spider

iTrader: (1)

I was wondering exactly what the cam and crank sensors consist of? I haven’t taken one off my car yet, but they’ve been described to me by a Subaru mechanic as a magnet with a coil round them, soldered into the sensor case.

If this is true, what breaks to render them inoperative, and can they be repaired in some way?

I had a hunt about in the various Yahoo groups and came across the following quote from a guy who reckoned he’d fixed one and had no problem for over a year since (don’t know what MY scoob he has):

So, what does anyone think? It sounds plausible to my limited experience (and I know a little knowledge is dangerous! )

Has anyone got a spare, broken sensor they can try this on?

As I say, I’m no expert, but if this is posible and saves us all £100 per sensor, it’s a good thing, right? (Unless you’re a parts retailer, obviously! )

Cheers,
Steve

Pavlo

broken wire I suspect, just inside the case (as reported by Bob Rawle)

replacement probably easiest, although you may be able to use an off the shelf industrial sensor and adapt it to fit.

paul

spider

iTrader: (1)

That's an idea Paul - presumably the sensor is only 'counting' electrical pulses caused by some part of the cam/crank rotating?

Knowing what little I do about these things though, I'd guess there's some specific voltage or similar that the Scooby's ECU expects from the sensors - knowing me I'd fry something.

Didn't know Bob had commented on this before. Is there a link (no pun intended) to his views/comments?

I'd still like to take an old, busted sensor apart just coz I'm like that Most of my toys got put back together again with all the bits when I was a kid - honest!

Cheers,
Steve

spider

iTrader: (1)

Apart from Paul, does anyone else have any thoughts on this?

Fair enough, I could be barking up the wrong tree but I'd have thought it's worth some investigation/experiment.

Anyone got an old cam/crank sensor from a UK MY98 (or thereabouts) they don't want - I'll take it off your hands.

Cheers,
Steve

submannz

Yes they use electro magnetics to sense where the cams or crank is positioned, it would be very difficult to repair them because you would need to get the windings perfect and spaced out the same.

Eprom

Spider
The principle is called the "Hall Effect", The sensor element detects the magnetic flux changes. In simple terms when you move a magnet across or through a coil of wire you induce a voltage into the coil, this signal is then processed by the ECU. There are various types of sensors, solid state being one of them. Would be
interested in the construction of the scooby one. If its the coil type suspect dry solder joints where the cables go into the sensor,
should be able to measure across with a multi-meter to check for continuity.

spider

iTrader: (1)

Submannz, True - wouldn't like to get that dead on just by eye/hand!

Eprom - thanks for the info. I now know what the Hall sender on my old Golf GTi was for!

It seems that the guy I quoted in my first post must have done exactly what you suggest. I presume a 'dry' or 'cold' solder joint is one where the solder's failed/cracked and just needs judicious use of a soldering iron?

I'm curious as to the exact make up of the scoob's sensor. I was thinking that if the coil is encased or held in place with some sort of resin or equivalent how would it break? I guess that vibration must be the reason for failure in these parts.

Must get hold of a broken one and get my junior hacksaw out!