Post by
dllkbales1 »
https://forums.nicoclub.com/dllkbales1-u137663.html
Sun Jul 05, 2009 6:51 am
When you turn on the key, the fuel pump will automatically cycle to build pressure for the start-up. Pull the injector rail up out of the intake, leaving the injectors firmly in the fuel rail. They may even have clips that lock them into the rail, make sure they are all seated and locked into the rail. Unplug the electrical harness' from each injectoer so they con not be turned on by the computor, all of them. Hold the rail up a few inchs and have someone turn the key on, DO NOT CRANK THE ENGINE JUST TURN THE KEY TO THE ON POSITION. The pump should cycle, and you should build pressure. The injectors should all be closed and nothing should spray, no a drip. Any that do need to be replaced. You can not repair them, the issue is internal and if you were to free them somehow you will have the same problem at a later date. If none spray turn off the key, hook back up all the harness connections. Again hold the rail and turn the key to the ON position. If any cycle now, the computor or the wire harness is turning them on. The harness should have power to all injectors on one wire at each injector plug. Key on and the harness off then injector you should see this with a test light on one of the wires. The second wire is grounded by the computer when the spray in required. Either you have a bad computer and that injector driver is stuck on or the wire that grounds the malfuntioning injector has rubbed thru and grounded itself between the injector and the computor. The current is coming thru the power lead, thru the injector, and finding an improper ground before it gets back to the computer. Now is when you become a real tech. If you see the color of the wires at the bad injector, and see which one has power when unplugged, you will know that the other wire is grounged by the computer to run that injector. If you go find that exact wire at the computer ( use wire schematics to get the correct pin position and recheck the color) you can cut the wire a few inches from the computer, if the injector still sprays, its the harness wire grounding out when the key is on and you have to find the bad spot. If the injector no longer sprays then the computer was turning it on all the time and the internal driver for that injector is the issue. The cut wire MUST be soldierd back together and shrink-wraped. Wire nuts, crimp connectors, and tape are all BS on a computer harness and will fail. The slightest resistance in the wire will effect operation. Its a lot to take in, hope you got it all. Dave