Autometer Electronic Speedometer Install

[ARTTII]

I'm planning on using an Autometer electric speedometer (no cable). Can I use the OEM Vehicle Speed Sensor (VSS) on my '93 lx 5.0 with T5?

If so, should I tap into the #3 or #6 wire? I'm thinking it should be the #3 wire since it is the positive side but I'm looking for confirmation.

Thanks

 

[ARTTII]

I should have added this is the wiring diagram I was looking at to determine #3 and #6 for the VSS.

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

 

[ARTTII]

Nobody?

I will try and contact Autometer. Since they would be closed until Monday, I went ahead and tried my "best guess".

I split the #3 pin (positive ECM/VSS) wire in two. Connected the VSS side to the 'signal' terminal on the speedometer. Connected the ECM side to the 'output' terminal. I left the #6 wire untouched.

Result w/calibration: I get ballpark accurate speeds readings above 40 mph. Below 40 mph I get NO reading. The needle does have some bounce to it, like a dry cable would. I think I need to pickup a new VSS and see if that changes anything.

In the mean time if anyone has installed one of these is this the setup you did? or did I mis-wire it?

Thanks,

 

[ARTTII]

Can anybody at least verify that I should be seeing some voltage at the #3 pin during low speed (i.e., <30 mph?)


I think I might just have a bad VSS...

 

[795.0pacecar]

I wish I could help, but I had bad luck with the autometer electronic speedo and ended up frying one.

 

[ARTTII]

Thanks, and that is exactly what I'm afraid of! Frying one!

I called Autometer today and talked to a tech, here is the short of the answer (might help someone in a search later):

The signal should be wired direct to the positive (grey w/black stripe in my case) wire on the vehicle speed sender (at the transmission). The output is to be left unhooked up -->disregard the instructions.

Here is the issue I still have, I'm not generating enough "power/signal" to activate the gauge until I reach the 40mph. I figured it had to be the VSS so I went and picked up a FORD VSS at $40. Ouch. It only marginally helped. I still show no reading until I pass 30mph, then all is good.

I'm going to try two things. In this order:
1.) Put my old 2.73 gear speedo gear on there. That will get the VSS turning faster and should yeild more signal. I will see where that gets me. If not, then
2.) I will take the ECM out of the loop. Effectively running w/o a VSS input to the computer. I did a test run of this today and did not experience any ill effects, even when doing a panic stop.

I'll update this post if I get it right.

 

[795.0pacecar]

If that doesn't work, pm me and I'll give you an autometer VSS for the price of shipping.

 

[ARTTII]

I'm going to try two things. In this order:
1.) Put my old 2.73 gear speedo gear on there. That will get the VSS turning faster and should yeild more signal. I will see where that gets me. If not, then
2.) I will take the ECM out of the loop. Effectively running w/o a VSS input to the computer. I did a test run of this today and did not experience any ill effects, even when doing a panic stop.

I'll update this post if I get it right.

UPDATE:

I'm up and working! I first attempted to swap in my old speedo gear. That did have some effect, my speedometer would read at lower speed, but still not until I hit 20 mph or so.

The fix came from taking the ECM out of the loop. I chopped and capped off the #3 and #6 ECM wires. Ran the VSS exclusively with a ground and signal wire directly to the speedometer. It works flawlessly. Never seen a speedometer needle move so smoothly throughout its range!!!!!! I then recalibrated it (drive a known 2 mile loop) and all is good!

I thought I'd post this in case anyone does a search and turns this thread up in the future.

p.s. why do our cars even have the VSS? Mine didn't really have any effect on the operation of the car...

 

[jrichker]

UPDATE:

I'm up and working! I first attempted to swap in my old speedo gear. That did have some effect, my speedometer would read at lower speed, but still not until I hit 20 mph or so.

The fix came from taking the ECM out of the loop. I chopped and capped off the #3 and #6 ECM wires. Ran the VSS exclusively with a ground and signal wire directly to the speedometer. It works flawlessly. Never seen a speedometer needle move so smoothly throughout its range!!!!!! I then recalibrated it (drive a known 2 mile loop) and all is good!

I thought I'd post this in case anyone does a search and turns this thread up in the future.

p.s. why do our cars even have the VSS? Mine didn't really have any effect on the operation of the car...

The VSS speeds up the idle as you slow to a stop. This is supposed to prevent stalling as you slow down, particularly with auto trans cars and cars with A/C. Many Mustangs have had the idle settings tampered with to hide other idle problems, so a missing VSS isn't evident. It will generate a 27 or 29 code when you dump the codes.

It is possible to run an electronic speedo and use the VSS too. If you have a good electronics background or know someone who does, I will be glad to share some ideas with you.

 

[DaBoss302]

back from the DEAD............

trying to resolve this same issue. I was told by autometer to put a inline resistor 10k from radio shack ?

if the hall effect 3 wire sensor is used instead does this same as cutting out the VSS for the computer

I don;t want any ill effects if I install..........such as no cruze control or going dead because of low idle

 

[jrichker]

In order to use the cruse control and computer control of the idle , the stock VSS sensor needs to remain in place.

The added resistor may work, just be sure to solder the connections & cover them with heat shrink tubing.

 

[DaBoss302]

The use of the 10k ohm resistors did not work. I also would say this has to be a bad gauge but trying to fight the idea that that is true.

I have rerouted the wire per autometer. I have tried two diff vss sensors.
I have tried resistors. only thing next is the autometer speed sensor.

from what I have read not manypeople have to use this?