USB communication problems

[2wheels1man]

Hi I'm having a lot of problems with usb communication with the EMU.

I was in a car with a laptop (on battery) connected to EMU with the supplied cable.
I connected fine, but once the car started driving (especially fast driving, it's a race car) the connection dropped and after couple of seconds it came back again.
Sometimes it didn't even come back. I had to unplug the cable and plug it back and it started working again, but not for long...
This was happening the entire session.
The engine ran fine the entire time, so the ECU wasn't loosing ground or power.
When I had the engine on a dyno, I didn't have this problem. Although, the connection droped out a couple of times for a few seconds.
Laptop runs win 7 x64 admin account, EMU ver 1.158.

Also.
I have a desktop PC on my dyno, but it is completely useless as the connection drops out every time I run the engine over 1500 rpm.
When it came back to idle, the connection came back again. This was on one engine with passive coils with non insulated spark wires. (that should not be a problem)
I tried making my own cable, with the shielding disconnected at about half length of the cable, so that the ECU ground and PC ground were not connected, but no change.
Desktop runs win xp 32bit, EMU 1.158.

I also find weird that the metal housing of the ECU is not grounded. (Measuring at the screws of the unit) Is there a reason?

I've tried searching the forum, but didn't really find any solutions...
Any help would be much appreciated, especially with the laptop comms.
Thank you

[Adamw]

Try resistor spark plugs and if your engine has HT leads ensure they are a suppressed type.

[2wheels1man]

The first engine in the car has spark plugs with resistors and coil on plug coils (Denso from Honda K series)

Maybe it would help in the second case, but I ended up using my laptop.
It wasn't 100% but I was able to tune the engine.

But this really shouldn't be an issue for the ECU.
Thanks for your reply.

[RHD]

I find this is a common thing too, i think a lot of the time it is caused by worn USB sockets and the vibration of the car causes a bad connection, try buying a good quality usb lead from a computer shop or using a different USB socket, and try to limit the amount the lead or laptop can move about.

[ihiryu]

I've had this issue with megasquirt. I would do a high RPM pull and it would lose connection.

It wasn't a USB though, I had to use a serial adapter to USB, but the problem ended up being a bad ground. I cleaned off the main ground, and the problem went away.

[2wheels1man]

All grounds are new ring terminals connected to the same point, and like I said the engine works with no problems...
It wouldn't with bad grounding.

I guess I can try to tape the USB cable to the ECU next time

[Bartu]

actually "taping USB cable to ECU" might no be such a bad idea... it's just a usb connection, and it is prone to connection problems when it's moving in the socket.
I also had a lot of issues with usb communication with my laptop. Unfortunately I'm not sure what exactly helped, as I corrected several issues at the same time.

So:
I had problems with both: random communication breakdowns, and high RPM breakdowns.

First of all:
What surely caused issue sometimes, was USB socket in EMU, as my USB cable (original that I got with EMU) was sometime loosing connection when I moved it.
Solved with: zip-tie for USB cable on EMU side. - Random connection issues were gone (most probably).

And then only high RPM issues were occurring (in my case above 4000-4500RPM, if remember correctly):
Most probable solution was "power settings" for laptop, I changed many of them to "full power instead of economy", surely "USB port power settings" were amongst them... At the same time I experimented with different drivers (I will try to look for those i used last, and post link to them, when I find it).

After that all the problems were gone, and I never (in at least 40+ hours of USB connection) experienced them again

[2wheels1man]

Thanks! Great answer.
Will definitely try the zip-tie upgrade

I didn't experience high RPM breakdowns on my laptop, but only on the desktop PC.
When the engine was on the dyno, the ECU nor the cable were moving.
And the connection dropped every time exactly the same. Once I reached 1500rpm with throttle above something like 10%.

I'll try different drivers and an USB analyzer tool and see what happens.

[BigMac]

Try resistor spark plugs and if your engine has HT leads ensure they are a suppressed type.

X2
I had a lot of problems with another ECU which was down to non resistor plugs. I also try and get as many ground wires from the ECU direct to battery neg and ground the coils to the chassis and not into the harness. I think USB is susceptible to interference so I use the USB3 comms cables as they seem better quality with better sheilding

[RHD]

thats a good point, and something a good lead from a computer shop might also help since they are usually much fatter with good shielding and they often have an eddy current suppression block which may help with interference etc.

[BigMac]

Just had the dreaded comms problem with another brand ECU -turns out that it has non resistor plugs and they are a nightmare to change.
Funny thing is that the car tuned in fine for an hour or so and then started playing games and now it just won't connect at all with engine running.
I can only think that the plugs had sooted up due to lots of cold rich starting and idling and then once the plugs cleaned and dried from the full power runs
the interference had to go elsewhere -who knows !