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VR Sensor needed - Herts
MakeEverything - 25/10/10 at 10:08 PM

Hi There,
I think i have narrowed the fault down to the VR sensor which i want to try and replace with a proven unit if poss.

I am off work this week (half term) so really only have this week to break the back of the work still needed to be done.

Does anyone local have one i can borrow please?


ChrisW - 25/10/10 at 10:17 PM

What engine? I have a zetec one.

Chris


MakeEverything - 25/10/10 at 10:19 PM

Im using a ford one like This and the bracket is made for this, so would like to keep the same if poss. Really, i just want to verify if mine is nackered before spending £20 on a new one.


matt_gsxr - 25/10/10 at 11:00 PM

Have you measured its resistance yet?
The design of a VR sensor is pretty simple, so if it is magnetic, and is not open circuit and not shorted then it is probably fine.

Have you 'scoped the output? Voltage should be a few hundred mV (mine is around 250mV at cranking, and much more with engine running, area under the voltage time curve is constant-ish so as the engien goes faster the pulses get shorter the peak gets higher).

Its just a coil of wire around something that gets more or less magnetized as far as I can tell. Their normal mode of failure is when the crank wheel piles into them. Which is a pretty easily identified fault mode!

I only have motorcycle sensors.

Matt


MakeEverything - 26/10/10 at 07:57 AM

quote:
Originally posted by matt_gsxr
Have you measured its resistance yet?
The design of a VR sensor is pretty simple, so if it is magnetic, and is not open circuit and not shorted then it is probably fine.

Have you 'scoped the output? Voltage should be a few hundred mV (mine is around 250mV at cranking, and much more with engine running, area under the voltage time curve is constant-ish so as the engien goes faster the pulses get shorter the peak gets higher).

Its just a coil of wire around something that gets more or less magnetized as far as I can tell. Their normal mode of failure is when the crank wheel piles into them. Which is a pretty easily identified fault mode!

I only have motorcycle sensors.

Matt


Thanks Matt,

I know what the sensor is, but mine isnt easy to test in situ, given that it is against the bulkhead and between the water pump belt etc. I would have to lean over the engine and through the belts to test it whilst cranking. Im not doing that!

It doesnt appear to be damaged by the trigger wheel, but i dont have an oscilliscope to test it either.

All these reasons are why i want to swap it with a known good unit rather than mess about, but thanks for the reply.