Newbie here. I'm down to 12 posts before I really tie up some server space

Ive read dozens if not hundreds of threads on fuel injectors and dont think I have the answer yet. Here goes.

My buddy gave ma a 94 max FREE after he began having issues with poor running. I save the Nissan dealer crap. 6 new injectors and it still ran like crap so he gives it to me. I trying to fix to give to my niece for her 16th birthday. I wasnt there to confirm the proper installation of the injectors but he said they lubed them and such.

Whne the key is turned on the fuel system pumps to 43 psi and then at least 2 of the injectors open completely and the pressure drops to 0. I dont recall which ones.

I've checked the resistance and all are the same but not 11-14 as some threads have stated. they are 6 or so.

Any ideas?

thanks very much

 

sorry to highjack

 

were they "brand new, never ever used, came from a factory that makes new injectors" new,

or

were they "brand spankin' rebuilt" new?

I am leaning toward the second, since they ohm at 6....

our cars dont take rebuilts, well. they die.

 

if it's an a/t (for sure on the VG-powerd GXE model, and maybe-but-i'm-not-100%-sure on the VE-powered SE model of that year) you may have a swapped front injector harness, swapped for the a/t inhibitor controller.... this will cause weird crap to happen with the front injectors.

however this 6ohm resistance is concerning, to say the least.

 

I spoke with the previous owner and he said BRAND new. I dont know if the store sold brand new/rebuilt. you know how the auto parts stores are.

Aside from the ohm check and pulling the injctor to check for bad/pinched/faulty orings, is there any other way to check them.



thanks

lewis

 

nope, have to do it the right way or you won't necessarily get a correct answer

 

Ok, so I tried another ohm meter and all 6 injectors hve about 12.5 ohms. I then pulled all injectors. #1 cylinder had lots of fuel in it. I couldnt tell on the other five.
The bottom oring on that injector may have had a small tear in it but it could have happened while twisting to remove them as they fly out at the last minute. I also found #4 to have a large tear but not sure if I did it.

The injectors are made in Japan but not sure if they are new or rebuilt new.The guy that gave me the car says they were new.

Any ideas?

thanks to all for the help

 

try new o'rings

 

Just to refresh. When I turn the key on the fuel pressure goes to 43 psi then some injectors open wide and disperse all the fuel into the cylinder.

I will try new o rings. Anything else I should take a look at?

thanks again

 

have you checked the voltage on the harness-side to see if maybe one of the injectors' signal wires is shorted back to ground or something, causing it to be open all the time, perhaps? Kentucky Fried Wire can cause some weird crap to happen.

 

I assume 12 volts for those wires?

 

yes.... sort of.

i don't remember precisely.... i know that the circuit has a shared +12v and the individual wires (going back to ECU, not from the ECU, as is commonly misperceived) get grounded by the ECU to complete the circuit.... what I don't know is the state of the wire when the injector is off. On my friend's probe, the control wire pushes 12v against the main shared wire (also 12v), and that cancels out and creates 0v and the injector closes. It grounds to open the injector. Maybe the Maxima ECU is dual-hot like that, or maybe the control wire is no-connection until it grounds.... sorry to not be more help but i've never played with that before. Anyhow, if you hook a multimeter to both tips, you'd see 0vdc when off, and as you have more fuel pumping, the signal would go up and up (perhaps 2.2vdc when holding 3000rpm, etc... just pulled those numbers out my *** btw). If one of them is showing 12vdc across the pins at all times then that means the injector, while functional, is being TOLD to stay open.

 

Ok, I finally did the injector seals. Car strted right up but smokes and it smells like running rich? Spark plug wire in wrong spot?

also runs rough. when I put it in gear it back fires 9popping sound in exhaust). Plug wires maybe?

thanks to all

lewis

 

It sounds like it is still missing (thus not running on all six cylinders). Why don't you try pulling the spark plug wires at the plug one by one (and one at a time). The engine should run worse when you pull the spark plug wire, then better once it's reinstalled. If it doesn't run worse, just runs the same, that particular cylinder is not firing because of either a bad fuel injector, bad/rotted electrical harness, or an ignition (spark plug/spark plug wire, etc.) issue. I did this and was immediately able to determine which injector (in my case) was causing the problem.

 

Another easy way to test injectors - apply battery voltage directly to its contacts for a 1/10 fraction of a second and you should hear 'click'. If you don't - it doesn't work regardless of its resistance. Engine should not be running of course and injector should be disconnected from the harness. For rear ones you can apply the voltage to the contacts of disconnected socket. Just don't shorten the battery in the process.

I'd check spark plugs as well.

 

That's pretty cool. I'm learning a lot here

 

It turned out to be 2 plug wires crossed. runs like a champ. thanks to all for the help