A VSS/Dakota digital question for someone smarter than me..

[suburban99]

1972 K10 LQ4 swap, TH350 NP205. Truck starts runs drives good. Had a misfire problem that was cured by adding a Dakota digital SEN-01-4160 inline on the speedo cable and a SGI-5E generator interface in the cab. When I plug my Bosch 1100 in to read live data, I have no speed. The red light on the Interface flashes when truck is moving and I do not get the misfires I was getting previously. So I assume that the ECM knows the truck is moving, just not how fast it's going or if it's under load.
I have the following wires hooked to the interface:

Power = Power when key on
Ground = Chassis ground and black wire on speedo cable pulser
Sensor round = Pin 23 red on the ECM (VSS reference low 6.0 only)
Signal in=grey wire on speedo cable pulser
Sensor PWR= no wires
Out 1= no wires
Out 2= no wires
Out 3= To ECM pin 22 red (VSS speed sensor signal)
Out 4= no wires
Out 5= no wires

Interface is programmed for L-H and 128000...

I have swapped wire on 22-23 and 23-22 but truck misfires, and no speed is shown on Bosch 1100.

I called DD today and they said only use 1 wire from the ECM (VSS speed sensor) and wire it to Out 3..then cap off the wire on pin 22...I tried it but truck misfired. Hopefully some's done the same thing and knows what I am missing. Eventually I want to get truck tuned so I will need the speed to ECM to work according to the tuner?..

[dayj1]

Originally Posted by suburban99

1972 K10 LQ4 swap, TH350 NP205. Truck starts runs drives good. Had a misfire problem that was cured by adding a Dakota digital SEN-01-4160 inline on the speedo cable and a SGI-5E generator interface in the cab. When I plug my Bosch 1100 in to read live data, I have no speed. The red light on the Interface flashes when truck is moving and I do not get the misfires I was getting previously. So I assume that the ECM knows the truck is moving, just not how fast it's going or if it's under load.
I have the following wires hooked to the interface:

Power = Power when key on
Ground = Chassis ground and black wire on speedo cable pulser
Sensor round = Pin 23 red on the ECM (VSS reference low 6.0 only)
Signal in=grey wire on speedo cable pulser
Sensor PWR= no wires
Out 1= no wires
Out 2= no wires
Out 3= To ECM pin 22 red (VSS speed sensor signal)
Out 4= no wires
Out 5= no wires

Interface is programmed for L-H and 128000...

I have swapped wire on 22-23 and 23-22 but truck misfires, and no speed is shown on Bosch 1100.

I called DD today and they said only use 1 wire from the ECM (VSS speed sensor) and wire it to Out 3..then cap off the wire on pin 22...I tried it but truck misfired. Hopefully some's done the same thing and knows what I am missing. Eventually I want to get truck tuned so I will need the speed to ECM to work according to the tuner?..

You don't need the SGI-5E at all. Take the two wires from the SEN-01-4160 and connect them to the red connector pins 20 and 21. It's an AC signal, so it doesn't matter which wire to which pin as long as its 20 and 21.

That should get you reading a speed, but it'll be really low since the original 4l60 or 4l80 speed sensor would have put out 40 pulses per driveshaft revolution and the DD one puts out 8 pulses per speedometer cable revolution. If your speedo is reading correctly (meaning that you have the correct speedo drive gears in the transmission), you will be getting 8000 pulses per mile. Your tuner can do the math with your gear ratios and tire size to adjust the pulses per mile in the tune.

[davepl]

I had to reprogram my ECM because I ordered the automatic version of the LS3 crate motor to get the rebate, then reprogrammed it to be the manual trans. Along the way I had to edit the pulse per mile on the speedo input, so just FYI that's a configurable input. So long as you know the number of pulses per mile for the speed sensor you're using, you can adjust it to match.

Side note - I see all of the Dakota Digital products use the same little "project box" with an LED display and screw terminal hookup. Anyone ever seen that as a standard project box you can buy?

[suburban99]

Originally Posted by dayj1

You don't need the SGI-5E at all. Take the two wires from the SEN-01-4160 and connect them to the red connector pins 20 and 21. It's an AC signal, so it doesn't matter which wire to which pin as long as its 20 and 21.

That should get you reading a speed, but it'll be really low since the original 4l60 or 4l80 speed sensor would have put out 40 pulses per driveshaft revolution and the DD one puts out 8 pulses per speedometer cable revolution. If your speedo is reading correctly (meaning that you have the correct speedo drive gears in the transmission), you will be getting 8000 pulses per mile. Your tuner can do the math with your gear ratios and tire size to adjust the pulses per mile in the tune.

Currently I am using pin 22 and 23 as my ECM print says to use these for a 6.0? Or am I reading it wrong? I don't have any wire on 20.

[dayj1]

Originally Posted by suburban99

Currently I am using pin 22 and 23 as my ECM print says to use these for a 6.0? Or am I reading it wrong? I don't have any wire on 20.

22 and 23 are the input speed sensor connections for a 4l80. The ISS sensor is the same part as the VSS, but, if you want to send a speed signal to your PCM, use 20 and 21.

[suburban99]

Originally Posted by dayj1

22 and 23 are the input speed sensor connections for a 4l80. The ISS sensor is the same part as the VSS, but, if you want to send a speed signal to your PCM, use 20 and 21.

Ok I will try this, but what's the ISS sensor...I am unfamiliar with that term...

[Wildkarde]

ISS is Input Speed Sensor, used on 4l80e transmissions, 20 and 21 and the wires for a the Vehicle Speed Sensor, 22-23 say for 6.0 because they are the engines that came with the 4l80e.

Your tuner should be able to set both the pulses per revolution and the pulses per mile in the tune if you know which speedo gears are in the transmission.

[suburban99]

Thanks for the replies. As suggested I used ECM pin 20 red connector to the Dakota digital SEN-01-4160 (black wire speedo cable pass thru pulser). Then I connected the grey wire from the Dakota digital SEN-01-4160 to the signal in pin on the DD SGI-5E. Then connected OUT-3 from the DD SGI-5E to ECM pin 21 Red connector.
Bosch 1100 now shows a speed and it's close enough to actual! ECM is still set for 128000 pulses and the DD SGI-5E makes it really close.

Right away I noticed when I came to stop sign the engine idled down to about 8-900, then when stopped it went to 560RPM...previously the RPM would drop right off when coming to a stop, or slowing down..thanks guys!