I have a 84 Camaro with 95 LT1/T56 95 Camaro ECM. I swapped the instrument panel out for a Covan’s Classic set, and opted for the carbon fiber gauges. Because of the engine/tranny swap I am using the electrical speedo. I have the vss signal coming from the transmission into the ecm and out on the green signal wire into the gauge. Anyone who has seen one of these electrical speedo’s will know they go through a “boot up” process when power is applied. The needle will go to 80mph pause, display what I assume to be the calibration factor ,and then drop to zero and display mileage. The problem I am having is the speedo will hang at ½ needle or drop to zero and not read if I don’t have the motor started before the “boot up” process begins. I called Autometer about this problem they informed me to install a Bosch #30 relay between key on power, power to the gauge, and the starter solenoid wire. This just feels like a work around not a real solution is anyone else experiencing this problem? Also in the cold mornings the speed stops working, I have to get half way to work then magically it starts working. Any thoughts on this, the only difference I can think of is temp, could the stock vss sender be going bad? Thanks

Anybody? Nobody opted for an electric speedo in the covans kit?

Anyone running an electric autometer speedo period?

How many grounds did you hook to the speedo? Mine had to be grounded for the light, the electronics, and the VSS. I didn't realize I needed a third ground for the VSS, so mine would always act wierd, lose memory, stop working intermitantly, ect.

I didn't count the grounds when wiring it up, but I will look into it.
I do remember grounding one end of the twisted pair (vss signal wires). Maybe I picked a bad spot for that ground, I'll check it out.

Does yours hang up when starting the car?

I have an electric autometer speedo. Not sure I can help though. I too am running a T-56. I took one wire from the tranny and grounded it to the Tranny x-member I think. Then I ran that 1 wire to the speedo. Other grounds I ran to interior locations that were convenient. Mine works great.

I feel like maybe your problem is coming from a bad ground. When the car heats up, maybe the metal is expanding and making a slightly better contact or something. Def a strange problem you have.

Def check ground on the VSS fist, then report back.

I'll have to check mine. I'm running a Dakota Digital box for my older ECM, but I still have raw signal going to the speedo. I'll have to check the wiring, cause I forget how I routed it.

Autometer suggest wiring the guage straight to the Tranny and using the buffered signal leaving the speedo as input to the ecm.
http://www.autometer.com/productPDF/1140.pdf
I was told about tech support when I called about the speedo hanging up when I started the car that people were having problems when they connected the signal wire from the ecm.

Being lazy/half smart, I figured if I hooked the ecm output to the speedo when I get around to changing the final drive all I will have to do is flash the ecm and not have to recalibrate the speedo.

I left the vss wires twisted together and passed them though the dash from the driver side to passenger side, behind the radio. I have the LT1 ecu mounted under the dash (stock ecu position). I connected the signal wire there and grounded the other wire to the metal bar under the dash.

Okay, dug up the diagram I made when I hooked this up. A little different because of my buffer for the old ECM.

I took a shortcut and just split the VSS signal. It works as long as the VSS out on the back of the speedo is grounded, otherwise it wont hold calibration.

For yours I would try grounding that output, and if that doesn't work, just run it like they suggest from VSS to speedo, and from speedo to ECM.

hey, im looking to do the same swap. i have 2 question. with the autometer gauges can i remove the yellow buffer on the back of the gauges cluster?? does the buffer just cut the signal in half and send it to the ecm????

Sorry it has taken me so long to look in to this.

As Aaron_SK suggested about the grounds I only have one ground terminal leaving the speedo. This is a shared ground for the speedo electronics and the light. (The connector has two wires leaving it one going to the speedo light and the other going to ground)

Here may be the problem when I removed the instrument cluster I remembered what I did for the VSS ground. Basically I have the vss signal and ground leaving the transmission and going into the ecu. I ran a twisted pair of wires connecting one to the buffered signal wire from the ecu and grounded the other. This twisted pair leaves the ecu the signal is connected to the speedo and the ground connects to the light ground of the alternator guage. That clear as mud?

I have attached a picture of my wiring.
http://i228.photobucket.com/albums/e...VSSdiagram.jpg

I am thinking the problem is with the signal connection leaving the ecu.

Cold non working issue on speedometer fixed.

I spliced the signal wire coming from the transmission and wired one end to the ecu and the other to the autometer speedometer. It has been working fine now on the cold mornings. Amazing how things work if you actually wire them according to manufactures instructions.



Does anyone perform exorcisms on automobiles? I'm getting tired of chasing all the gremlins.