67LS3

I went on the shakedown ride on my 67 camaro with gmpp LS3 and gmpp 4l60e with the gmpp trans controller. The autometer electronic speedo steals the vss signal from the trans controller. That makes the trans not shift... Unplug the signal to the speedo and car works great. Autometer says to add a resistor on the signal wire to their speedo. Doesnt work. I have worked with autometer and they dont have an answer now other than to add a dakota digital box??? Anybody else have this issue? I need this fixed asap for Power Tour.

John McGraw

Does your ECM not have a Speedometer output? I have never tied into the VSS, but directly to the ECM speedometer output. I know the Carb guys use the VSS, but I think most of the EFI guys use the ECM output.



Regards, John McGraw

67LS3

the ecm and tcm are basically stand alone and only share a couple of sensors.

BanditDave

iTrader: (11)

There should be a speedo output from your ECM...but that is speaking strictly as something you take from a donor car. I am not very familiar with the GMPP set-up but my guess is that it is something in the way you wired it.

Can you describe how the wires are spliced in?

Thanks,
Dave

poorhousenext

If worst comes to worst, you might want to look into this little item from Classic Instrutments.

Sky Drive GPS Presented by Classic Instruments

With the push of a button, you can program your vehicle's speedometer from
the convenience of your garage to read in miles per hour, kilometers per hour or knots. The omnidirectional antenna gives you added mounting choices. This new innovative product works with any Classic Instruments or other manufacturer's speedometer. Two additional wires give you added features and benefits. The first gives you an extra speed signal for cruise control. The second wire can activate a relay or light which does a variety of things such as locking your doors or turn on a speed warning light at a predetermined speed.

http://www.classicinstruments.com/

67LS3

I have wired it the way autometer has suggested directly from one side of the vss to the trans controller signal in and using the same wire to feed the speedo. No speedo output from the ecm with the gmpp.

deuce4935

iTrader: (2)

Are you sure you arent misidentifying the vss input and output connectors, they look exactly alike. The 4l60e's dont use the vss input connector but the 80e's do.

67LS3

i was looking at this old thread. autometer has a problem with their speedo taking the signal from the tcm and ecm. they will tell you to try a resistor,etc. it wont work. get the dakota digital box and it is done.

hookemdevils22

iTrader: (12)

get a speedhut gps speedo and you don't have to worry aboot wiring.

poorhousenext

Probably be hard to check with transmission installed, but your problem may be the lack of 4L60/65E upgrade needed to provide VSS signal that is found on all 4L70E transmission, used with LS3.

Back in 2008 when I started LS3 with 4L65E, I found that out the hard way. Might want to check with RPM transmissions as I've heard they are one of the cheapest places to get a 4L60/65 modified with sensor. This may mean your TCM and/or harness could also be a problem if it's not compatible with 4L70E as well as 4L60E

You might want to disconnect the main harness connector to transmission and see f you can count the number of pins in connector and then maybe by using inspection mirror, count the number in connector in trans. What you are looking for is in below picture. The two extra pins provide VSS information to ECM.



You might want to check with any of the Companies that make wire harnesses for LS engines swaps and see if what I'm telling you is correct when doing LS3 swap with 4L60/65E.

S10xGN

iTrader: (11)

We just finished a '68 Camaro LS3 with a TCI controlled 4L80. The owner tried getting a signal from the TCI box output to run his Autometer speedo. Trouble is, the speedo is looking for a 5v square-wave and the TCI box only outputs a 12v square-wave. We ended up teeing the signal wire into the TOSS sensor signal (5v sq) that goes to the TCI box...