Honda CB600F Hornet - Unknown crank wheel

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mansson
Posts: 4
Joined: Sun Apr 23, 2017 11:57 am
ECU Model: S60 Pro

Honda CB600F Hornet - Unknown crank wheel

Post by mansson »

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:
Last edited by mansson on Sun Apr 23, 2017 3:14 pm, edited 2 times in total.
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Honda CB600F Hornet - Unknown crank wheel

Post by stevieturbo »

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

The scope trace looks to be a solid performer ?
mansson
Posts: 4
Joined: Sun Apr 23, 2017 11:57 am
ECU Model: S60 Pro

Re: Honda CB600F Hornet - Unknown crank wheel

Post by mansson »

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?
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Honda CB600F Hornet - Unknown crank wheel

Post by stevieturbo »

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.
Rob Stevens
Posts: 1247
Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: Honda CB600F Hornet - Unknown crank wheel

Post by Rob Stevens »

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
Posts: 1622
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: Honda CB600F Hornet - Unknown crank wheel

Post by Alex DTA »

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:
mansson
Posts: 4
Joined: Sun Apr 23, 2017 11:57 am
ECU Model: S60 Pro

Re: Honda CB600F Hornet - Unknown crank wheel

Post by mansson »

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).
katana
Posts: 455
Joined: Sun Jan 27, 2013 6:08 pm
ECU Model: S60 Pro
Firmware Version: 29

Re: Honda CB600F Hornet - Unknown crank wheel

Post by katana »

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?)
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
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Location: Norn Iron

Re: Honda CB600F Hornet - Unknown crank wheel

Post by stevieturbo »

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.
Alex DTA
Posts: 1622
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: Honda CB600F Hornet - Unknown crank wheel

Post by Alex DTA »

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