So i know the symptoms for a bad injector are a rougher engine under 1500 rpm that then smoothers out after 1500 rpm. My engine has this trait and sometimes and idle theres a misfire, altho i clean the CTS and that one wire that goes to the distributor cap area dont know wat its for and that seemed to get rid of the misfire but its still rough up to 1500 rpm. But why would my idle be smooth ish with the occasional misfire but then always be rough til 1500 rpm, wouldnt a bad injector always misfire? I have spare injectors (5) so il replace the bad one but i couldnt find a bad one. I pulled each cylinder plug while it was running and all made the idle worse as if they were all fine. but when the car is running and u look under the hood u can see the engine miss every once and a while. So why would it miss once and a while but ALWAYS be rough when accelerating under 1500 rpm? How can i find my bad injector?

 

Bump.. I've got problems with my injectors too, I think.

 

bump... any suggestions?

 

i had a bad injector on my #3 cylinder....the way we found it is take out the plug and get someone to start your car for 3 seconds and look into the cylnder with a flashlight.....if you see the gas spray, or smell it...your good....my #3 had a bunged injector and no gas was going to the cylinder....new injector, maxipad runs sexy now...try that to find your bunged injector

 

I went to a mechanic and asked him what ingectors went bed. He told me three and five. I replaced em.

 

good advice there dude...that will help him out all kinds.


If all you can contribute is to recommend taking the car to a mechanic,then stop posting,this forum is not about that..

 

true that mygreenmax, but anyway, driftking posts a good idea but i think all my injectors would spray, but maybe one would spray unevenly or not in the correct pattern? Since its an intermittent misfire, and i know im not running on 5 cyl's (unlike my other max) thats what makes this so hard to find the bad injector. Altho if i tried cranking it with the plugs out and one injector sprayed inconsistently i would assume thats the cause of the roughness/stumbling?

 

Have you checked your plug wires and distributor cap/rotor lately? These can cause weird problems.

 

Injectors?............What wire going where exactly?............ photo?This can simply be due to the age of the motor and its current state of wear influencing blowby etc etc ................... decent quality video showing your issue while the motor is idling will certainly help .................... as would a video of you actually "So why would it miss once and a while but ALWAYS be rough when accelerating under 1500 rpm"

What is the exact WOT pressure values for each of the individual cylinders? (compression test)IMO that is a guaranteed way of getting fuel in your eyes and going blind

 

I'm not just going to settle for "its normal wear and tear" maybe its normal for our cars, but our injectors are made of ikea grade plastic.

When I rode in maxmaxima91's car, it was super smooth. My VG sounds semi rough and unrefined, and misses at idle, while his sounds super smooth and never misses at all.

Of course he has brand new (relatively speaking) 350z top feed injectors, vs our 5-15yr old injectors. But my point is with good injectors there should be no poping or anything like that. I'm considering getting the 2nd gen setup just to get top feed injectors.

~Alex

 

I don't think its "normal" for our cars at all ................... its just reality - eg - I have a super smooth VG with 270000km running on stock original injectors ................ all I know is I can bet my house on the fact that MY motor is not performing as it did when new - I may just be lucky that the wear is pretty even in all the cylinders and its influence on the motor is pretty evenly distributed between the individual cylinders whereas any other given motor may have a particularly bad cylinder/valve/seat/ring/ etc etc etc influencing a particular cylinder more than all the others on that particular motor.

Simply chucking huge wads of fuel into a worn cylinder to guarantee reliable ignition is not necessarily the correct answer ..................... time/age in itself is not the cause of injector hassles.

 

When I bought my car at 65K miles, it ran like you described. Idle was rough, but since it ran fine otherwise, I ignored it. It actually ran until 146K miles like that, then one day, the car ran really rough and it struggled to accelerate.

I used a multimeter to check the resistance of the injectors and 2 of them were out of spec (should be like 10-14 ohms, if I remember correctly).

So I bought 2 new injectors from Nissan and the car idled like brand new after I installed them. The car is at 189K miles now and it still idles smooth and runs good.

 

Alright maybe il try the voltmeter check. How do i perform this? I really have no idea so if someone could explain it that would help, thanks.

 

You have to take the plugs off the injectors and measure them directly. On the back ones its easy, and on the front ones you have to get to the electrical connector mounted to the drivers side of the block. Its a bigger 6 pin connector.

~Alex

 

I had to change out my #3 and 5 because of rough idle. They ohmed out at 19 and 56, way to high. I changed them and voila, good idle and AWESOME driveability!!

BTW I got them for $85 a piece, yellow dot or green dot!!

 

how about you take a stethoscope and listen to each injector at a time and listen for the one that isnt clicking at the same rate as others if you thinking it could be that an injector isnt firing right or is clogged and clicking at a slower speed there for injector is not working properly.

 

I did that when i bought the car and a couple tiems after, but you can hear all clicking away. And no matter which spark plug u remove theengine gets worse signifying all arefiring.