Has anyone replaced injector #4 w/o removing plenum?

[carcrazyguy]

Just as the title say. I began to try this, got a couple of the rail bolts off, but decided to ask if it is even possible or worth it b/4 I go any further.

[Q451990]

I think I did #3 once without completely removing it, but I had to take a good bit of stuff loose to get to that point. It's much safer to remove the entire rail and do the replacement at a work bench... then pressurize the rail and check it before putting everything back together. There have been waaaaay too many stories of hydrolocked Qs lately.

Heath

[carcrazyguy]

I had planned to pull the rail off regardless...I just wondered about getting it off to replace #4 without pulling the plenum. For that matter, how big of a job is remving the plenum anyone?

[maxnix]

Probably time to perform the under plenum and Valve Cover maintenance anyway. Several great posts in IOM.

[carcrazyguy]

I totally agree, but this is my dad's car, and I can only do so much work on short visits.

For that matter, I am in trying to convince him to get something else, as a Q45 is a great car for a meticulous, mechanically minded owner, but not for a retiree that simply wants a turn-key car. In other words, due to the car's age now, it really doesn't make sense as it once did for him when it was new. But he still loves it, but doesn't realize it isn't like his previous cars (Maxima, Camry, etc) where you can just drive indefinately with no preventive maintainance and fix something (simple) when it breaks (as he has more less done with it so far). But now sheer age (and Murphy's law) makes this method Russian Roulette.

In addition, the nearest Infin dealer is a 130 mile round trip, and I wouldn't even trust any local mechanics to change the air filter. I have fixed most things up until now, but any major job...I don't have the time and place to fix. And I wouldn't want him to dump $2000 into it (what the dealer would likely charge to change the gasket and injector).

So bottom line, I simply need to get the injector replaced and then go from there...and (currently) only one injector is dead (and the rest are in spec), so what would be the simplest route here...And if I do have to pull the plenum, how long is that job (and is there a specific writeup for it)? I found some that indirectly dealt with it...

[maxnix]

I agree with your analysis, although I am sure he will sorely miss it.

Or you could switch it out and take it home and restore it so he can drive it 100K longer? Do you have any other dads running around? They're pretty special.

[carcrazyguy]

I agree with your analysis, although I am sure he will sorely miss it.

Or you could switch it out and take it home and restore it so he can drive it 100K longer? Do you have any other dads running around? They're pretty special.

So far, other than the regular stuff (brakes, belts, etc) I have also done the water pump, AFM, fuel pump recently - as it all seems to be going pretty close together. So the catch is that the car is at the age (and mileage) where stuff will need to be done and things will happen. One injector is dead and another is at 17 ohms...and since they are all the same age, it is likely that more will follow.

Also, if he breaks down somewhere, he will end up at the mercy of whoever tows it to their shop. A couple years ago in FL he got taken to the tune of $986, and from all I could tell from the "work" they did, the harness for the AFM had come loose.

It's just not the right car for him anymore. So my plan is to convince him to get something new w. warranty in the next year or so...or at least something more suited to his vehicle service ability (turn key and pump gas). The car would be perfect for a mechanic or DIY person, but not for him.

As far as I am concerned, I already have a slew of similar cars and am about to buy a J30 on top of that...so I need that car like a hole in the head.

[goody90q45]

......So bottom line, I simply need to get the injector replaced and then go from there...and (currently) only one injector is dead (and the rest are in spec), so what would be the simplest route here...

The simplest route it to not remove the plenum but just unbolt enough so you can move it off to the side to get to #4. This will involve removing the TB, PCV, and EGR valve and unbolting (but not removing) the IAC valve. Removing the IAC is a pain because of the 2 hoses attached to it. Once you get these 4 components out of the way and remove the 16 bolts holding the plenum you will be able to move it a couple of inches. From there loosen a couple more hoses underneath and you'll be able to move the plenum enough to easily reach #4 FI.

I haven't listed a step-by-step for removing the plenum and have only covered the major components attached to it. You can search here on NICO or go the Tech Help section at Q45.org for specifics. You definately want to do some reading so you understand the steps before starting but once you're done you'll see that it's not that complicated if you are organized about it.

And if I do have to pull the plenum, how long is that job (and is there a specific writeup for it)? I found some that indirectly dealt with it...

Depending on who you talk to it might take 2 to 11 hours to remove the plenum, replace an injector and put it all together. I spent 6 hours a couple of months ago with many breaks and diversions for the same job. Q45.org has a good writeup but typing PLENUM REMOVAL as a keyword searching in the Infiniti Online Mechanic forum will give you all the info you'll need.

[carcrazyguy]

Thanks...that is what I needed to know more less. I guess I will have a talk with him about his options.

[maxnix]

I understand your concerns, but a restored G50 is an ultimately reliable car. Even more so than some domestics and most Europeans.

[carcrazyguy]

That may be true, but lets face it, a mechanical restoration is not going to happen in this case. Best case scenario, I will fix the injector, then he will likely just keep on driving it until the next problem.

[maxnix]

That may be true, but lets face it, a mechanical restoration is not going to happen in this case. Best case scenario, I will fix the injector, then he will likely just keep on driving it until the next problem.

Too bad. The 1995 G50 was judged the best made car after 5 years in a JD Power study.

Maybe it's get sold to someone who recognizes what they may have with a little work.

[carcrazyguy]

1. Too bad. The 1995 G50 was judged the best made car after 5 years in a JD Power study.

2. Maybe it's get sold to someone who recognizes what they may have with a little work.

1. I totally agree, as I am the world biggest car person, and have owned virtually every "10 best" car from the late 80's / early 90's. For that matter, I believe I was the one that talked him into a Q45, as he was looking to get an LS400 when he buoght it.

2. Yes, it would be a perfect car for the type of people on this forum.

[elwesso]

Really the determining factor in taking the plenum off is how bad the hoses are. I would be really nervous on my car (and wouldnt do it on someone elses) without having a full hose kit sitting by me!

Unfortunately most the crap thats hooked onto the plenum is on the drivers side so you might as well remove the plenum all the way. Then you might as well replace the hoses and KS.

$1000 and you'd be left with a pretty reliable car, but it may not be worth it or you may not have the time.. If its clean, I might try and sell it without replacing the injector..

[maxnix]

As wes confirmed, with a litttle attention to known wear items, the car is absolutely bullet proof. Anything short and you are jsut waiting for the next system failure and hoping it is not fatal even if it is inconvenient.

[carcrazyguy]

1. Really the determining factor in taking the plenum off is how bad the hoses are.

2. If its clean, I might try and sell it without replacing the injector..

1. This was a south car since new, and has probably never seen more than half throttle, so the engine bay looks like a 3 year old car...all hoses look really good. Well, I did notice a couple small ones that could stand to be replaced however. Guess I will at least give removal of the plenum a try.

2. It's slightly above average cosmetically, but has high miles as well as a wear spot in the driver's seat, and a pretty decent scuff on the rear bumper.At best it is probably a $2800 car, maybe $2000-ish as it is currently. I agree it might make sense to sell it now, but he simply wants to keep it - and will continue to do so fixing the bare minimum. But we all know this is only the beginning of issues as time goes on.

[carcrazyguy]

Does anyone know if older injectors (from say a 90-93 car) will work? The car is a 94...and I know that is a year where many changes were made. My local pullapart has a couple of the earlier Q's...

Today I spent a little time with the plenum. Got it to lift up pretty well, but could not get it fully off (due to some hoses undeneath that seem as if they would be very difficult to remove).

I also tried to remove a fuel injector, but ended up breaking the plastic on it. Is there is trick to this, or do I need to remove the rail and push them out from the bottom?

[goody90q45]

I also tried to remove a fuel injector, but ended up breaking the plastic on it. Is there is trick to this, or do I need to remove the rail and push them out from the bottom?

Using a noose has worked well for me. Spray the top sealing surface with a penetrant and rotate the FI a couple of times to loosen it up first.

Does anyone know if older injectors (from say a 90-93 car) will work? The car is a 94...and I know that is a year where many changes were made. My local pullapart has a couple of the earlier Q's...

Only FI's from a 94-96 will work for you. They're a little tougher to find than the 90-93 FI's.

[carcrazyguy]

1. Using a noose has worked well for me. Spray the top sealing surface with a penetrant and rotate the FI a couple of times to loosen it up first

2. Only FI's from a 94-96 will work for you. They're a little tougher to find than the 90-93 FI's.

1. I sprayed penetrant, but could only rotate it maybe 1/4 turn and it was still stiff. I then got impatient and broke it (with plyers). Will it still work with some of the top plastic gone? FWIW, I have pulled many a FI and never had one so stuck.

2. DOH!!! Guess this is gonna get expensive! Out of curiousity, is there possibly any other Nissan that uses the same injectors as 94-96? I find a that lot of Nissan parts are universal (especially on the interior). Wishful thinking?

[3Q Jay]

look at goody's picture above. i put the two hold down screws in finger tite and then use them as a fulcrum while putting small flat blade in hole on each side of injector. brisk pressure rather than building up seems to pop them well.

check ebay for 3 used unknown pedigree prupletops for $55 shipped right now.

[carcrazyguy]

look at goody's picture above. i put the two hold down screws in finger tite and then use them as a fulcrum while putting small flat blade in hole on each side of injector. brisk pressure rather than building up seems to pop them well.

check ebay for 3 used unknown pedigree prupletops for $55 shipped right now.

I will try that. I saw those on there last night...will try to get them.

[carcrazyguy]

Hey, just an update...I have gotten to the point where I can get to the injectors (somewhat). I have been able to get the caps off of the ones I need to replace, but for the life of me I cannot get injectors out, even using the two suggested methods. I totally destroyed one of them trying...

Any more ideas?

[maxnix]

Remove the plenum, then the fuel rails.

Doing it right at least once is better than trying to short cut it without ever having done it in my book.

[carcrazyguy]

Remove the plenum, then the fuel rails.

Doing it right at least once is better than trying to short cut it without ever having done it in my book.

Wish I could get that off. There are a couple hoses underneath that I simply canont see how to get off, as well as something (that cannot be seen) holding the back of it on. Since I am doing this for someone else, it is hard to sell the idea of simply cutting hoses, yanking, etc. to get it off either.

Also, as mentioned before, I only have limited time to work on it - maybe an hour here, an hour there - as it isn't my car, nor at my house.

I have already taken so much off (and lost odds and ends that have fallen into no man's land) I will be lucky if all is working when I get it back together. Yes, I should have simply listened to elwesso when he said one should sell it before messing with the injector, but now I am committed...the car stuck in one spot partially apart.

[maxnix]

Read the relevant posts in IOM, and study Ceningolomo's pictures. Then study the FSM.

It is not a job to be done carelessly nor in haste. Your friend will have to suffer. Have him canel the liability insurance for couple of weeks.

[elwesso]

The only way you're going to be able to do this without killing everything is to take the injector rail out or at least enough so you can get to the tip of it and pop it out from the bottom!

if you pry and bang youre just going to be destroying the fuel rail anyway.

The things thats are probably hold it on is the bracket for the IAC vacuum tube under the TB and the hose in the back behind the IAC. After that you should be able to move it around a little more, especially by removing the one under the TB.

[3Q Jay]

right.also don't forget that there are TWO biggish air hoses on the back. one for the AAC and one for the plenum proper. the pleunm one has kind of an 'U'. it also has 1 bolt (2?) near the back of #7 lower runner that is attached to the lower runner. you have to undo that bolt to get the upper plenum off.no way to extract fuel rails w/o plenum removal.after they are out, easy to mash the pintle with a drift to pop out from back side. yes i've sacrificed some marginal injectors that way.



this didn't show as much as i wanted, but it was handy. the pipe that comes around to the bottom of TB area on right is likely your problem child. outside the picture to the bottom center would be where the other end is still attached to the backside of plenum near aac.

[elwesso]

can you use the 10mm socket trick on the 94 injectors [put a 10mm socket on the base of the injector and tap it out]? I know you can do it on the early ones but Ive never had an instance to try it with the later ones?

[maxnix]

Notice how dirty the inside of the plenum is and imagine the results from cleaninig it and the lower intake runners to as new!

[3Q Jay]

Wes, i think an 8mm would be about right, haven't tried.