wierd injector probs and other fun stuff - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

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.

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03-04-2013, 03:11 PM	#1
Ztrix Join Date: Mar 2013 Location: Kingston, Tn Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	wierd injector probs and other fun stuff 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.

03-04-2013, 05:42 PM	#2
JustCallMePirate Join Date: Nov 2010 Location: Nor Cal Age: 30 Posts: 18 Trader Rating: (0) Feedback Score: 0 reviews	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?

03-04-2013, 09:37 PM	#3
Ztrix Join Date: Mar 2013 Location: Kingston, Tn Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	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?

03-05-2013, 04:38 PM	#4
Ztrix Join Date: Mar 2013 Location: Kingston, Tn Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	Noob moment. I'm thinking the spark plug wire was intermittently sparking. Lol

03-15-2013, 02:54 PM	#5
p00t Leaky Injector Join Date: Apr 2003 Location: mi, usa Posts: 71 Trader Rating: (0) Feedback Score: 0 reviews	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.