Reply To: GV650 FI 2002 – REGULATOR / RECTIFIER Instant overheat
Hey,
So it took me some time, but it seems to have been the ignition coil or plug. I measured both in cold and hot, and they always measured fine for some reason, within the specs. But I connected my oscilloscope to the ignition coil’s ECU signal and pick-up signal and R/R amps output, and after that I could see quite clearly that at the exact moment one of the coils fired, the amps dropped to 0, meaning one of the coils was shorting and required more amps than the R/R supplied, which dropped the whole system to 0 amps. This also caused the headlight to flicker for that moment. Now I got NGK plugs, Tourmax IGN 303 (the ones on that Suzuki you mentioned) ignition coils, and NGK spark plugs, and now the problem seems to have been fixed. I ran the bike for over 30 minutes at idle, and it did not die, which was until now the longest time it ever ran.
So for now that is good, but one thing that bothers me a bit is the FI lamp and dealer mode, as both don’t seem to do anything. I disconnected the intake air pressure sensor and temp sensor, and in the manual it says it should show an error via code in dealer mode or blinking of the FI lamp, but the lamp never lights up. Also, on bike start it never turns on. I also checked the PCB itself, injected 3.3V to the FI lamp, and it worked, so the LED on the PCB of the speedo seems to still work.
Also, one other thing I am unsure about is the fuse on the R/R, as the bike’s main fuse is 30 amps. After doing a test and turning everything on that is possible, I got at high RPM to a usage of 20-22 amps, so for now I swapped the 20-amp fuse at the R/R to 25 amps to be sure. Theoretically, the Shindengen should be fine with 30 amps steady, but I would rather like to have a bit of a safe buffer. But as you said, the 15-amp fuse on the R/R should work, so I’m not sure what is going on and if that is normal, as it seems like the usage is steady now, just that it’s steady at 20 amps.
But for now it seems okay. I will do the normal service parts for now, like oil and air filter, and will see after a test drive if maybe I get some errors or the FI lamp to work.
Maybe you have some recommendations from your experience with the GV650, if that 20 amps makes sense on the R/R, or if it could still be worth checking for issues with the harness. I did check most of the wires and voltage drops and found only one big drop on the headlight fuse holder, which I replaced, and now it is near 0V of voltage drop instead of like 0.3V.
Also, big thank you for all the help and recommendations.