Laptop losing ECU connection after starting

[timlothian]

I have a slight problem with my ECU connection.

I am using an M800 ECU, to an Aprilia SXV 550, with my own wiring loom and relay bank.

The problem: I am yet to get the engine actually running as i am waiting on a sync sensor, but, when I press the start button and crank the engine over for a second or two, it cranks fine but then when I stop a message comes up on my laptop saying the ECU is not connected. Then, to bring back the ECU screen with all my sensors and stuff I have to unplug the usb cable and then plug it back in. Before I crank, the Motec screen is fine, and all sensors give readings, and after I reset the usb all is fine. It just loses connection when I stop cranking.

Have I got a wire missing, or in wrong? Or is it because of a sensor error, such as sync or lambda? Or perhaps is it just because I am not actually ticking the engine over?

As I said, I have not actually started the engine yet, and am waiting on a sync sensor, but just happened to notice this when testing all my systems.

Thanks in advance

[Pascal]

Have 100 resistance on the end of the CAN? There is nice ECU to UTC cable with already preinstalled 100 resistance. Try it. Mine problem was been ALWAYS there. Bad wiring!

[timlothian]

Just to put closure to this. As suggested in the other thread, the root of my problem was the usb extension cable i purchased. From the UTC/UTC cable I added a 3 metre extension, turns out this cable created problems with the computers ability to talk to the ECU.

Next im on the hunt for an amplified or better shielded usb cable.

Any suggestions?