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Macroblock · 07-05-2020

It is possible to test your ECM's ability to activate the injectors with the plenum removed but if the Ignition Module is removed you will not get any injection pulses while cranking the engine over.

Using a noid light allows you to test without actually injecting fuel into the intake port, but unless you have 8 noid lights, you will need to disconnect all the primary injectors and test one feed line with a noid light 1 at a time.

Here's how to simulate the ignition module and fool the ECM so that it sends its (-) signal to the injectors:

Locate your Crankcase Reference High circuit at position "A" on your Ignition Diagnostic Connector. Connect the clip side of a 12v test light to the positive terminal of the battery.

With the key turned to ON, quickly apply and remove the test light probe side to position "A" of the Diagnostic Connector to simulate an on and off input signal. The ECM will respond by activating the fuel pumps and the injectors.

For more info, refer to the Factory Service Manual under Direct Ignition System.

07-05-2020	#2
Macroblock Join Date: May 2020 Location: Windsor Posts: 41	Re: Test injector pulse It is possible to test your ECM's ability to activate the injectors with the plenum removed but if the Ignition Module is removed you will not get any injection pulses while cranking the engine over. Using a noid light allows you to test without actually injecting fuel into the intake port, but unless you have 8 noid lights, you will need to disconnect all the primary injectors and test one feed line with a noid light 1 at a time. Here's how to simulate the ignition module and fool the ECM so that it sends its (-) signal to the injectors: Locate your Crankcase Reference High circuit at position "A" on your Ignition Diagnostic Connector. Connect the clip side of a 12v test light to the positive terminal of the battery. With the key turned to ON, quickly apply and remove the test light probe side to position "A" of the Diagnostic Connector to simulate an on and off input signal. The ECM will respond by activating the fuel pumps and the injectors. For more info, refer to the Factory Service Manual under Direct Ignition System.