The Autonerdz Community Forums

The Autonerdz Community Forums
https://yabb.autonerdz.com/cgi/yabb2//YaBB.pl Picogroup Area (contact administrator for access) >> Picogroup Motorcycle Discussion >> Timing Issue https://yabb.autonerdz.com/cgi/yabb2//YaBB.pl?num=1670989091 Message started by James H on Dec 13^th, 2022 at 7:38pm

Title: Timing Issue
Post by James H on Dec 13^th, 2022 at 7:38pm

Aprilia V Twin. Some waveforms attached. Has VRS CKP sensor and no cam sensor. Timing is erratic and all over the place. The CKP is noisy and have not seen that before even though I can't see it being a problem. I have a waveform from a known good running same model bike and the CKP signal looks much cleaner. The kicker is I have a new sensor which is just as noisy as the old one so I can't figure out what would cause the noise. Any thoughts?

https://yabb.autonerdz.com/cgi/yabb2//YaBB.pl?action=downloadfile;file=CKP_001.psdata (8680 KB | )

https://yabb.autonerdz.com/cgi/yabb2//YaBB.pl?action=downloadfile;file=Sec__CKP__ICP.psdata (9028 KB | )

https://yabb.autonerdz.com/cgi/yabb2//YaBB.pl?action=downloadfile;file=Sec_V__CKP__ICP__Timing_Problem.psdata (12309 KB | )

Title: Re: Timing Issue
Post by autosparky on Dec 14^th, 2022 at 12:17am

I don´t claim to know anything about bikes so it´s just something I spotted.
It´s definitely electrical noise. As starter disengages the noise goes away.
The noise may be generated by something that produces a frequency or could even be a earthing fault somewhere.
Only advise I can give is start unplugging stuff that buzzes like idle motor.

Also your setup for timebase could be better, like to see a longer "movie" rather than a "snapshot"

Screenshot_2022-12-14_210351.png (426 KB | )

Screenshot_2022-12-14_210829.png (430 KB | )

Title: Re: Timing Issue
Post by Sam M. on Dec 14^th, 2022 at 2:36am

autosparky wrote on Dec 14^th, 2022 at 12:17am:

The noise may be generated by something that produces a frequency or could even be a earthing fault somewhere

+1 with what Autosparky is saying.

I had similar interference this year on a fuel tank pressure sensor causing an EVAP code. My root cause was Amazon bought LED replacement headlamp kit. I would classify the kit as "cost-effective" ::) and when the LED headlamps were on, any nearby analog sensors had similar noise.

Hope this helps.

Title: Re: Timing Issue
Post by StitchB on Jan 23^rd, 2023 at 7:44pm

james, Larry here and have not talked in a while, hope life is good.

Actually the noise IMO does not seem to relevent to me.

I guess the question is why is it firing in odd places. Just my gut, but would in this case think PCM and a driver issue, or noise in the PCM.

Might PM you on some adivce on a Harley with lots of mods.

Larry