Why does the D2 have a cam and crank position sensor? One would think the computer could figure out one if the other is known. Just curious, I’m not having trouble with either one, just something that popped in to my head.

 

Guessing here but slight variations could reveal addition info about load conditions. Whatever the reason, I'm reasonably certain it was done in F1 first.

 

My guess is that dragging a motor designed in the 50's, into the modern era required some ingenuity as to how you could get modern systems to play nice. Thus requiring both. Just a guess.

 

Motronic 1.3 was the first iteration to require both sensors, beginning in 1987. Advanced engine management principles would make an engine of any vintage run more efficiently, and therefore since all Discos came out after 1987 they would all require both sensors. I don't know enough about Range Rovers to know when they abandoned the previous generation of Motronic which used two flywheel sensors, one for engine speed and the other for position reference, but cam and crank were a carryover from that and likely for those same inputs.

 

GEMS which was used in the 96-99 D1 also had a Cam & Crank Sensor

 

I’ve wondered the same thing, as they are a “wasted spark “ system. I think the engine might run without the cam sensor and throw codes, but I don’t know that for a fact.

 

Engine will run without the cam sensor, but it's rough.

Both sensors are required because the cam turns at half the speed of the crank. Pretty well all modern vehicles have bothm that allows the computer to know whether the engine is on the power stroke or the compression stroke.

 

on my D1 my VSS is failing so I will change that out and for good measure change the crank position sensor at the same time - it is a much less expensive part and prone to failure

i haven't really heard of the cam position sensor failing much - it is the most expensive of the 3 so I will let the original keep going - probably doesnt get the heat and oil crude of the other two so less likely to fail

 

Alex I know most modern vehicles need the cam sensor as they only fire once every two revolutions, just before TDC of the power stroke. I know my GEMS is a wasted spark system (I think the Bosch is too), so it fires every revolution.

 

you know now you will have problems with one of them right ?