Originally Posted by Macroblock (Post 310339)

Awesome!

Verifying that the injectors are working is actually straightforward. Remove the Yellow or Gray 22-way Connector to the ECM. Turn the key to ON. One at a time, jump a wire from the (-) Battery Post to positions 1, 2, 3, 7, 8 12, 13 and 18 on the Connector. An injector that makes an audible click, is likely OK.

The injectors used in the early years of the ZR1 are susceptible to damage from ethanol in the fuel (not normally found in premium blends). The injectors develop shorts within their respective solenoid windings. Bad injectors will not produce a healthy click (a totally failed injector will not click). A current measurement can be used to verify the health status of an injector but the simple 'click' test provides discernible results.

Verifying the ECM is sending a (-) signal to each injector, without pulling the plenum, involves opening the ECM and ---CAREFULLY---checking each DRAIN PIN on the 8 Power MOSFETS. Use a 12 volt test light connected to (+) post of the battery. Have a friend turn the engine over (not literally). The test light should blink for each transistor. The ECM PC Board is marked "D" to guide you.

It is also possible to skin some of the jackets on the wires that feed the injectors and utilize a 12v test light, but by doing this you damage the wiring. To repair, coat the bare copper with heated solder and while still hot apply vinyl electrical tape.

In the case at hand, the ECM is unfortunately at fault. It looks like I.C. Component number U13 has failed (Sequential Injection Controller). As a result, only Injector 6 gets a (-) signal from the ECM.

Originally Posted by Macroblock (Post 310649)

The ECM is out of the way of most of the engine heat so, the Arduino should be ok, sandwiched between the ECM's 2 PC boards.

I've used Arduinos on hundreds of devices, many in harsh environments, so I am confident it will be fine.

As I test a few hundred iterations of the code I wrote, I will monitor the Arduino for signs of heat distress.

Originally Posted by XfireZ51 (Post 310615)

Used this procedure today to check injector pulsing. Worked well. It may have helped w a knock issue I have been pursuing for some time, but not sure if this was what solved it for me or not.

Originally Posted by Macroblock (Post 310648)

Verifying that the primary injectors are working is actually straightforward:

Remove the Yellow or Gray 22-way Connector to the ECM. Turn the key to ON. One at a time, jump a wire from the (-) Battery Post to positions 1, 2, 3, 7, 8, 12, 13 and 18 on the Connector. An injector that makes an audible click, is likely OK.

To check the primary and secondary injectors together, remove the Brown 22-way Connector to the ECM. Jump positions 16, 17, 21 and 22 from the connector to GND.

Then remove the Yellow or Gray 22-way Connector to the ECM. Turn the key to ON. One at a time, jump a wire from the (-) Battery Post to positions 1, 2, 3, 7, 8, 12, 13 and 18 on the Connector. Both the primary and secondary injectors that make an audible click together, are likely OK.

To check only the secondaries remove Injector 1 Fuse while doing the above tests.

See page 6E3-A-5 of Factory Service Manual.