Comm Error

[81 TransAm]

Working on another buddies car. It's a 350 SBC. He has an Avenger ECU. He converted to MPFI. We connected with the laptop and flashed the ECU to V4. Then change all our settings, did a TPS Autoset and set the timing. So far everything was good. Started the car, got the idle speed set. Then with the engine running and the laptop Online, the live data started to freeze, then it lost connection. We turned the car off, unplugged the USB and plugged it back in. Turned the key on and reconnected. It stayed connected until we started the engine, and then it started to freeze and lost connection. After doing this a few times it now does not connect at all. As soon as you plug the USB into the laptop the laptop gives an error. Something like Windows does not recognize USB device. We plugged the laptop into another ECU, and it reads it fine. We changed the USB cable to a known good one, and it still did not connect. Which leads me to think it is a fault of the ECU. We had the laptop connected to the ECU for a good couple hours, while we changed the settings. The issue only started when the engine was started.

We connect the small basic controller and we could see the real time data. We couldn't save a Global File. I'm guessing because the firmware in it is not compatible with V4, and can't be updated. Is this correct? We also unplugged the power on the ECU for 20 minutes and it didn't help. I have a 3.5" touchscreen in my car that I could use to reflash the ECU firmware. Are there any other things I should be looking at?

[Danny Cabral]

After doing this a few times it now does not connect at all. As soon as you plug the USB into the laptop the laptop gives an error. Something like Windows does not recognize USB device. We plugged the laptop into another ECU, and it reads it fine. We changed the USB cable to a known good one, and it still did not connect. Which leads me to think it is a fault of the ECU. We had the laptop connected to the ECU for a good couple hours, while we changed the settings. The issue only started when the engine was started.

I have no idea what's wrong, unless the internal USB chip is defective.

We connect the small basic controller and we could see the real time data. We couldn't save a Global File.

I'm not familiar with that early style handheld controller, but isn't there a mini SD card that's used to upload Global Folders?

I'm guessing because the firmware in it is not compatible with V4, and can't be updated. Is this correct?

Correct, there is no update for that older style handheld controller. Holley is phasing out the smaller early style handheld controller (LINK). It'll soon be obsolete.
If you choose to update your EFI software/ECU firmware, you'll have to purchase the newer 3.5" LCD Touchscreen unit (LINK). Which is much better anyway!