Quote:
Originally Posted by Ardent
Another thing you can do is put an LED in parallel with one of the injectors.
If it flashes when cranking, you know that the ECU is getting an rpm signal, and if you don't have spark, it's confined to the ignition system.
If it doesn't flash, you know the problem is not ignition, but crank/cam sensor, ECU or wiring between.
LED: https://www.napaonline.com/en/p/LIT1058A
Pigtail: https://www.napaonline.com/en/p/LIT94902
With a pin probe on each wire, it can slip into the back of an injector wire plug without disconnecting it. |
*the tach operates,indicating around 450-rpm while cranking.
*this suggests that the ECM is receiving the alternating current signals from both Crankshaft and Camshaft sensors.
*with an external power source,the high-tension coil will fire if the C-minus terminal ground is interrupted.
*the wire from the igniter to the C-minus terminal shows continuity and zero impedence.
*I've got to look for the IGT signal from the ECM to the igniter.
*if I find that,it suggests that the new igniter is inoperable,or a bad ground,or open circuit somewhere.
*if I rig up a spark plug cable of identical impedence to the circuit within the distributor cap and join that to a cable and ignition tester/spark plug, directly off the high-tension tower of the coil,and run that to ground;I get nothing while cranking.
*So the igniter is not signalling the coil.
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*while testing all the fuses and relays I discovered that the truck is ' OBD-2'.
*I hooked the ScanGauge up and found one stored code.
* I just printed a set of Toyota OBD-2 codes from
Diagnostic OBD and OBD2 Trouble Codes and the 1300 code I read means 'Igniter Circuit #1'.
*the unit I purchased from Auto Zone may be defective (we can't bench-test them so it's a leap of faith that the thing is going to function).
*same for ECM.
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* I'll swap in another igniter and see if it does anything,as well as interrogate the wiring harness and grounds.
*there's an explanation for why she won't run,I've just got to spend some more time with it.