#1 Cylinder Misfire

[I Need $$$]

I have a 1992 240sx. I know cylinder 1 is misfiring because when i pull the harness off of injector 1 RPMs do not drop. It started running rough last week. When I was diagnosing this problem I found that injector 1 was open while the rest read 11.3 ohms. I replaced the injector and the car ran better for 3 miles then same situation only all the injectors had 11.3 ohms resistance.

Since then I have done a dry compression test and found an average of 150 psi with a difference of 3 psi between the lowest and highest. I have good spark from all plugs. I have also backprobed the injector and found the scope pattern of injector 1 to match the rest. Also all EGR ports are clean.

I have been told that it could be the ECM. I just wanted to check with more resources before I go dumping money in sensos and an ECM. I appreciate everyones help in advanced.

Travis

[NISTECH]

If you back probed the injector with a scope [not a volt meter] and you have a good pattern your ECM is not the problem. What did you have your scope set on? What was you V per division and what was you ms per division? While watching the pattern at the end of the fire when it drops back down does it go all the way to the 0v line or does it come down about 3/4 of the way then gradually drop to the 0V line?

[I Need $$$]

I did use a scope on the injector. I will retest it tommorrow and write down all of the information.