Mini Crank/cam advice

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Dundeeguy
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Mini Crank/cam advice

Post by Dundeeguy » Thu May 16, 2013 1:23 pm

Hi guys

No problems to discuss, just a little info/advice on a mini crank and cam waveform I captured.

I'm just starting to grab some waveforms to build up a database, but found the readings from this mini strange. (or at least strange to me!)

This engine has 2 cam sensors, so I assumed they would trigger at exact same time. Seems not. Does this appear normal? Car has no running issues etc, was only in for roll bar bushes :)

Thanks for any advice.

Kevin
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Dundeeguy
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Re: Mini Crank/cam advice

Post by Dundeeguy » Thu May 16, 2013 8:32 pm

All this stuff is new to me, so just trying to gain knowledge etc. I gathered it was ok, otherwise running issues would happen. It's just I expected to see both cams trigger together so was more curious as to why they didn't I guess.

Cheers

Neilcur
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Re: Mini Crank/cam advice

Post by Neilcur » Thu May 16, 2013 9:15 pm

I see in your notes you have put inlet cam and exhaust cam so i take it this model has a sensor for each camshaft?

If that is the case then they will be different as your inlet and exhaust valves open at different times?

Not sure if that is case, just my thoughts!

Neil

mteste03
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Re: Mini Crank/cam advice

Post by mteste03 » Thu May 16, 2013 9:31 pm

Hi,

This is my theory and may or may not be correct.

I guess that was taken at idle, in which case if the vehicle has variable valve timing it would be advantageous to open and thus close the inlet valves later to improve idle.

Matt

Dundeeguy
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Re: Mini Crank/cam advice

Post by Dundeeguy » Thu May 16, 2013 9:36 pm

Yeah, sensor on each cam. I don't think the engine has variable cams, but could be wrong. Customer was on way for car so had to get it off ramp quick. So yeah, your thoughts could be correct.

Main reason I wanted a cam/crank capture is we have a 207cc coming in with running fault (same engine I think) so thought it would be handy to have!

Cheers

Dundeeguy
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Re: Mini Crank/cam advice

Post by Dundeeguy » Thu May 16, 2013 9:38 pm

Matt, our posts crossed. Not too sure if it did have VVT, sorry.

However, all thoughts taken on board.

Neilcur
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Re: Mini Crank/cam advice

Post by Neilcur » Thu May 16, 2013 9:39 pm

Just spoke to a guy that works in a bmw dealership and he said that there is 2 cam sensors for the vvt so Matt was correct!

Thanks Neil

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Re: Mini Crank/cam advice

Post by mteste03 » Thu May 16, 2013 10:15 pm

You should be able to see CAM shaft position change under different engine loads, RPM , and if equipped EGR regulation.

Also Camshaft differences between inlet and exhaust will play part so it depends on the design of sensor pick up I guess to exact relative positions.



Matt

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Re: Mini Crank/cam advice

Post by Mclain » Wed Jul 12, 2017 6:59 am

Very old topic, but might as well reply.
This looks pretty normal to me, for 1 thing.

I have a Peugeot 207 here with a 5FW engine(Dual VVT), based on the same engine you are having in the mini here.
When i compare your signal to mine, it doesnt add up, and i also had this with the 5FX version on a 207 once. The signal is completly inverted to the one from the database. Your crank trigger signal has a long "High" while mine has a long "Low"
Also had this happen to me once with a Peugeot 207 THP with just the single "variable cam".
So thats what struck me as odd. Did you happen to capture the Peugeot data you mentioned in your first post. Like to get to the bottom of this :)

cheers

Michel

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Re: Mini Crank/cam advice

Post by STC » Wed Jul 12, 2017 9:21 pm

This would be easy to explain on an Inductive sensor because it would depend on which wire you probed.

This is clearly hall effect, which is an Inductive Sensor with a PCB (ASIC ?) to digitize (is that a word?) the output.

I can offer 2 possible theories
1. The PCB is configured differently.
2. One sensor starts at 5v and the pulls down the other is at 0v and pulls up.

Having re read this, 1 & 2 above are essentially the same.

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