Camshaft VR sensor Problem

[Sprocket]

Hi All, I'm in need of some advice in tracing the fault with my camshaft sensor. I've checked all other sensors and actuators out and this is the only thing that's not working.

This is a Rover VR camshaft sensor that was used on the Non VVC K series engines and the Classic Mini MPI, is similar to the crankshaft sensor. 2 pin connection.

Resistance at the wire ends is ~1200 ohms, which is not dissimilar to the crank sensor at ~1300 ohms (crank signal is good). I should point out here that there are two sensors with a different part number, identical in looks other than one has a white top half, the other is all black. The Classic Mini MPI parts list shows the all black sensor I have as superseded by the other sensor so both should be interchangeable. I have a couple of the later sensors on their way to me.

I've tried reversing the polarity, but still no joy. I don't know what the connector polarity should be, I cannot find information on it.

This is an OEM set up

What I really need to know is how to diagnose whether this is the sensor, the pickup on the cam or is it the ECU? Where do I start? I'm hoping its either the sensor, or the polarity.

[Kamuto]

hook crank sensor in cam input and log it and backwards cam on crank input and you will see where is the problem

[Sprocket]

hook crank sensor in cam input and log it and backwards cam on crank input and you will see where is the problem

  Obvious really 

Thanks

[Sprocket]

Right, I'm still having problems with this 

I have checked the secondary trigger as Kamuto suggested, and with the primary (crank) sensor feeding into the secondary input, the trigger log registers. It is however a different shape log from the primary input, not sure if that is telling me something. That said, the secondary sensor on the primary input i get nothing at all with either polarity which is just the same as it is on the secondary input. I'm getting the same resistance at the ECU wire end on both primary and secondary sensors as they are much the same.

So, i'm after advice on this. This is an OEM set up with the OEM sensors, and is much the same as used on the Rover K series non VVC engines, why won't it work with Vems? Hoping some one might be able to give input.

This is the camshaft trigger set up as installed, it was an original a factory cam, but has had all the lobes machined off as it only drives the oil pump now




This is the original factory camshaft, the secondary trigger pick up is the third lobe from the left, the one with the groove in the middle





This is what is used for both the primary and secondary sensors. The pin sits in the groove in the back of the flywheel, and that groove in the cam lobe.




I have 38 positions I can position the secondary trigger pick up at (number of teeth on the drive pulley), and its currently somewhere near 180 BTDC.





I cant get at this shaft now without dismantling half of the engine, so if I have to do something else, I'm going to have to do something on the head/ camshafts/ pulleys.

Any advice welcome

[Kamuto]

quite interesting sensor, not sure how it works

[Sprocket]

Well, after lots of testing, we have come to the conclusion that having removed the lobes either side of the pick up, it has changed how the magnetic flux in the sensor varies.

We proved the inputs several times, proved the wiring and used five different sensors including the one from the crank and it still didn’t work. Removing the sensor from the engine and still connected to the wiring and ECE waving a screwdriver the trigger logger registered a reading.

For now I’ve decided to hash another sensor targeting one of the bolts on the vernier cam pulleys. We tested that by holding a sensor in position while turning over the engine. I’m just waiting on the sensor and bracket to turn ip that will make fabricating the bracket much simpler.

I now officially hate Minis, and have no idea why I do this to myself😔