Another VDO GNX Style Dash w Electric speedo issue

[greeneyegi]

I have the whole dash working except the mph @ the scanmaster .
The Speedo works on the gauge. I can get the scanmaster to read MPH but wrong speed.
If I wire it up with the schematic i have the tach stops working.
I need the wiring schematic for the tac and speedo gauge.
This is older VDO.

 

[1KWIKSIX]

Dunno if these instructions help? They're from my AVC (GNX Style Dash) with VDO gauges.

 

[greeneyegi]

It says use the green and black wires that go to the green box im assuming. What do those two wires wire up too?

 

[1KWIKSIX]

the only green box I know of is the factory VSS sending unit

 

[greeneyegi]

the only green box I know of is the factory VSS sending unit

Does the factory vss buffer (green Box) stay after the installation?
Or is it removed and we wire directly to brown (to ecm) and red(cruise), removing the green box (buffer)?

 

[1KWIKSIX]

These directions are for a Mechanical VDO Speedometer. See points 20, 21, 22 in the directions which states to remove the factory's green VSS box and install the supplied bosch VSS which is driven by the speedo cable and would be installed in the engine compartment directly where the 2 piece speedo cable is joined and is placed under the brake booster. The green & black wires get connected to the new VSS via crimp connectors , whereas the red is not used and is taped. Think you may need a different VSS for your VDO Electric Speedometer.

 

[1KWIKSIX]

Perhaps these directions with pictures will help?

 

[GNRick]

I have the old style cable driven vdo speedometer and the green buffer box. The old style vss goes between the speedometer cables and has two wires that go thru the firewall and connects to the green buffer. Been awhile since I've looked at it but I assume the red wire on my buffer is not used. My issue is the cruise control only works intermittently.

 

[1952ray]

Does the factory vss buffer (green Box) stay after the installation?
Or is it removed and we wire directly to brown (to ecm) and red(cruise), removing the green box (buffer)?

I took mine out ( green box ) there’s enough shit under the dash as it is. Yes brown to the ECM red to cruise. I have a electric speedo, however I have a 2 wire speed sensor that’s screwed into the trans, two wires that come out the sensor, one to ground the other wire, made three wires out of that one. One to brown (ecm) one to red ( cruise) and last one to the speed O. No cable, took the green box out.However I do not have the VDO. Mine is the NVU gauge. I am not aware of any speed O meter that’s electric that uses a cable. But you do have to have a signal from the trans. Hope I haven’t really screw your head up with this.

 

[1952ray]

I have the old style cable driven vdo speedometer and the green buffer box. The old style vss goes between the speedometer cables and has two wires that go thru the firewall and connects to the green buffer. Been awhile since I've looked at it but I assume the red wire on my buffer is not used. My issue is the cruise control only works intermittently.

The red wire on the VSS box is the cruise wire. If it only works once in a while something is wrong down at the brake pedal .

 

[greeneyegi]

I took mine out ( green box ) there’s enough shit under the dash as it is. Yes brown to the ECM red to cruise. I have a electric speedo, however I have a 2 wire speed sensor that’s screwed into the trans, two wires that come out the sensor, one to ground the other wire, made three wires out of that one. One to brown (ecm) one to red ( cruise) and last one to the speed O. No cable, took the green box out.However I do not have the VDO. Mine is the NVU gauge. I am not aware of any speed O meter that’s electric that uses a cable. But you do have to have a signal from the trans. Hope I haven’t really screw your head up with this.

Cant screw up my head, That was done yrs ago.
But i do have the speed cable from the trans to a VSS with 3 wires. Rd-blk-wht.
They attach to the speedo. I have 2 different casper type boxes. One sqaure the speed and one for the tach its rectangle .
The electric speedo is right on. So i know the vss is good.Its the ecu i cant get to work but it goes straight to 55mph and higher wired one way.
There is something weird about the yellow wire out of converter box, If i unplug it from tach ,tach stops working if its plugged into tach tach works. Yellow wire is supposed to be to cruise.

 

[1952ray]

Cant screw up my head, That was done yrs ago.
But i do have the speed cable from the trans to a VSS with 3 wires. Rd-blk-wht.
They attach to the speedo. I have 2 different casper type boxes. One sqaure the speed and one for the tach its rectangle .
The electric speedo is right on. So i know the vss is good.Its the ecu i cant get to work but it goes straight to 55mph and higher wired one way.
There is something weird about the yellow wire out of converter box, If i unplug it from tach ,tach stops working if its plugged into tach tach works. Yellow wire is supposed to be to cruise.

Damn don’t know what to say about that !!

 

[captndave737]

I took mine out ( green box ) there’s enough shit under the dash as it is. Yes brown to the ECM red to cruise. I have a electric speedo, however I have a 2 wire speed sensor that’s screwed into the trans, two wires that come out the sensor, one to ground the other wire, made three wires out of that one. One to brown (ecm) one to red ( cruise) and last one to the speed O. No cable, took the green box out.However I do not have the VDO. Mine is the NVU gauge. I am not aware of any speed O meter that’s electric that uses a cable. But you do have to have a signal from the trans. Hope I haven’t really screw your head up with this.

1952 Ray,

Do you have a 2 pulse going to everything? I thought the Electric speedo needed at least an 8 pulse and the cruise and eco needed a 2 pulse.

I remember when we first put in the NVU gauges most of us used 2 separate VSS's piggy backed at the tranny. One for the speedo and one for the cruise and ECM. As far as I can tell the only thing the ECM does is apply the TCC. My speedo was always jumpy with that set up.

I recently went to a GPS sensor for the speedo and its smooth as silk and dead nuts on. I have a 2 pulse VSS going to the Cruise and the ECM. I still have the Buffer but if it can be removed I'll do that to get rid of one more thing.

 

[1952ray]

1952 Ray,

Do you have a 2 pulse going to everything? I thought the Electric speedo needed at least an 8 pulse and the cruise and eco needed a 2 pulse.

I remember when we first put in the NVU gauges most of us used 2 separate VSS's piggy backed at the tranny. One for the speedo and one for the cruise and ECM. As far as I can tell the only thing the ECM does is apply the TCC. My speedo was always jumpy with that set up.

I recently went to a GPS sensor for the speedo and its smooth as silk and dead nuts on. I have a 2 pulse VSS going to the Cruise and the ECM. I still have the Buffer but if it can be removed I'll do that to get rid of one more thing.

Yes I have the 2 pulse going to everything and it works fine, however I’m the only one who got the short sweep dash which only had to have a 2 wire 2000 pulse sensor

 

[captndave737]

That explains it.

 

[1952ray]

That explains it.

What kind of GPS speedometer did you get ? Do you have the GPS sensor and the 2 pulse piggy back on the trans?

 

[captndave737]

I just got a sender for my NVU speedo. I have the performance 2 gauges. The GPS sender is Autometer. The antenna is about 1 square inch and I have it in the corner next to the front speakers so it's barely visible.

 

[1952ray]

I just got a sender for my NVU speedo. I have the performance 2 gauges. The GPS sender is Autometer. The antenna is about 1 square inch and I have it in the corner next to the front speakers so it's barely visible.

Thank you Dave

 

[greeneyegi]

Im going to open the dash on my car(exact same) and see what the hell is going on. I will report back soon.Thanks for the ideas though.

 

[greeneyegi]

I checked the vdo setup in my car and the difference is the vss sender is 2 wires and 3 wires.
I have the red vss wire butted to the green and red wire on my buffer.
The new dash is 3 wire sender.