What does the crank angle sensor do? What tools are needed to test to see if it's working?
Also, how do you test the igniters under the valve covers?
Crank Angle Sensor
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Q45tech
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- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
The CAS has two separate systems coupled to a common shaft.The one for a V8 produces a square wave pulse for every degree of rotation [360 total] and another system produces a pulse evey 90 degrees of rotation.On both systems the 0 degree pulse is wider [usually on for 8-10 degrees.Think of a light bulb shinning thru a wheeled slot, with a photocell and squarer circuit.
http://tar.home.sprynet.com/page3.html
When the 1 degree pulse circuit fails [rarely] the ecu tries to work with just the 90/120/or 180 pulse [8, 6 or 4 cylinder engine] but because it is not accurate enough the rpms are limited to 2,000-2,500 for safety.
http://tar.home.sprynet.com/page3.html
When the 1 degree pulse circuit fails [rarely] the ecu tries to work with just the 90/120/or 180 pulse [8, 6 or 4 cylinder engine] but because it is not accurate enough the rpms are limited to 2,000-2,500 for safety.
... works in priciple just like a computer mouse.
To test it, pull it out but leave electrically connected. Turn the key to "on" and slowly turn the CAS rotor. You should hear the injecotrs clicking as the ECU activates them in turn.
Of course the ECU will complain if it thinks the CAS is broken, so this test is rarely necessary. If the ECU is complaining about the CAS, check all the wiring harnesses first, before replaceing it.
To test it, pull it out but leave electrically connected. Turn the key to "on" and slowly turn the CAS rotor. You should hear the injecotrs clicking as the ECU activates them in turn.
Of course the ECU will complain if it thinks the CAS is broken, so this test is rarely necessary. If the ECU is complaining about the CAS, check all the wiring harnesses first, before replaceing it.
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
After years of use sometimes the bearings fail and produce a rusty coating on the slotted wheels . This can cause a drop out of signals in some sectors........usually if there are not more than 6-8 drop outs per rpm the ecu can recreate the pulses and not lose time.
The Consult shows two rpms one derived by reading the CAS and the other from the AT turbine sensor.
The Consult shows two rpms one derived by reading the CAS and the other from the AT turbine sensor.