My obd1 p28 S300 was working perfect for about 3 months. But when i go to datalog the red flickering led in the usb port comes on but goes off randomly at any time. Then i press datalog again, and it does not work.
IN a nutshell. My S300 datalogs sometimes, its random. i did a test usb on it which was sucessfull once. but sometimes i test it and it gives me error message (unrecognised PID).
So i turn off ignition (OFFLINE) and start again then it datalogs again but only for a second and the green led in the ECU stays on.
The ecu was socketed by hondata i bought in through church automotive tuning CA.
ALSO sometimes i can upload a new maps. sometimes i cant so i restart with ignition and it then allows me upload or download.
It seems like a bad connection but the laptop always shows on line or offline.
Its a problem with transferring data i think could it be my laptop??

If I enter device manager the (Hondata S300 ECU) file under Serial connections is perfect. It states this device is working perfect>
all help appreciated

 

sounds like your having a problem connecting and staying connected. ok well my car is wire tucked and i had the same problem. so i added 3 extra engine grounds and 1 to my m&w box PROBLEM FIXED. so i hope this helps you

 

thanks for your reply but i have a lot or earth leads on my head, block, intake and tranny.
I think it might have something to do with EMI or else my laptop's power supply. Still didn't fix this problem. Trying to find another laptop to check it with.
I came across this problem when trying to get the ecu and distributor in sync with the (set Timing )option. anyone else have a problem similar to mine??

 

is J12 cut in the ECU?

 

yes it is . i solved my problem.
My lock-up for the car has an electric fence unit in it,
THis was causing extreme EMI.
When i cut the power to the electrified fence the Ecu dataloged perfect.
Funny i know!!

 

EMI is a bitch!