Speed or Position Sensors
These type of sensors tells the ecu the position of the component. This reacts to the change in speed of the component example the crankshaft sensor and the camshaft sensor.
I got an inductive type distributor and visually look in good condition. No damages or anything. Did a resistance check on the G pickup coil and showed 243 ohms on my multimeter. Manufactures specifications says it should be between 185-275 ohms so our reading shows that our g pickup coil is within specifications. The NE pickup coil had a resistance of 486 ohms and specifications tells us that it should be between 370 - 550 ohms therefore out NE pickup coil is within specifications.
I then checked the air gap between the pickup coil and the reluctor tip with a brass feller gauge. I got 0.203mm which is within the specifications. So i didn't have to adjust it.
I Then connected an oscilloscope and spun the dizzy by hand and got an AC wave pattern.
A - reluctor tip is getting closer to the coil therefore air gap gets smaller and the magnetic field is increasing.
B - Air gap is smallest here and full magnetic saturation of the pickup has reached. The reluctor is lined up with the coil.
c - As the reluctor moves away magnetic field collapses across the coil and induces a voltage in the opposite direction. Back EMF.
D - reluctor tip moving away from the coil so voltages goes back to 0v.
E - Peak to Peak voltage (2.2v)
We connected the distributor on 2 channel and saw the wave form of both the NE and G signals when we turned the distributor. I have shown the peak to peak and time on the graph.
On car Crank Position Sensor (CKP)
The crank position Sensor is also know as the rpm sensor. I back probed the RPM signal wire and connected my multimeter on AC volts. Red probe on the signal and black probe to ground. Then i started the engine. I got a reading of 2.656V. As i ireved the engine to about 2500 rpm the voltage increased to 6.95V.
Then i switched the the mulitmeter to read DC volts. At idle speed the the voltage was 0.407V. Then i reved the engine to about 2500 rpm, the voltage increased to 1.341V.
I sthe switch the multimeter to read hertz. At idle i got 0.456k Hz. As i reved it up to about 2500 Rpm, it increased to 1.925k hz.
The Hz showed a more exact reading on how the rpm sensor working.
My engine had a magnetic pickup type crank sensor. The crank sensor is located inside the distributor and tells the ecu where TDC is. The crank sensor has one tooth to tell the position. This generates Ac voltage. As the speed increases the frequency and amplitude increases.
The air gap wrongly set on the pickup could upset the signal going to the ecu. There could be an open circuit somewhere in the wiring. If the ecu doesn't know the position on the crank shaft,the engine will crank but will not start.
On Car Cam Position Sensor
Our cam position sensor was inside the distributor.Thsi was also a magnetic pickup type.
I back probed the signal wire and connected the red probe of my multimeter to the signal and grounded the black probe. I got readings with different settings on the multimeter revin the engine.
DC volts - 57.5mV - 67.2mV
AC volts - 0.95V - 3V
Hz - 17.9Hz - 6.7 Hz
duty cycle - 75% - 91.4%
Good measurements were the Hz reading and the Duty Cycle. It gradually increased and decreased as the engine RPM increased and decreased. With Duty Cycle we saw as the engine reved the the pickup coil was sending out voltages faster so the percentage it was working (sending out voltages) was more.
This is the same as the crank sensor but the reluctor wheel has more teeth on it.
No comments:
Post a Comment