Jason89s4

On my 89 S4 I replaced the Hall Sensor and you do not have to touch the timing belt. In fact you don't even take the cover off.

The hall sender plugs into the backside of the RH distributor cover. You can see the pigtail come out of the backside. The pigtail plugs into a wire coming off of your engine harness across the top where your air tube will be hiding it--standard Bosch-style plug.

There iare two 8mm allen bolts holding a bracket onto the backside of the distributor aluminum cover. It has a bracket where the plugs are "stored" but I couldn't get mine to go back in there as you will see in the pics. The bracket also keeps the plug of Hall sender in place. The Hall sensor is underneath it. Removing the bracket/cover is a chore and I ended up using extensions all the way back near the H20 reservoir for a long horizontal reach to the allen bolts. (you will see when you get to it--unless you want to start removing the hard fuel line to get access.)

Two pics attached. The first picture is looking straight down with cam cover at the bottom, RH backside of dizzy cover on the left. The shiny bracket is holding the Hall sensor hiding underneath it. (You will see my allen bolt is a shiny new silver--the original was almost stripped after the job.) That plug in the pic is the connection. Second pic is taken further out, leaning over the fender area, for perspective. The cadmium line in both pics is the hard fuel line that will be your nemesis for access and sight lines.

If the sender is still in place and it is just the plug that needs replacing you can get a new one from Roger at 928srus.com and simple splice it into the wiring.
Jason

worf928

You seem convinced that something's been replaced. I see no evidence of this.

This picture shows the factory-correct routing of the front main engine harness, its clamp to the front lift loop, coil ground, the hall sensor and its branch off the LH. It should tell you everything you need to know in terms of why the gray branch gets pulled out with a belt job unless you are very very careful.


Your missing front lift loop makes it easier. But, if you want to do it right ...

... you need room to work.

Also, just because YOU were able to remove the Hall sensor in situ, doesn't mean that it will work on any random S4+ motor. There are a lot of variances in how the bolts for the sensor and corners of the cam cover come together. I have seen motors where the cam cover would not come off without first removing the Hall sensor and motors where the Hall sensor could not be removed without taking off the cam cover.

Doing the Hall sensor en passant with a timing belt, by removing the belt backing plate from the head, works every time regardless of manufacturing tolerances. And, you have room to wind the new Hall sensor into the bracket which keeps the connector from getting damaged due to vibration or engine movement.

All of these (crumble-to-dust) shielded 3-pin connections (knock sensors, CPS and Hall sensor) have brackets for the connectors. I for one, think Porsche's engineers did that for a reason.

FredR

Convinced is the wrong word - puzzled is more appropriate- the OP said he replaced a connector after one fell to shreds [as they do when touched in the old and knackered condition] so my presumption is that he replaced that connector- what else could it be?

Personally I would not try replacing the Hall sender working from behind unless I was absolutely desperate. Doing it with the timing belt and sprocket off is the sensible way to do it. Indeed change out is on my radar preemptively for the next time I have the timing belt off. At least I have ST2 to tell me mine is still working OK .