Wildguzzi.com
General Category => General Discussion => Topic started by: Kiwi_Roy on July 27, 2025, 09:48:19 PM
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This little pickup is something everyone should have as a spare, if it fails there is NO work around.
The sensor is a weak magnet surrounded by a wire coil, it generates a sine wave signal as the steel target passes close by the tip disturbing the magnetic field.
The ECU uses this signal to trigger spark and injectors
If it gives out there is no easy replacement. I was told that a Fiat one would work but unable to find one here in Vancouver.
If the sensor fails the ECU doesn't know the engine is rotating so it will not turn on the injection relays so No fuel pump, no spark, no injectors.
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https://www.af1racing.com/6389915-oem-aprilia-crank-position-sensor-6389915
This is the same thing for the v7 only from Aprilia at 15% the price.
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Thanks for adding the link Vagrant
Roy
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Roy- along with a lot of folks here- helped me out diagnosing a bad phase sensor on my California a couple years ago.
If anyone needs a depth gauge (the sensor needs to have a narrow gap between sensor and the teeth on the cam gear), I made a simple one from kyvec and a 1/4" rod. Happy to loan it out to anyone. Fits the California, I don't know about the V7 range.
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That sensor is notorious for leaking on big blocks. I took one off years ago to put some gasket sealer in place of the crapy paper one Guzzi uses, and all was well for a bit, but then the bike would just stop running if it went over RR tracks or such. It would eventually start, but it kept happening. Took it to a great shop and they told me I forgot to put the little shims back in, and he was amazed that it would run at all. Ride and learn.
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This is a simple document on fuel injection
http://www.dpguzzi.com/efiman.pdf
Page 13 shows the phase sensor that the air gap T must be 0.6 - 1.2mm tip to the target.
Of course you cannot get a set of feelers in to measure it, here's what I do.
1/ Align the target up with the centre of the hole.
2/ Put a small blob of quick setting epoxy or JBWeld on the tip of the probe.
3/ Bolt it in place with all its shims. (see Note after list)
4/ Allow time for the epoxy set up.
5/ Remove the probe.
6/ Peel the epoxy off the tip and measure it's thickness with my electronic caliper 0.6 -1.2mm if < 0.6 you need to add a shim.
7/ Bolt it back on and go for a test ride
Note: the epoxy won't stick to the target, normally it's oily, if not put a few drops of oil on it before step 3
BTW the efiman pdf is old but if you read it has a lot of useful information on how fuel injection works.
When you turn the key on the ECU closes the injection relay for a couple of seconds (strictly based on time), this runs the fuel pump to charge up the fuel manifold then the pump stops and waits for cranking.
As the bike cranks pulses from the phase sensor on the cam shaft tell the ECU it's cranking over and so it starts the pump starts again by closing the injection relays.
The ECU knows exactly where the engine is on it's cycle because there's a couple of teeth missing, it counts teeth from there firing the plugs and injectors at the appropriate angle.
I hope I haven't confused you.
Roy