Hondata

I've to tune a Lotus Elise with K20 Swap. Unfortunatly the ECU is installed in the left/rear corner of the Car. To tune the car it would be nice to have the laptop on the passengers seat :)

I allready tried a HQ USB Cable with 4.8 meters, but when i connect to the ECU it disconnects just a second later :( The ECU and Laptop are ok, they work with any short USB cable. The long USB cable is tested with a Laserprinter and works, too.

How long can the cable be? Will a short cable work, like a 3.5 meters one?
What can i do to get it work over this distance? USB Hub?
Has anyone experience with a long USB cable and KPro?

Thx!

You will get signal degradation when a longer cable is used. The shorter the better. We also do not recommend the use of a HUB.

I use a 10' cable on my car without problems. The issue you have is interference. The longer cable degrades the signal enough to drop the USB packets.

Check your engine grounds and spark plugs.
http://www.hondata.com/techk20swapgrounds.html
http://www.hondata.com/techksparkplugs.html

With the engine running measure current flows to the battery negative from the ground points on the engine and USB cable metal shield. There should be < 0.1mA current flow, otherwise you have a wiring issue or poor ground in the vehicle.