CAS/no start troubleshooting
10-07-11, 04:40 PM
#1
CAS/no start troubleshooting
I'm getting no spark. I tried ohming out the CAS wires, but I'm not sure if I'm doing it correctly.
To check if the CAS wires are good, I ran a wire from the ECU Plug - 1T, 1Q, 1N and 1P and tested against the wires in the CAS harness(the other end of those wires). They all tested good respectively, so I know there are no breaks in the wires from the cas harness to the ECU harness.
..yet I have no spark.
What am I missing?
To check if the CAS wires are good, I ran a wire from the ECU Plug - 1T, 1Q, 1N and 1P and tested against the wires in the CAS harness(the other end of those wires). They all tested good respectively, so I know there are no breaks in the wires from the cas harness to the ECU harness.
..yet I have no spark.
What am I missing?
10-10-11, 07:54 AM
#3
You place one meter lead on pin 1N and the other lead on 1P and w/key to off it should read between 110 to 220 ohms. Do the same thing for 1T and 1Q (Both are done w/the CAS plugged in at the engine bay but the ECU plug is to be unplugged). Also make sure the B/Y wire at the leading coil has 12 volts w/key to on and that the B/W wire at the Green check connector w/four wires near the leading coil has 12 volts w/key to on.
10-10-11, 09:39 AM
#4
You place one meter lead on pin 1N and the other lead on 1P and w/key to off it should read between 110 to 220 ohms. Do the same thing for 1T and 1Q (Both are done w/the CAS plugged in at the engine bay but the ECU plug is to be unplugged). Also make sure the B/Y wire at the leading coil has 12 volts w/key to on and that the B/W wire at the Green check connector w/four wires near the leading coil has 12 volts w/key to on.
To check for spark, I pulled the plug, grounded it and had someone crank it over.
10-10-11, 11:11 AM
#5
Disconnect the White two wire plug from the leading coil and measure the voltage on the Green/Yellow wire w/key to on as the engine is turned over by hand which is done by turning the alternator pulley. The voltage should go from 5 volts to 0 volts in a very slow but repeated manner. This would indicate that the ECU is sending the firing signal to the coil. And make sure the coil is bolted firmly to the fender as this is how the igniter finds a ground.
And when checking for spark remove the spark plug wire boot from the leading coil and rest it right up against the coil bore to check for spark as this removes the wire and the plug from being the root cause for the lack of spark.
And when checking for spark remove the spark plug wire boot from the leading coil and rest it right up against the coil bore to check for spark as this removes the wire and the plug from being the root cause for the lack of spark.
10-10-11, 11:58 AM
#6
Disconnect the White two wire plug from the leading coil and measure the voltage on the Green/Yellow wire w/key to on as the engine is turned over by hand which is done by turning the alternator pulley. The voltage should go from 5 volts to 0 volts in a very slow but repeated manner. This would indicate that the ECU is sending the firing signal to the coil. And make sure the coil is bolted firmly to the fender as this is how the igniter finds a ground.
And when checking for spark remove the spark plug wire boot from the leading coil and rest it right up against the coil bore to check for spark as this removes the wire and the plug from being the root cause for the lack of spark.
And when checking for spark remove the spark plug wire boot from the leading coil and rest it right up against the coil bore to check for spark as this removes the wire and the plug from being the root cause for the lack of spark.
Thanks for all your help.
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Jeff20B
1st Generation Specific (1979-1985)
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