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Hey!

We're a Formula Student team trying to run a Honda CB600F Hornet 2009 engine with the DTA S60 Pro. This is an engine with, as far as we can see, a 16-3 (so 13 actual teeth, 3 missing, photo attached) crankshaft trigger wheel and no cam sensor. Unfortunately, the DTA doesn't recognise the wheel when we run the crankshaft oscilloscope. It does say that it has 13 teeth, but that the wheel has a two teeth gap instead of three, and we also get the unknown crank wheel message.

We've made sure that the polarity is correct as well as connecting the cable correctly to the DTA (the one for a magnetic sensor). We also connected an oscilloscope to make sure that the signal's good and that there's no interference going on and it looks okay to us, attaching photo below.

We're out of ideas now. What else could be wrong?

Thanks!

Update: Apparently the sensor or the DTA doesn't like low RPM (I presume), cause by removing the spark plugs we got it to report 3 missing teeth. But it still says unknown crank wheel, if that's a problem? What now though? Do we need a better sensor?

Crankshaft oscilloscope (sorry for the bad picture)


Picture of trigger wheel:


Measuring with oscilloscope:

Presumably you have configured the wheel correctly in general engine settings ?

The scope trace looks to be a solid performer ?

stevieturbo wrote:Presumably you have configured the wheel correctly in general engine settings ?

The scope trace looks to be a solid performer ?

Yeah I forgot to mention that, it's correctly configured in the settings with teeth, missing teeth, flywheel mode 0 etc apart from the sensor position angle which we were thinking of getting from the crankshaft oscilloscope function. The general settings shouldn't affcet the crankshaft oscilloscope though, should it?

But apparently the sensor or the DTA doesn't like low RPM, cause just now we got it to report 3 missing teeth by removing the spark plugs. That doesn't really solve our problem though. Do we need a better sensor or what's an easy solution to this?

It seems to be a common problem with bike engines in general.

It must be slow cranking speed which yields a low trigger voltage.

In part, that could be one for Alex too, as to whether the trigger voltage thresholds will ever become adjustable ?

If you have an option of fitting a hall sensor, that should be more reliable. Or create a system that turns the engine over faster when cranking.

So what's the problem it looks like its ready to run, I get the same confusing message on my engines. Or are you getting no spark, for now guestmate the sensor position.

That should work correctly.
The oscilloscope is a best guess estimate, it simply looks at the signal from the crank sensor, and tries to work out what's there.

Make sure the ECU is synchronising:

stevieturbo wrote:It seems to be a common problem with bike engines in general.

It must be slow cranking speed which yields a low trigger voltage.

In part, that could be one for Alex too, as to whether the trigger voltage thresholds will ever become adjustable ?

If you have an option of fitting a hall sensor, that should be more reliable. Or create a system that turns the engine over faster when cranking.

So a hall sensor isn't as dependant on the rotational speed?

Rob Stevens wrote:So what's the problem it looks like its ready to run, I get the same confusing message on my engines. Or are you getting no spark, for now guestmate the sensor position.

Alex DTA wrote:That should work correctly.
The oscilloscope is a best guess estimate, it simply looks at the signal from the crank sensor, and tries to work out what's there.

Make sure the ECU is synchronising:

It's not synchronising when we've got plugs mounted (even with a newly charged battery), which I guess is because it only reads 2 missing teeth and that doesn't match what we've put into the general settings. I do think it synchronised when we cranked without plugs though because we got an rpm reading (I wasn't present at that time).

It may be the 3 missing teeth are the issue. As each tooth is at 22.5 deg spacing - angular distance between last tooth and first tooth is near 90 degrees so the ecu doesn't get a 'countdown' or however it works ! ! ! - i'm guessing here - you may have guessed!
Its a strange oscilloscope trace and seems to show variation in frequency (rotational speed) and amplitude (like variation in tooth / sensor height?)

Trace looks normal ?

amplitude of the trace will vary with rpm and a VR sensor, hence each time as a cylinder is on compression the trace gets a little wider apart and lower amplitude.

Although the actual scope trace does look a good strong clean signal. Although there is no voltage scaling provided.

Does the ECU synchronise, and then throw lots of crank errors, then lose synch again?