Lets say we are doing a V6 engine like the one in this GMC 4.3 Jimmy. The truck is running off the stock OEM ECM; which is firing one coil and 6 injectors. We can use the PRS 2, 4, or 8 to run this truck. In this case we will show you how the PRS 2 will do the job.

Our plan is to configure the PRS 2 to fire one coil. For fuel, we will pair two injectors, as per firing order, to 1 of 3 injector drivers.

The first step is to take the fling leads from the PRS 2 and just tee them to the stock harness. We used www.Alldata.com to get the trucks OEM ECM pin out. We looked at the PRS wiring diagram and marked the wires we will need to tee into on the GMC wire harness. We then teed in all the input wires we can, but did not cut any.

Now we can start and run the truck, still running on the stock ECM, and monitor the PRS on our PC or laptop. We now set up the global setting as per the manual instructions. A good study of the manual before hand is recommended.

Now that the RPM reading is accurate and the live data is being displayed we can now go on to wiring the coil. What I like to do is wire in a 2nd coil with a wire and spark plug hanging out of it, temporarily. Now I can still run the truck, which is still running on the OEM ECM, and compare the timing from #1 plug to the signal I am getting from the PRS coil. If all looks good just swap over the coil wire and we are now running on the PRS for timing. If your signals are not adding up you may have not configured the PRS correctly, so you will have to go back to the global settings and see what you may have missed.

Ok, now we have control of the timing, and we will do the fuel next. We refer to the Alldata print again. We find, in this case, 6 injectors wires. Because the PRS2 has 3 injector drivers, we pair them up according to firing order. (If we use the PRS4 we could have one driver for each injector.) The first pair we cut and wire to our first injector driver. We start the engine, 2 injectors are being controlled by the PRS and the other 4 are being controlled by the OEM ECM. Tune the 2 injectors with the PRS analog map until the engine sounds normal again. This is going to give you a good idea what the fuel #'s need to look like. Now swap 2 more injectors over, 2 at a time. Now your car is running on the PRS, and you can take it from there.

We will not be removing the OEM ECM on this vehicle because we need it to control the transmission, but if it were not, then it could be removed. As long as we are leaving it, we let it continue running the Idle air motor.