ENgine starts with half sync randomly

[Josu]

Hi!

I am using a MS3 Pro in a Yamaha FZ6 engine with fully sequential and coil on plug.

Around two thirds of the times I start the engine, it starts in half sync mode. My signals are good and I cant recognize what is the problem.

Here you can fin attached the datalogs of one of those startings in half sync.

Any idea what can be the problem? Thanks a lot, this forum is amazing!

[Josu]

I have changed the number of pulses to skip during starting from 3 to 9 and aparently is solved. However I havent test it more than around 7 or 8 startings. I hope that was the problem.

[slow_hemi6]

Isn't it supposed to start in half sync (wasted cop) until the cam sensor syncs up. This way it actually fires faster when starting and is therefore not cranking on the starter as long. Sometimes the cam will be very close to giving a signal and it might seem to start in full sync but it would be less frequent.

[billr]

Are the crank and cam sensors stock Yamaha, VR or Hall or opto?

[Josu]

Slow hemi6, the engine when starts in half syn it is true that it was doing it extremely fast and it was never getting full sync. In the other way around it was the same, if the engine started in full sync it was never lossing it or going to half sync.

Billr, the crank sensor is a VR and is the stock one. The cam sensor is a hall type and has been isntalled afterwards since the FZ6 comes with wasted spark and semi sequential from factory.

Another day testing and still no problem so I assume that the probem was to atempt to start too fast.

[billr]

What manufacturer and P/N for the cam sensor?

[Josu]

I dont know what o you mean with thw P/N. If is the part number what you mean is this one: 1GT101DC . The brand is Honeywell

This is the sensor datasheet: http://www.tme.eu/se/Document/87cdfa44b ... t101dc.pdf

[billr]

That's the P/N (part number) I was asking for. After seeing the P/N, I don't think the issue I was considering is worth discussing.

[Josu]

Hi I put this topic up again because I am having the half syn issue very often now again. Any idea of what can be the problem?

[Josu]

Can it be a firmware problem? I am using the 1.2.4. Should I update it? because I read in another post with the same issue that he solved it by updating the firmware.

[Matt Cramer]

The cam signal is very close to the missing tooth - if it triggers right on the missing tooth, it won't sync, and this may happen sometimes. Try triggering off the opposite side of the cam signal - if that triggers earlier, you're good to go, but if it triggers later, you may need to move the cam sensor instead.