CPS Testing

[DEcosse]

I've been helping a Street Triple owner on another Triumph forum with some diagnostics
I just made the following couple of videos to illustrate how to test the CPS (Crank Position Sensor)
Thought these might be handy to tuck away for future reference.
These were made off my Daytona 955, but should be good for just about any 2-wire CPS

The first is just a couple of basic LEDs (bare ones - can't be 12V!!)
Just connect the two LEDs in parallel but opposite polarity and connect across the CPS; then crank the engine and you should see them pulse alternately

The second is just to use a DMM set to AC V on a 2V scale - you should see ~ 1V AC

(yeah, I know my battery needs charging )

Hope that is a helpful tip for you guys.

 

[Mittzy]

I've been helping a Street Triple owner on another Triumph forum with some diagnostics
I just made the following couple of videos to illustrate how to test the CPS (Crank Position Sensor)
Thought these might be handy to tuck away for future reference.
These were made off my Daytona 955, but should be good for just about any 2-wire CPS

The first is just a couple of basic LEDs (bare ones - can't be 12V!!)
Just connect the two LEDs in parallel but opposite polarity and connect across the CPS; then crank the engine and you should see them pulse alternately

The second is just to use a DMM set to AC V on a 2V scale - you should see ~ 1V AC

(yeah, I know my battery needs charging )

Hope that is a helpful tip for you guys.

One for the vault for sure - thanks Ken

 

[rocketjohn]

Good test...but I have the idea that if the engine starts, the CPS is good. If it don't start...that's when you'd be trying this out.

 

[DEcosse]

.... If it don't start...that's when you'd be trying this out.

Duhhhhhh ............

 

[Hammer]

Any insight as to what getting a higher ac voltage reading means? I'm getting 2.8-3.

 

[Journeyman]

Fighting gremlins right now- you mean if it simply starts then the CPS is definitely good?

 

[CamaroCarl]

Disclaimer: I'm not an expert. I think the crank sensor is like a magnet, just "sees" the steel of the crank as it rotates, sends a signal to ecu, which tells the spark plugs when to fire. If it is bad, or unplugged, you will get no spark. However if you get a piece of steel stuck on it, it will send incorrect signal to ecu, fire plugs at wrong time, or confuse ecu. Have heard of cleaning sensor and fixing issues. If you have a bad connection, it could intermittently lose signal, plugs wouldn't fire every rotation of crank, but I think symptoms would be stalling or no start sometimes.

 

[Gregger]

The crank sensor will pick up swarf from the starter bendix/flywheel engagement process. You could end up getting some metal from those gears meshing (or sometimes not meshing) migrating to the magnet on the sensor which could mess things up as previously posted. It is easy to check and clean.

 

[Journeyman]

The crank sensor will pick up swarf from the starter bendix/flywheel engagement process. You could end up getting some metal from those gears meshing (or sometimes not meshing) migrating to the magnet on the sensor which could mess things up as previously posted. It is easy to check and clean.

I have recently cleaned mine. I'm leaning towards a bad coil, possibly.

 

[idk]

Possibly low tension leads on coils are not tight.