No Cummunication while engine is running

FastWillz · New Member Joined: Nov 18, 2004 Posts: 11

Hello

I have a 4L60E Transmission, I am able to upload and download while the engine is not running. As soon as I start the engine, I can no longer find the TCU.

I am able to check most of the sensors with out the engine running, well, at least I can see the Analog inputs changinging, and have tested the break input. What I am not able to check are the speed sensors, and the range switches, nor can I check the outpust. However after a test drive it does change though all the gears, so I can only guess that all the outputs are working fine.

I the issuse I do have is, there is no Speed indicatior.

Is there a way I can lower the comm port speed? to help reduce any interfearance? I have been able to select the port though the control panel and reduce it that way, all the way down to 75bps, but didn't appear to affect anything. I am using a USB connector that i got from you guys.

I am not quite ready to rip apart the connector, but if it comes down to that to maybe re-route the cable, how hard is it to get a new cable with the pin connecters, or even the inserts the selfs incase of breakage?

Russ · PCS Employee Joined: May 12, 2004 Posts: 286

On some GM applications we have had issues driving the stock speedometer directly with our standard speed output. If you are using the speed output on our unit, try disconnecting it then check the communications. This could be a problem on some aftermarket speedometers but it hasn't been reported.

If this turns out to be the problem we have a simple fix that requires rewiring the speedometer to one of the driver outputs.

FastWillz · New Member Joined: Nov 18, 2004 Posts: 11

Cutting that one wire, has enabled me to use the TCU while online. Hurray!

Ok, now how do I fix the speedo?

I want to use the TCU speed output.

Before upgrading to your unit, I was using a DRAC, and a controller for the GearVendor overdrive unit. My end goal, is to replace the entire controller, and use your unit to not only control the transmission but also the overdrive unit. It has been recommend that I use your controller in a 6 speed mode, and that is where I want to start, before getting more adventures and going to an all out 8 speed, some how but that is down the road.

I am using the stock Speedo that came in the 1997 Trans AM, its a 155MPH speedo, also the Body computer taps off of this for the cruise control. I like the Cluster in the Trans Am for me it has a nice look and would like to keep it.

Russ · PCS Employee Joined: May 12, 2004 Posts: 286

We have a special firmware version that will allow you to drive the speedometer off of digital output 6.

www.powertraincontrolsolutions.com/download/tcu/firmware/1.1.5c.rom

Login: beta
Password: unet

Just rewire the speedometer to digital output 6. In the calibration for digital output 6 set the function to disabled and the drive type to +12v.

FastWillz · New Member Joined: Nov 18, 2004 Posts: 11

Ok, got it wired up. and re-programmed

Didn't do anything however. for the Speedo Sad

I can still talk with the TCU

FastWillz · New Member Joined: Nov 18, 2004 Posts: 11

Any thoughts here guys?

I still can't use my speedometer

But it does display a speed on the laptop while driving. Not the best solution for driving to keep looking over at a laptop?

Also i have been only using 4 speeds. When i try to program a 5 gear for the GearVendor, it does a doubel shift on an up shift and a doubel shift on a down shift. Which is what I wanted to avoid.

I'll be in 4th O/D for the 4L60E, and when the speed it met, to up-shift to 4th and GearVendor engraged. I down shifts to 3rd, then and then up-shifts to 4th with the GearVendor O/D unit.

Also same thing when down shifting out of 5th (4th + GV) it will shift to 3rd then Up-shift to 4th.

What the heck. No Speedo, which is one of the things I wanted to fixe by removing the Drac, I could never get it calabrated close enough. So did I waist my money? Should I send the unit back? I wasn't going to bring the shift problem up until i got the speed fixed, but lack of reponces leaves me wondering?

Russ · PCS Employee Joined: May 12, 2004 Posts: 286

Fastwillz,
I appologize for the delayed response. Everyone in the office just got back from the SEMA show in Las Vegas.
To get started, upload your calibration from the unit and email it to support@ptcs.us . The double shift problem is most likely just a calibration error.
As for the Speedometer, first go to digital output 6 and set the drive type to Ground and see if it works. If not, disconnect the speedo from the output and connect a multimeter to it. When you are sitting still the voltage should be around 1/2 battery voltage ~7 volts. At about 30-40mph the voltage should be 3-4 volts.