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View Full Version : wierd injector probs and other fun stuff


Ztrix
03-04-2013, 03:11 PM
i have a 93 240sx i picked up recently. i did an upper gasket set and removed emissions ect. anyways, i had some issues with my injector orings for awhile. Got that fixed for the most part. now while idiling my #1 cyclinder isn't firing. has spark. now for the wierd part, i unplug the injector and it seems to start hitting. manifold temp on the 1st cyclinder goes from 175ish to 300+. i replaced the injector and it was hitting perfectly. now i go to start it today and its missing again, same prob. any ideas? ive never seen anything like this lol.
im only getting one code,34- knock sensor... when i was pulling the intake mani and looked at the knock sensor it only had one black wire going to it. just curious if theres supposed to be another wire or not.
im having Alot of fun diagnosing this one so if anyone has any opinions or ideas, im open to anything here lol.

JustCallMePirate
03-04-2013, 05:42 PM
Well your knock sensor wont have anything to do with your cylinder not firing, ill try and check the wire thing when I get home for you if no one has answered yet. Have you done a full tune up on it yet? Plugs wires cap rotor?

Ztrix
03-04-2013, 09:37 PM
Agreed. And I have. New cap and rotor. New plugs my wires are good. All have emitted spark. I read a thread on tricking the ecu into thinking it has a knock sensor earlier. Thoughts? The wiring is hella f***** up. Ive went through my harness and found no broken or messed up wires other than that.
Heres what's odd. When its idling and missing I unplug #1 injector and it starts firing. Ill check the manifold temp on that cyclinder to see if its close to the same and it is. Then ill pull the #1plug wire with the injector still unplugged and it starts missing. Seems to me that for some reason the injector is spraying at idle without getting signal from the ecu. Ive pulled the rail and none of the injectors are leaking under pressure. Wierd right?

Ztrix
03-05-2013, 04:38 PM
Noob moment. I'm thinking the spark plug wire was intermittently sparking. Lol

p00t
03-15-2013, 02:54 PM
Could be the injector connector, see if the contacts look shitty. The rubber boots on them are all cracked up usually. You can also move the engine harness around with it idling and see if you can get it to start missing.