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B1ack_Mi16

Crank Sensor Issues This Time

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B1ack_Mi16

Well, as I finally seem to have fixed the CAM sensor signal I ran into trouble and misfire with the crank signal.

 

Signal is perfectly good until about 2500-3000rpm, then it starts to misbehave. It seem to be loosing 3 teeth instead of 2 on some occations, see pic below to the very right.

Please ignore that the CAM signal is not behaving on this very occaiton, I did some experimenting with some filtering on it at this point so it is not looking as it should.

 

Trigger_05_zpscrn4k5ne.png

 

Anyway, the loom is completely OE regarding the crank signal, it's a 405 Mi16 2.0 loom I'm using from crank sensor all way back to Bosch ECU plug.

Inside the bosch box the MS3 PRo module card is located and a wire is run from the correct plug pin to the correct input on the MS3 Pro.

 

I would have thought that this should give a good quality signal considering the loom is OE.....

 

Are there any tweaks that can be done to the crank sensor as for the cam sensor, adding some resistors here and there?

Edited by B1ack_Mi16

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petert

No, the crank signal is low voltage AC which gets rectified/filtered by the ECU. Are there any filter options in the software?

 

There are two other options. One, try another oem CAS. Two, change to a hall effect sensor which fits in the same hole. That's what I did, giving a reliable 12V square wave signal.

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B1ack_Mi16

No, the crank signal is low voltage AC which gets rectified/filtered by the ECU. Are there any filter options in the software?

 

There are two other options. One, try another oem CAS. Two, change to a hall effect sensor which fits in the same hole. That's what I did, giving a reliable 12V square wave signal.

 

That certainly could be an option. Which sensor was that exactly?

Anyways there are some filtering settings, so I need to look more into those, however I didn't think it could be this much of a hassle to get the crank signal stable and OK.

My 205 running the Emerald M3D just works out of the box, no adjustments possible.

 

So that's probably the drawback of the MS, much more settings that needs to be looked into.

 

I already tried to change the sensor for another one but the same behaviour.

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opticaltrigger

Hi there,

It is possible that the signal your seeing could be caused by emf generated by the spark plugs.

I'm not saying that it is, but it's definitely worth investigating. EMF contamination in ignition systems can be a serious issue. OEM's go to exhaustive efforts to contain it.

I have no idea of the proximity of the sensor wiring to the HT side of things, but if it's close or the shielding on the sensor cable is insufficient or damaged then it's quite possible for the EMF generated from the HT to upset the signal from the crank sensor.

I used very good quality OFC microphone cable, preferably with a double wall outer shield it's an excellent choice for eliminating it as a problem at least. I guess a couple of meters of it would do so it's not allot of money either.

Not sure what it's temperature parameters are but we use it without issue.

 

Oh, and keep the internal cores as short as possible and the shielding as long as possible.That EMF can be sneaky stuff.

You really can't overdo the shielding.

 

 

All the very best

O.T.

Edited by opticaltrigger

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B1ack_Mi16

After getting a hint at the MS3 forum, and also read the manual once again it states that for 36-1 or 60-2 setups it might be needed to solder in a 10kOhm resistor between the two pins on the VR sensor.

 

First I checked the shielding though, and it goes all the way from the sensor till the Bosch ECU plug, so couldn't really make it any longer.

 

Soldered in the resistor and no sync problems at all. At least not up to 4500rpm which was the highest I bothered of revving it now :)

Edited by B1ack_Mi16

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petert

Glad you sorted it. This is what I use. It has an M12x1.0 thread on outside, so you can vary the height.

post-2864-0-85887200-1483048735_thumb.jpg

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