cylinder #3 .... Not working!!!! completely lost please help

[WickedRACEr]

Hi I have a 93 240sx se hb ka24de and I found that my #3 injector wasnt working and replaced it now I still am not getting anything from that cylinder I have strong spark and compression. What do I do next to check wiring to see if the injector is getting signal or what next?

[WickedRACEr]

no one? I got most of the fire triangle here I got spark compression and had a bad injector but now idk why its not firing any direction?

[WickedRACEr]

sriously no love?
I know that the injector is getting constant voltage from the red whire after the connector and the signal ground wire is good all the way back to the ecu. So does this leave me at thinking the ecuhas a bad ground for that clyinder? is there a way I can check this with out swapping ecus cuz my only resource for that is wait for one for ebay? still looking for some help any one? thanks

[240man91]

so u have fire an compression an injector is working you say? but still not firing. i do not see how that can b trure how do u know its not working any codes hows it run

[WickedRACEr]

Runs like a ka with only 3 cylinders working,... it bucks all over the place responds slower than cold malasses and no power. No engine codes come up on the obd1 reader I used. I know its not working because it runs and I can unplug the injector, spark plug wire, or use the cylinder load test on cylinder #3 and theres no differance in the crappy running and if I do it to any of the other cylinders it dies. I did a compression check because I was almost sure the whole cylinder was smoked but it held compression fine, and using the data reader it told me the injectors were supposed to have between .10-.15 ohms resistance and all did but #3 was way out of bounds so I replaced it and that didnt solve the problem hence the wiring check. and I know the sparks there cuz it arks to a ground and the spark check tool lights up. I don't know if the injector is spraying or getting the ground signal to do so, I don't have a injector noid thing and I didnt feel like pulling the fuel rail and making it spray cuz Im pretty sure it wont. I just dont see any reason left for it not to be gettting the firing signal unless its not getting the ground signal from the ecu, because correct me if I'm wrong the red wire to the injectors is a constant 12 volt and the other gives a blocked ground signal to get to injector to fire? thats my understanding of it any ways. thanks for any help though I'm trying to keep my cool this is getting fairly frustrating cuz I just wana drive my 240 around on all 4 cylinders this summer!

[240man91]

ok i see now u are ging to need to look for a short

[WickedRACEr]

By cutting apart the wiring harness and following it back through the firewall to the ecu? and just a visiual check cuz its going to be a pain in the arse to hack into the taped up harness and look. I think in the mean time I may try a differant ecu.... Thanks again for any direction or suggestions I'm bound to get closer to the problem.

[240man91]

well i would try to get a tester an test it every foot or so till u get power or start at ecu an if theres no power then it could b ecu but if there is the go about ever foot an test it an when u lose power then u know where the wire problem is thats what i would try so u dont have to take it al apart but yea that sux man there is a bunch of wires in there can u get another harness?

[WickedRACEr]

I tested with a circuit probe light and it flashes like it should where the injector should fire the injector tests ok it held over 135 psi cold and as far as I can check it's getting strong spark. I'm completely lost I have no idea what left to do!

[240man91]

bad rings what did the compression test say

[WickedRACEr]

it held 135 psi cold like I said and I only cranked it over a few times and the needle didnt drop at all!

[240man91]

that is kinda low i get 180 in all. what the other ones say