shielding hall sensors?

[Roverdose]

starting to wire up my engine from a std loom. uses hall sensors on the crank and cam, neither of which are shielded in the std loom.

do they need to be for the dta or is it ok to leave them as they are?

cheers
Drew

[Jon K]

I would shield them. Use a quality twisted pair, screened cable and connect the + to the DTA input, and the negative of the sensor to sensor ground along with the shielding at the ECU end of the cable. Definitely shield it.

[x30xe]

yes, shield it. Also hall can easily suffer from interference, it is very common.

[VR6Turbo]

I would shield them. Use a quality twisted pair, screened cable and connect the + to the DTA input, and the negative of the sensor to sensor ground along with the shielding at the ECU end of the cable. Definitely shield it.

Both grounds to the generic sensor ground (pin 33) or the crank / cam sensor's own ground?

This is what I find confusing about grounding in general. People often say you must ground here or there and in a specific way but I've never had any issues with noise just following DTA's diagram. I.e:-

Signal - relevant pin
Signal ground - relevant pin
Shielding - Sensor ground (pin 33)

And what about the S80's case ground? Does that go to chassis or pin 33, or battery negative?

A definitive grounding advice thread would be nice

As I say, I've just grounded where I felt seemed appropriate but then I get paranoid when people suggest other ways to do it.

[stevieturbo]

Ultimately all grounds are combined in the ecu, so if all grounding is 10%, then it can become less of an issue, provided you do not create any ground loops.

ie whatever grounds are used, they all run in one direction from stop end, to ecu/ground

But from memory they do ecu the case to one of the sensor grounds.

[Jon K]

I think you mean 100% stevie though 10% would be easier haha

The case is shown grounded to pin 13. So just do what is drawn - crimp a pin on a wire, bring it out 8", splice in a wire with a ring terminal over to the ground post, and then ground that wire to the car chassis.

The hall sensor confuses people - myself included. Its an active sensor. It has a power, a ground, and a signal. The ground on the sensor itself is for its power circuit. So, technically, I would think you'd ground that to whichever ground is respective to your power. Ie., if you are feeding the sensor with +12vdc from the car directly, ground it to car chassis ground. If you are feeding it +5vdc from the 5v supply of the ECU, ground it to sensor ground. Truthfully, as stevie said, if your grounds are right, chassis or sensor ground should work for you. The "signal" is just a short to ground that drains 5v to 0v in the ecu, no + voltage comes out of the sensor.

[VR6Turbo]

Thanks guys, very helpful indeed!

[MSEL]

agree 100% - definitely shield.

OEM looms often do not have shielding as the OEM spends a lot of time developing a car and is aware of any noise issues. They get around this with specific noise filtering in the software in the factory ECU.

When you going changing stuff in the engine bay (coils, injectors, alternators, etc), all this goes out the window.

[Joey]

I believe the best way when using shielded cable, is to take the ground off the shield and drain it away from the ecu plug.