OP
OP
You guys have been a big help and moral support. I will document with pics and text how things go when I go the transplant in early August.
Changing the crank position sensor tips
- Thread starter Coyote Chris
- Start date
You guys have been a big help and moral support. I will document with pics and text how things go when I go the transplant in early August.
It never came on
Not sure about how it all works. With the engine running it may just need the camshaft position to continue running. Maybe it wants the crank position sensor for starting to give more pulses at the slower starter speed.
Or it could just be some of that magic stuff.
Arknt
Mike - Your "remembery" is fine.
There is no sensor on the end of the camshaft. Those of you who've done valve clearance checks and had the cylinder head covers off know there is nothing electronic on the end of the cams. As far as I can recall, only one Honda (in modern times) had such a device and it was only fitted for one year model. It was a Shadow with the large engine around 1985-86 and the next year they reverted to the old system of using crank position which is far more accurate.
In the olden days, the points were always driven by the camshaft but when they switched to electronic ignition, it all changed.
There is no sensor on the end of the camshaft. Those of you who've done valve clearance checks and had the cylinder head covers off know there is nothing electronic on the end of the cams. As far as I can recall, only one Honda (in modern times) had such a device and it was only fitted for one year model. It was a Shadow with the large engine around 1985-86 and the next year they reverted to the old system of using crank position which is far more accurate.
In the olden days, the points were always driven by the camshaft but when they switched to electronic ignition, it all changed.
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Correction, the NT does have a camshaft position sensor, it is in the rear bank cylinder head, and there is a trigger wheel bolted to the sprocket at the camshaft. The sensor itself is installed in a hole in the front of the cylinder head, somewhat facing the middle of the V. I have a picture of it somewhere on a computer that I could track down and post on this forum.
I did all the NT valve adjustments myself and it's clearly visible when you have the rear cylinder head cover off. As far as the engine being able to run with a missing crankshaft position sensor signal, I suppose theoretically it's possible, but the ECM in the NT is not that sophisticated. I'm pretty sure it needs a valid and proper waveform from both the cam and crank sensors to run properly.
Bottom line is, if you have a failing crank sensor you definitely need to replace it, it's better than being stuck by the side of the road with a non running bike.
I did all the NT valve adjustments myself and it's clearly visible when you have the rear cylinder head cover off. As far as the engine being able to run with a missing crankshaft position sensor signal, I suppose theoretically it's possible, but the ECM in the NT is not that sophisticated. I'm pretty sure it needs a valid and proper waveform from both the cam and crank sensors to run properly.
Bottom line is, if you have a failing crank sensor you definitely need to replace it, it's better than being stuck by the side of the road with a non running bike.
Found it. So, the sensor itself is the black cylinder next to trigger wheel, right side of picture, with the metal peg on it. The fingers on the trigger wheel pass by it and generate a waveform. Depending on which side of the wheel passes the sensor, 1 or 2 fingers, tells the ECM which ignition coil and injector to fire, front bank or rear bank.
Honda used a cam pulse generator for 1 year on the 1986 VFR. It also had 2 crank position sensors.
What could go wrong.
Well, hell 
, my remembery ain't so hot after all. Truthfully, in doing the valve adjustments over the years, I can't recall ever seeing the CMP sensor. In looking at the schematic, it works in tandem with the CKP sensor and informs the ECU which coil to fire and which injector to pulse. Thus it appears that in the ECU logic, the CKP only verifies rotation and provides the RPM input.
Mike
, my remembery ain't so hot after all. Truthfully, in doing the valve adjustments over the years, I can't recall ever seeing the CMP sensor. In looking at the schematic, it works in tandem with the CKP sensor and informs the ECU which coil to fire and which injector to pulse. Thus it appears that in the ECU logic, the CKP only verifies rotation and provides the RPM input.Mike
My remembery is not all that dependable. I need to verify stuff with places like partzilla.
Looking at the multiple evenly spaced points on the crank end that help the CKP sensor generate pulses it must only be an RPM input to the ECU like Mike said above.
What can really confuse my head is the different configurations different manufactures and bikes use to basically end up with the same end result.
Arknt
Looking at the multiple evenly spaced points on the crank end that help the CKP sensor generate pulses it must only be an RPM input to the ECU like Mike said above.
What can really confuse my head is the different configurations different manufactures and bikes use to basically end up with the same end result.
Arknt
Yes, the CKP sensor does inform the ECM of the crankshaft RPM, but the trigger wheel also has a spot on it that has a missing tooth. The ECM picks up the missing pulse, and from that information it can determine the crankshafts relative position in degrees from top dead center (TDC). Once the ECM knows the crankshaft position in degrees, working together with the cam sensor, it can calculate ignition timing and injector pulses before TDC for each cylinder. Of course the timing and duration of these outputs vary, based on the analog inputs too such as throttle position, coolant and air temp sensors, manifold pressure, and so on. Basically the ECM spends its whole life doing math.