Reluctor ring coating.

[Jetjockey]

Hello.

Would anybody here know if the rubber coating on the crankshaft reluctor ring is what gives it its magnetic qualities and causes a pulse in the crankshaft sensor?
I’m getting a reported “zero rpm” and “failure to sense the crankshaft sensor within one second of turning ignition key” error and a resultant engine start failure. There has been a persistent oil leak which has covered the reluctor ring and appears to have stripped off the rubber coating around its outer rim.
The crankshaft sensor has been replaced with a new one and the wiring to the ECU has been checked and is OK.
Still the diagnostic “live data” is showing no engine rotation whilst cranking.
Oh, and all supplies and grounding to the crank sensor (+5v) is present and correct.

Any ideas or thoughts gratefully appreciated.

Many thanks.

[Hell Razor5543]

I recall, several years ago, visiting Savoy Garage up in Preston. They had be scratching their heads over (if my memory is correct) a Xsara Picasso with an ABS issue. It turned out one of the magnetic rings had a hairline fracture, which meant it wasn't working properly. It took them ages to find out what the problem was.

[Jetjockey]

Ahhh! Had that one many times. Easy to spot.
However, this non starter has my mate really scratching his head. He called me to look at it yesterday after fitting the new crank sensor and getting nowhere. I’ve checked all the supplies, even on the sensing wire to the ECU (PCM), and they’re all as they should be except:-
When cranking, the sense voltage never gets above about 0.7volts, I would have expected more normally.
I’ve used a logic probe on the sensor output (scope battery flat) and it toggles high/low during cranking.
However again...... the signal isn’t big enough to toggle the logic tester at the ECU end. I’m thinking that the signal is not big enough due the magnetic coating coming off the reluctor ring? The wiring is fine.

[GiveMeABreak]

Did you buy an original replacement part or an aftermarket jobby?

[Jetjockey]

Hi Marc.
I didn’t buy the replacement but it’s aftermarket, however, another sensor has been fitted taken off a known working engine and it still won’t start.