# car problems



## 92vg30ohc (Mar 5, 2013)

well lately my car had been randomnly misfirng and if i would shake on the the injector plugs it would help smooth it out the car would miss on different cylinders randomnly i was guessing cause the injector plugs was loosing connection but the car would never throw a check engine light so i figured it was but plugs on the harness so i went to the junk yard and pulled a whole fuel rail and cut the wire harness to each injector and rewired the clips to my car and installed the fuel rail started my car up and i have a dead miss on number 5 now that wont go away no matter what i do put the noid light on no 5 injector have good pulse have good spark from the wire and have good compression on no 5 cylinder and can here the injector ticking with steth have no idea why cylinder no 5 is at a dead miss another funny thing is am not getting a check engine light for the problem i had a code 11 stored in my car so i replaced the whole distributor instead of the crank sensor cause i had a spare still missing on no 5 good spark good injector pulse and can her injector working with steth but no 5 is not hitting and again dont understand why i dont have a check engine light any suggestions would be greatly appreciated all other cylinders are doing good:wtf:


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## smj999smj (Jan 1, 2006)

Maybe the fuel injector is clogged at the nozzle? Bring it down to the basics: you have spark, the injector is getting power and the ECM is pulsing the ground to "fire" it, you have tested compresson. Only thing left would be a fouled spark plug, intake gasket leak @ the #5 intake runner, or a bad fuel injector. Confirm the spark plug is okay, spray some carb cleaner around the #5 intake runner while running to check for a possible leak (which I don't ever recall seeing on a J30 Maxima...and I've worked on a lot of them!) and if that's all good, I'd replace the #5 fuel injector.


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## 92vg30ohc (Mar 5, 2013)

If I supply a ground to the injector by running a jump wire from the injector wire n tapping on the ground post of the battery I can make the injector work n i put all new plugs in when I did the job it makes me think its more ECM related like the injector is throwing the fuel in at the wrong time like when the pistons going down instead of coming up another reason I think it's computer related is I don't get a check engine light from it I would think it would throw a #5 misfire code


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## 92vg30ohc (Mar 5, 2013)

I'm lost really but the cylinder is getting fire when I pull the #5 plug its wet n smells like gas I got injector pulse n good compression but still have a dead miss on the cylinder it's got to be throwing the fuel at the wrong time is all I can think cause if I manually do it by running a jump wire from the injector harness n ground it by tapping on the ground batt post I can make the car hit on #5 any more advice would be appreciated thanks


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## smj999smj (Jan 1, 2006)

The diagnostic system is not that sophisticated to be able to identify a particular cylinder's misfire. That type of capability didn't come around until years later. The self-diagnostic system in the J30's is fairly crude by today's standards. Only thing I can suggest is to find someone or a shop that has an oscilloscope to observe and compare the wave patterns of the ignition system (specifically #5 compared to the others). You could perform a cylinder leakdown test just to make sure you don't have a burnt valve. As far as the injector, just because it's wet doesn't necessarily mean it's spraying fuel. You could install a fuel gauge and observe the pressure drop as you manually "fire" each injector.


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## 92vg30ohc (Mar 5, 2013)

I can manually make the cylinder fire by running the lead from injector harness in tapping on the ground terminal on the battery so I know its not a burnt valve jus dont know why the cylinder is firing have all the necessary things to make it fire but it jus wont maybe the computer is sending the wrong signal to the injector an it's throwing fuel at the wrong time like a bad ground in the ECM or something


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## smj999smj (Jan 1, 2006)

The ECM doesn't send any signal to the injector. Battery power is supplied to the injector. The "driver" inside of the ECM makes the "pulsed" ground connection for the injector. It's rare but very possible you have a bad ECM.


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## pockittin (Jan 6, 2012)

92vg30ohc said:


> I can manually make the cylinder fire by running the lead from injector harness in tapping on the ground terminal on the battery so I know its not a burnt valve jus dont know why the cylinder is firing have all the necessary things to make it fire but it jus wont maybe the computer is sending the wrong signal to the injector an it's throwing fuel at the wrong time like a bad ground in the ECM or something


Could it be that you wired the injector with the wrong polarity? For example red to green and green to red. I just picked two colors as I don't know what colors you have.


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## CMax03 (Jan 17, 2009)

Hope he found the problem....We'll never know will we?


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