To even attempt this you need a multimeter capable of measuring duty cycle.

The one shown in the photos is a Fluke 189. There are less expensive alternatives on the market.

Set-up is fairly simple. You will need 2 alligator clips.

Red clip goes to the positive terminal on battery , the black clip goes to the trigger on the injector.

Removing injector plug

• Using a small screwdriver, pull the white cap off the underside of the injector plug and then carefully slide the upper cover off so as not to bend the wires too much to damage any of the connections.
• Push the 2 wires and their respective terminals onto the injectors.
• Using a piece of electrical tape, insulate the ASD relay pin on the injector so that you don't accidentaly short out the injector.
• Connect you alligator clip and secure it to fuel rail with zip tie (in case you want to prevent it from falling off due to vibration).

Following is out of the Fluke 189 owners manual. Idea is the same for all meters.

When you measure duty cycle, you want to see how much time the injector is spending open. There is a theoretical limit of 85%, where above this number, the flow rate is greatly compromised, and so is injector life.

After making all the necessary connections, you will arrive at a reading similiar to this at idle. It will climb to 50+% as you increase load and RPM. This is especially important on modified engines where the stock injectors are aked to provide much more fuel for the extra air coming into the motor.

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