing the 86-90 electric speedometer swap what wire do you have to hook up to the computer to keep the check engine light from coming on or is it something I don't have to worry about? I don't have factory cruise control its an aftermarket unit (car didn't come from the factory with cruise) and it has an T-5 Manual Transmission.
Any information will be helpful.
Thanks.

 

This is what you will need to convert from cable to electric speedometer.


[Classic Instruments 16-Pulse Generator Speed Sensor GM TH350/TH400/700R4, 2004R, Powerglide, Richmond, Chrysler 727/904 Transmissions.
It will also work on the GM 5 speed and I think it will work on the 3 & 4 speed manual transmissions.

Found on Jegs under VSS generator.


QUOTE=Dabesiv;5522170]I know it's a little off topic but how do you plan to swap out mechanical speedo with electric? I've been trying to figure it out for a couple of day now[/QUOTE]

 

There is a 140 mph mechanical speedo made.
I found mine on ebay. NIB for export cars.

 

hello
does this procedure also applies to 84 models?
i'm planning on changing the cluster sin ce it has died on me, i can easily get 86-90 years clusters easily, but i can't seem to fin an 84 cluster for direct replacement.
Any help will be much appreciated.
Thanx