The truck was repaired at a garage and they replaced number 3 & 4 injectors repaired a broken wire and the ECU was replaced. The truck ran fine for about two days. First days was running fine then on the second day it ran fine for about 50 miles of a 75 mile trip. I checked the wiring between the ECU and the wiring connector at the injector harness. I checked the light green and red I also checked the light green and black and both checked out with good continuity.I also checked the compression and they were within 15 psi if each other. The problem is that 1 & 3 injectors are not working correctly. When I pulled the spark plugs 1 & 3 were dry and 2 & 4 were moist and smelled like gas. I put the harness tester for power on number 1 and started the engine and no light. A nod tester I think that is what it is called. Then I tried letting the truck run for a little bit and the idle smoothed out for a little bit maybe for about 30 sec and the light showed that there was power going to the number 1 cly. I did not do this for the number 3 but the idle smoothed out so it must have been working. When the light came on there was a sound as if a switch had clicked or a rely had clicked it happened every time the idle smoothed out. I went out the next day and the truck does not smooth out at all now. Is it the ECU or is there a relay or something else in the circuit that I need to check? The manuel I have does not show a complete wiring diagram so I am unsure and don't want to replace the ECU if it is not the problem. I am calling a Mazda dealer to see if they can test the ECU without it being in the truck. Your help would be greatly appreciated.
Wednesday, December 12th, 2012 AT 4:09 AM