67-72 Electric speedo

[jjzepplin]

I want one too!

[ls1nova71]

Originally Posted by jjzepplin

I want one too!

PM sent

[jjzepplin]

So my donor car 99 Trans Am has a round pattern needle driven speedo but has a tach. Would this one work?

[Aross72]

67c10rusrbuket, can I get the bracket and cover? How much and how do I get the items?

[Curtb1971]

Alright, finally have an update on mine. I changed some things around. Instead of running a separate light for the check eninge light I used the temp light location in the gas gage by cutting out the filter of the s10. Also swap the brake warning filter. After the initial start the 60lbs oil gauge was pegging so swapped a 80lbs gauge in.
Here is the big kicker. I'm not sure I'll be able to run this set up in my truck because the speedo reads 10x of what it should. I'm running a 2008 genIV ecm and tcm with a 4l60e. Does anyone know if the speedo pulse output can be changed in a tune?

[jjzepplin]

10x or 10mph?

[Curtb1971]

Originally Posted by jjzepplin

10x or 10mph?

It's wierd because of the rate that it climbs but it is around 10 times what it should be. 0 to 100 in a second

[ls1nova71]

Originally Posted by Curtb1971

It's wierd because of the rate that it climbs but it is around 10 times what it should be. 0 to 100 in a second

I haven't messed with GenIV stuff much, but if I remember correctly, they don't have a dedicated speedo output from the ECM, it was a CAN BUS signal to the instrument cluster. They do however have an 128k ABS output that I was thinking could be programmed to work with a speedometer. I am assuming this is what you have it hooked to? Do you have a local tuner that can look at it for you? It turned out nice, would be a shame not to be able to use it.

[Curtb1971]

Originally Posted by ls1nova71

I haven't messed with GenIV stuff much, but if I remember correctly, they don't have a dedicated speedo output from the ECM, it was a CAN BUS signal to the instrument cluster. They do however have an 128k ABS output that I was thinking could be programmed to work with a speedometer. I am assuming this is what you have it hooked to? Do you have a local tuner that can look at it for you? It turned out nice, would be a shame not to be able to use it.

Hey Eric, I think the CAN BUS is what I have it hooked up to now, but I am working with a local tuner on the solution. I also tried tapping into the hi ref side of the vss with no luck. We will look into the abs output in hp tuners if it can be dialed down to the 4000ppm for the s-10 speedo. Fingers crossed on this one. Thanks for the reply

[cebra]

I am having a similar issue, I have 00' 4.8L with 20" wheels/50 tires, 3.08 gears, and NV3500 manual trans. My speedo is about 2x what it should be (reads 90 at 45). Does this need to be adjusted with a tune due to the tall trans/gear/wheel size?

[ls1nova71]

Originally Posted by cebra

I am having a similar issue, I have 00' 4.8L with 20" wheels/50 tires, 3.08 gears, and NV3500 manual trans. My speedo is about 2x what it should be (reads 90 at 45). Does this need to be adjusted with a tune due to the tall trans/gear/wheel size?

I'm thinking its due to a difference in speed sensors. It should be fixable in the tune though, you would have to talk to your tuner to be sure.

[cebra]

I am having it tuned Thursday so hopefully that resolves the issue. If I have the wires on the VSS backward (the pigtail I bought just had 2 black wires), would this cause the speedo to read high or would it not read at all? The pigtail on the original harness had the purple vss wire on the right so I put the right black wire to the VSS lead to my speedo so I assume it is correct but thought I would ask, thanks.

[ls1nova71]

If those two wires are switched it wont make any difference.

[jjzepplin]

Any updates for this?

[ewoody625]

It's been quite some time since I've posted on this page, but I've still found a lot of useful info including the write up on this Speedo conversion, so thanks for that. I'm hoping I can get some help wiring this thing. I've tried to follow the picture but it's a bit difficult with all the wires bundled together. Thanks again for the write up and any help is much appreciated. The bottom picture is what I have so far.

[ls1nova71]

It looks as though you have most of it figured out. You just need to tie the dash lights together and add ignition power, ground and a signal wire for the gas gauge. Is there something specifically you need to know?

[ewoody625]

Originally Posted by ls1nova71

It looks as though you have most of it figured out. You just need to tie the dash lights together and add ignition power, ground and a signal wire for the gas gauge. Is there something specifically you need to know?

Do I tie in the turn signal lights with the rest of the dash lights? It looks like you grounded something above the fuel gauge? I was thinking it might be easier if I wire my plug into the truck harness first and then follow it over the the gauges? The ignition power needs to run to each gauge?

[ls1nova71]

Originally Posted by ewoody625

Do I tie in the turn signal lights with the rest of the dash lights? It looks like you grounded something above the fuel gauge? I was thinking it might be easier if I wire my plug into the truck harness first and then follow it over the the gauges? The ignition power needs to run to each gauge?

You don't tie the turn signals with the dash lights because if you did, they would light up whenever the dash lights are on. They need to be hooked up to the wires that power the turn signals, they are dark and light blue. The ground above the gas gauge is just where I decided to ground the whole cluster, you need to be sure it has a good ground.

You can wire the truck side first if that makes it easier for you, it doesn't matter which you do first.

Yes, all the gauges that are electric will need their own ignition power.

[ewoody625]

Originally Posted by ls1nova71

You don't tie the turn signals with the dash lights because if you did, they would light up whenever the dash lights are on. They need to be hooked up to the wires that power the turn signals, they are dark and light blue. The ground above the gas gauge is just where I decided to ground the whole cluster, you need to be sure it has a good ground.

You can wire the truck side first if that makes it easier for you, it doesn't matter which you do first.

Yes, all the gauges that are electric will need their own ignition power.

Duh... that makes sense. Thanks for the help

[ewoody625]

So I think I have this figured out, but I'm unsure of where the red and green wire go?

[jjzepplin]

Originally Posted by ls1nova71

No, that's not it. It goes more like.....It's Tricky to rock a rhyme, to rock a rhyme that's right on time
It's Tricky, it's Tricky (Tricky) Tricky (Tricky)
It's Tricky to rock a rhyme, to rock a rhyme that's right on time
It's tricky, tricky (Tricky) tricky

But seriously, what is your issue?

I missed this one! AAAAhahahahahahaha!
On a more serious note... I have not done my swap yet and am out a few months due to moving etc. I am very thankful you fellas are figuring this out though. I may have missed it in here but when this is done and working right - I can still have my stock tach as well?
Oh and you are very right! It's tricky! So you are right on time...

[ls1nova71]

Yes, you can still have the factory tach, you just have to trim one side of the face of it slightly to clear the speedo. It doesn't show when installed so you will never notice it. I will look and see if I can find a pic.

[ls1nova71]

Originally Posted by ewoody625

So I think I have this figured out, but I'm unsure of where the red and green wire go?

You mean pink and green? There are pins that stick up on the back of the circuit board, and by them they are labeled what they go to. The pink goes to Ignition power and the green goes to Speedometer out put. If I remember correctly they are labeled IGN and SPD.

[ewoody625]

Originally Posted by ls1nova71

You mean pink and green? There are pins that stick up on the back of the circuit board, and by them they are labeled what they go to. The pink goes to Ignition power and the green goes to Speedometer out put. If I remember correctly they are labeled IGN and SPD.

Yes pink and green. I have them on the circuit board but I don't know what to hook them up to in the truck. I did want to ask, there was a wire labeled ammeter to ignition. Can I use that as my ignition power? Would i get speedometer output from the ecm? Or is that what vss is? Sorry for all the questions but i think i got in over my head on this one.

[ls1nova71]

I'm not sure what that wire labeled ammeter is, but I probably wouldn't use that for ignition power. The gauges will have power already going to them, so you would just need to use that wire. The speedometer wire would come from the PCM.