ok how the hell can the injectors be shootin fuel in the cylender,but not enough to even wet the plug? the top of the piston dont even get wett.. I cranked it over while watchin the valves open and close,and just as soon as the valves open its done spryin.. If i didnt know any better i would say the cams are out of time,but for god sakes its practicly impossible to screw the cam timeing up on these things. the only 2 trouble codes i have is ects,and air intake temp sensor.. but i tested both of them and they are good. and both have 5v replaced ects for the hell of it,and still nothing. what could possibly be goin on here.. im really lost. it runs great off either,but cant afford to pay someone to spry either in it while im driven.

 

How much fuel pressure do you have? Could be not enough fuel in the intake charge. Don't know if the injector is supposed to spray when the valve is open, or before. Makes sense that it could spray before and then the cylinder draws in the air/fuel mix together?

Try to keep your posts in the same thread so that everyone can follow along with the evolution of the condition and troubleshooting.

 

I also believe that your fuel pressure is too low.
The car is doing what it's supposed to do, sqirt gas.
So no codes will appear to show what the problem is.

If the fuel pressure is too low, the injectors can't squirt much.

You might need a fuel pressure regulator.

 

A quick and dirty test would be to pinch the return hose off and try to start the car.

 

well i'm pretty shure it aint a fuel pressure issue cant garuntee that yet my guage only goes to 30 psi but it jumps right to the 30 without any problem. ill probably get one and let ya'll know for shure.. I tried to pinch the return line to force all fuel to injectors,but didnt help. mabey a tad but not much plugs are still dry and top of pistons are dry.. the injectors are all new so clogged injectors are out of the ?. Im kinda wondern about if the fuel goes in with the valves open or closed. with the plenium off i watched it and it sprays strong till the valves open soon as they open,it stops sprayin. just acts like the damm cams are off,but i mean all the marks was right on the money,its kinda hard to screw the timeing up on these things with the color links and the dots on cams it was all lighned up. thank god for beer. definately a interesting job. only other thing i can come up with is why wont the ects and air temp sensor codes clear when they both tested good. and i done replaced the ects for the hell of it,and no difference. i unhooked the battery over night,unhooked the ecm harness,and put the negitive and positive cable together. and still comes up both codes. i dont even have to try to start it just turn key on,turn the diagnostic thing on the ecm and it comes up.

 

Fuel injector timing is controlled by the camshaft position sensor signal. If the sensor is working then the injector timing has to be correct. If that sensor fails, it will default to the crank position signal. With that said, it's pretty much impossible for the FI timing to be off.
Even a slight mist of fuel, which is really all that you should see, will eventually wet the plugs and cylinder down if ignition isn't happening.

Check the injector signal with a meter, I believe they fire on the grounding signal through the ECM ( somebody correct me if I'm wrong). Check all the engine control fuses too.

How can you see the valve open and the injector spray??? With the engine together, there's no way to actually see these events...

 

yea thats whats very confusein.. no matter how much it sprays sooner or later its gonna wett the plugs. i took the upper intake off and watched it through the intake runners. far as pulse to the injectors u are right it does get its pulse from the ecm wich is a ground pulse.. thats another issue i dont quite understand wich i put a post about weak injector pulse. if i disconnect the injector wire,and put a contuity tester it light bright indicatin good ground signal,when i hook it up to injector its not so bright. but like i say they are mistin. now if i turn the key on and the piston all the way down wich the intake valves are open and ground it with a jumper it sprays great and goes into cylender like its supposed to. so i figured well ill just run it a bit off of throttle body cleaner and ran it for like 20 min like that and only code i got was a 55 wich is a no fault code. just dont get it its like the injector timeing is off,and like u say the camshaft positon sensor controlls that,but if it was bad why woldnt it throw a code? this is defnately a intersteting malfunction.

 

I would Ohm test the injectors using a multi-meter. Do have a multi-meter?

Here's a video a guy posted to youtube for Nissan V6 injector testing using a Quest as the example with Nissan Phase II injectors. It is the same testing routine for Maxima injector testing since both cars use Nissan Phase II style injectors.

Have you checked out the testing procedure in the Field Service Manual? I have a link in my signature line to a place where the FSM can be downloaded.

Also note, if you are worried about injector spray, you might save yourself some time by just sending the injectors out for a refresh (new O-rings and screens) and true injector spray pattern testing.

How long has it been since the fuel filter has been changed?

The Fuel Filter and Fuel Pressure Regulator (FPR) are maintenance items. To avoid unplanned low fuel pressure problems, I usually replace the FPR somewhere between 150,000 and 175,000 miles. That is if the FPR actually made it to 150,000 miles. On my first 95 Maxima, it lasted about 135,000. From the earlier post, it looks like the FP and FPR are ok -- so let's move on to the injectors.

Injector Test


Injector Spray Testing Video

 

well its possible the pressure regulator is bad,did seem the piston was a little wett when i pinched the return line off. its not bad or clogged injectors or the fuel filter because i can turn the key on and ground the injector on the cylender thats on intake stroke intake valves open and it sprays great,. so that would rule out dirty or leaky injectors. and the fuel filter bein restricted. its really strange.. recon a good? would be is does the fuel shoot in when the valves are open,or is it before they open and it fills the intake runners full of fuel,then dumps it in at once. its a multi port injection fuel system.

 

Assume nothing.

You tried it your way, now try it our way.

You mentioned that some injectors work fine, others dont.

Have you watched the videos which CS_AR posted for your benefit.?

 

yea i did watch the vidio. i done all that and it tested fine. far as metioning some injecors firen and some not,that was a leaky injector it was loossin all the pressure. i done replaced it. the injectors are all new.

 

Ok. Good. Now how about the pressure regulator?

 

Which brand of injectors did you choose. Many of our members have mentioned that some brands of injectors work better than others.

 

thier oem hitaci injectors,and i completly pinched off the fuel return line so that eliminates the pressure regulator. my problem is the injectors stop sparyin soon as the valves open,its not that they aint spryin a good pattern or anything like that they should shooot fuel in with valves open,not stop sprayin when valves start to open.

 

Finaly got the ol girl runnin. my original problem was it had 3 bad injectors,so i replaced all 3 new,well one was bad and of course it was in the back, so had to remove the plenium once again,and when i did i didnt hook up the egr vaccume tube. had no clue it was a vaccume most egr vaccumes are hoses not tubes,but shure enough it was loosen all its vaccume there,and not enough to pull fuel into cylenders. go figure. shure aint easy hookin that thing up and gettin the gasket in with it. but shes up and runnin, got a miss but im prety shure thats just a plug. thank yall for youre help and inputs.

 

Glad that you got it running. So a brand new Hitachi injector failed
under the uim. That's rotten luck. It would take a while to figure out what the problem was.