I have limited my fuel injector problem to the #4 injector by: pulling each spark plug wire one-by-one. When I pulled all the other wires the rpm went down, and car idled even rougher than it does now. However when I pulled the #4 plug wire, there was no difference. I could also tell that there was electric going thorough that wire because I heard/seen the spark when I touched the wire to the manifold. right way of checking????

So probably tomorrow I'm gonna try and change that injector. Now is where the main questions are. I read the directions at: http://www.4dsc.com/articles/drivetr...lacement.shtml
for changing injectors, and the way that guy did it, seems much easier than the way the haynes manual says to do it. A few contradictions:
--the haynes says to drain the coolant.... i dont know why
--the haynes says to take off the fuel lines completely off the car, and then "cut through the hose" to remove an injector, while they guy at 4DSC.com just removed them straight from the car, by twisting and pulling
--the haynes says to lubricate with gasoline while the guy that did it on 4DSC.com lubricated with motor oil

other than those things it seems kinda the same. kinda straight forward at 4DSC.com.... another thing, do I have to change the intake manifold gaskets?? and no sealant there right?? just slap on dry gasket, or can I use a little black RTV?
Whats the "black dot" & "blue-dot" stuff?? 2 different types of injectors for the VG???
thanks in advance all...all help/tips appreciated. this is the 1st time doing this on a max, and without any help..

 

Well, I've done this like 5 times recently, so I guess that qualifies me as an "expert". I can tell you how I did it, and you can use your own judgement.

The way you checked it is correct, IMO. Sounds like #4 injector is bad.

On the VG, you have to remove the upper intake plenum in order to get to the injectors. There's 2 pieces to it. You don't HAVE to change the gaskets on anything as long as they are in good shape with no tears. I didn't use any RTV except for one spot that I accidentally damaged.

To pull the injectors, I have done it both ways- removing the whole fuel rail, and just removing one injector with the rail still attached to the car. In your case, I would not remove the whole rail. Basically, I used a pair of channel lock pliers on the rectangular connector and a combination of twisting and pulling. I used motor oil to lube the o-rings, on advice of another .org member. Make sure you use new o-rings. 2 per injector.

You don't need to drain the coolant. There are a couple of hoses on the back of the intake plenum that have coolant running through them, and they need to be unhooked to remove the plenum, but you won't lose much fluid.

I used the 4DSC.com instructions the first time I did it. I had no problems whatsoever.

The blue-dot / black-dot thing is supposed to mean something, but I don't know what. Maybe flow rate, maybe just Nissan trying to be difficult. Mine had black dots in it originally, and I have used black dots as replacements. I don't think it makes a huge difference tho.. (may get contradictions on this)

 

make sure you depresurize your fuel system before you do this job. take out the fuse for the fuel pump and turn the car on. let it die and crank it a few times. i think? i did my injectors once and it wasnt too bad. the first time is a pain in the *** and you want to beat your car with a wrench like me. actually the reason why it was bad because it was below zero and my garage heater didnt work as well as i thought.

right now i have a leaky injector i think in #2 IIRC. anybody know how to check the other injectors while i have them out. i konw somthing about them being between 10-14ohms. since i will have the manifold off, how do i clean them? what is the correct method? help me and aminus out. thanka

joshua

 

If you ohm out the bad one, and it is within spec, then it's possible you have a leak. It's hard to tell without the engine running and seeing it actually leak, though.

 

i commend you on dooing your research before asking. i dont have the answer to your questions, , sorry, just dooing some research myself. on my car it seems like #5 cylinder needs an injector, pulled the wires and #5 has no change, pulled the plug and the electrode is all white, checked the hayes manual and it says either it's too hot(Insufficient cooling) or a lean mixture(which would also cause it to run hot) , gonna pull a couple more and test the resistance ont he injectors

 

well i attempted this today, and it was pretty straight forward. Basically all I did was take off ALL the hoses and wires connected to the upper intake manifold and took it off (easier said than done, especially when those hoses are 15 years old), I ended up ripping 2 hoses the EGR one, and another thick one on the front.... The 4DSC.com way is definately the way to go, the haynes makes it look much more dificult than it is..
I did encounter one problem though. When I was taking off the bolts for the lower intake manifold, one of them slipped out of my hand and went into the "curvy" manifold.... I tried sticking my fingers in, but the manifold curved and I couldnt feel the bolt at all... The only thing I can think of is to get some kind of long flexible magnet thingy and stick it down there, OR take off the manifold (is that hard)???

 

magnet on a string should help..

btw, what IS up with all these injectors going out??

 

VG injectors tend to go out. On our 90 GXE they went out around 50k.

 

Mine isn't a VG...neither are most of the others I've seen except 1 or two..

 

How can you tell if you have Blue or Black dot injectors.

 

look at the connector on the injector.

 

well I took off the maniflod (or whatever you call it) under the lower intake manifold. It was pretty easy, other than the fact that a bunch of coolant poured our. The bolt was sitting right there, so I just pulled it out with my fingers..It was impossible to do it with a magnet, because it got stuck in the curve..So now for the gasket that was under the manifold that I just removed, theres 2 and they are metal, so I should use some silicone on them right???
..i hope I dont mix up the bolts/hex screws/washers....
for the injectors, there is a blue or black dot on the side facing the engine.. mine has a blue dot