just wondering if anyone has the same problem as me.
my hondata s300 has a once in a while problem that occurs for datalog.
i will hit the datalog button but it does not work. the bottom screen says datalog but none of my functions work. i have to keep closing and reopening my hondata software and it will work. any has this problem? there are times that datalog will work and other times does not. any help will be greatly appreciated. thanks

Use OEM Honda wires and resistor type spark plugs, move ignition CDI box far away from ECU, Use the USB cable that came with Ferrite cores, make sure on-board datalogging is disabled if your trying to do real time datalogging. The ECU is pretty sensitive to EMI - (Electromagnetic Interference) Adding some more grounds from engine to chassis doesn't hurt either.

thank you very much

iam curious did this work?? because iam having similar problems

i have used a better quality usb cable and it has not been acting up so far

Mine was a voltage issue bought a new battery and never had a problem since.

you can also try grounding the ecu case if you just have it sitting on the floor

The ECU case has nothing to do with a ground. Nothing inside the ECU grounds to the case and you should never have a ground which loops back to the USB port via the case. This will just burn out the electronics.

DO NOT GROUND THE CASE.

i guess you wouldn't want to bolt the ecu case to the car then as this would ground the case =P guess every honda out there with an ecu bolted down from the factory should have burned out.
where do you idiots come from with this stuff.

lol, there you go Artie..

He was implying that the ecu board is not grounded to anything & shouldn't be along with the USB cable.
Grounding the ecu case/mounting it will make absolutely no difference as there is no contact between the circuit board and the ecu case.

Were you using the usb cable that came with the s300 system?

Every time I have seen this issue it has been because the customer has aftermarket spark plug wires. Install a set of OEM honda spark plug wires. If this doesn't help, make a better ground between the engine & the chassis using 4 gauge wire etc. Also add a ground between the battery and the cylinder head. This has worked for me every time.

grounding the outer case will reduce emi passing through the case. this is why high powered transmitters are put into a grounded cage, or electronics that are sensitive to magnetic fields are put into a cage or metal box and typically grounded. may want to read about Michael Faraday

Let's call the myth busters on this one lol.

No need...Michael Faraday discovered this back in the 1,800's.....read about faraday cage and the new modern uses of it in things like mri machines and transmitters and recievers....even your simple cell phone has them inside to isolate the transmit and recieve sections of your phone. the ecu case itself is considered a form of faraday cage.

i have fixed this problem by using a high quality usb cable. the previous usb cable i was using was just something i bought at the $1.50 store because i misplaced my hondata one. now that i bought another quality usb cable, it has been working like a charm everytime i press the datalog button. thanks for the advice everyone