Does the EGR valve need to be disconnected to remove the plenum? I'm not able to tell exactly by looking at it, but it looks like a pain to remove so I'd like to skip it if possible. Can I just disconnect the pipe coming from the rear of the engine bay, like in the pic below?
Plenum Removal Question (90 Q45)
Re: Plenum Removal Question (Q45tech)
Yes to the last part?
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maxnix
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1995 Infiniti Q45t
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Re: Plenum Removal Question (frenetic)
Do spend some time reading the under plenum hose job posts, You will learn a lot!
Start here, but clean your engine better!
zerothread?id=212964
Start here, but clean your engine better!
zerothread?id=212964
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goody90q45
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Re: Plenum Removal Question (frenetic)
Once the lage pipe is disconnected there's only two 12mm bolts left to completely remove the EGR. If you're going through the trouble of removing the plenum you'll want to clean it up and you can't do it properly with the EGR valve attached.frenetic wrote:Does the EGR valve need to be disconnected to remove the plenum? ........it looks like a pain to remove so I'd like to skip it if possible.
Re: Plenum Removal Question (frenetic)
Swear words.
So I have most of it off, my goal here is replacing the 5 and 7 injectors. I have sliced several hoses on my quest but think I've managed to get by with minimal damage so far. Now I appear to be stuck. This is the first time dealing with injector replacement of any kind, so pardon these questions if they're a little stupid.
This is where I am at. I can get to the #5 with minimal problems, but #7, at this stage of plenum removal, is it possible to replace? I keep reading about how hard that center hose in the back is (and mine appears to be clamped with a screw clamp, with the screw head facing the FIREWALL....)
So, is it possible to replace the #7 injector from here? I'm not going for a full engine overhaul, just want to get my car running nice again. I'll be replacing 5 or 6 hoses here as well, changing my spark plugs, cleaning the EGR valve as has been recommended, replacing a few gaskets... I'm sort of working around as I look at it to see if that #7 is replaceable here, and I think it may be... any tips?
So I have most of it off, my goal here is replacing the 5 and 7 injectors. I have sliced several hoses on my quest but think I've managed to get by with minimal damage so far. Now I appear to be stuck. This is the first time dealing with injector replacement of any kind, so pardon these questions if they're a little stupid.
This is where I am at. I can get to the #5 with minimal problems, but #7, at this stage of plenum removal, is it possible to replace? I keep reading about how hard that center hose in the back is (and mine appears to be clamped with a screw clamp, with the screw head facing the FIREWALL....)
So, is it possible to replace the #7 injector from here? I'm not going for a full engine overhaul, just want to get my car running nice again. I'll be replacing 5 or 6 hoses here as well, changing my spark plugs, cleaning the EGR valve as has been recommended, replacing a few gaskets... I'm sort of working around as I look at it to see if that #7 is replaceable here, and I think it may be... any tips?
Re: Plenum Removal Question (frenetic)
Here is a better detail of the hose clamp on the IAC inlet..
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goody90q45
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Re: Plenum Removal Question (frenetic)
That's a tough enough hose to get to without the clamp being backwards. Can you pull the plenum forward enough to get a stubby screwdriver on the clamp. With just a couple of turns you'd be able to rotate the clamp and finish unloosening from the front. IAC valve is unbolted, correct?
You're only one hose away from having the intake off so enough with the talk of changing #7 FI with it still on. Many have just cut that hose and replaced with new at reassembly. Good luck.
You're only one hose away from having the intake off so enough with the talk of changing #7 FI with it still on. Many have just cut that hose and replaced with new at reassembly. Good luck.
Re: Plenum Removal Question (goody94q45)
Yeah I will just cut it. I cut a few other hoses, might as well get that one. I stopped for the day a few hours ago before going to far. I don't have a short enough screwdriver as it is to get to the second screw properly on #5 but in looking at #7 it looked like I would be able to set the plenum down into position and unscrew them from between the plenum openings, then possibly prop it up and get at it. Still a tight fit back there and it looks like there's a lot of grease and stuff that could get cleaned out anyways. I'll cut through the hose in the morning.
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goody90q45
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Re: Plenum Removal Question (frenetic)
You're on the right track. Shift the plenum left and right to get to the 4 screws you need removed. Use a long, long screwdriver (12"-16") so you can get a lot of downforce and not strip the screw head.
Stuff a rag in each of the intake runners before you go much further.
Stuff a rag in each of the intake runners before you go much further.
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Q451990
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While you're in there, you really want to clean your plenum and lower intake runners. The inside of the plenum should be the same color as the outside.
Nothing a case or two of brake parts cleaner and a handful of brain cells won't cure!
Ideally you would pull the fuel rails and test them off of the car after you replace those injectors. A leaking lower o-ring can hydrolock and total your engine in seconds if it's bad enough. Also, be sure to use a smear of motor oil on the o-rings and rails to help prevent damage.
Oh, and those injector cap screws strip out very easily. Make sure you're using the correctly sized screw driver, and tap the driver into the screw with a rubber mallet to seat it very solidly before you try to twist the screw.
Heath
Nothing a case or two of brake parts cleaner and a handful of brain cells won't cure!
Ideally you would pull the fuel rails and test them off of the car after you replace those injectors. A leaking lower o-ring can hydrolock and total your engine in seconds if it's bad enough. Also, be sure to use a smear of motor oil on the o-rings and rails to help prevent damage.
Oh, and those injector cap screws strip out very easily. Make sure you're using the correctly sized screw driver, and tap the driver into the screw with a rubber mallet to seat it very solidly before you try to twist the screw.
Heath
Re: (Q451990)
Heh, indeed. Got 3 out but one of the ones I attempted to remove before the plenum was off is stripped, why are these screws so soft? Any tips for getting this one out?Q451990 wrote:Oh, and those injector cap screws strip out very easily. Make sure you're using the correctly sized screw driver, and tap the driver into the screw with a rubber mallet to seat it very solidly before you try to twist the screw.
Well ok nevermind, I picked up a bit for my Dremel to slice a notch in there.. See if the dealership has these screws in stock or something.
Modified by frenetic at 6:13 PM 8/25/2009
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Q451990
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Re: (frenetic)
I clamp on them with a pair of vice grips to get the first turn...
There's nothing particularly special about the screws. I changed all of mine to hex head bolts. In fact Infiniti of Scottsdale used to stock them and all of their techs. just replaced them as a matter of practice.
You can find the correct thread pitch and size at Home Depot or Lowe's if you want to go that route. I found a whole a handful of them with built in star-style lockwashers on them in my dad's garage stash when I replaced mine. Free is good.
Heath
There's nothing particularly special about the screws. I changed all of mine to hex head bolts. In fact Infiniti of Scottsdale used to stock them and all of their techs. just replaced them as a matter of practice.
You can find the correct thread pitch and size at Home Depot or Lowe's if you want to go that route. I found a whole a handful of them with built in star-style lockwashers on them in my dad's garage stash when I replaced mine. Free is good.
Heath
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maxnix
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Re: Plenum Removal Question (frenetic)
Three points:1.) It is much easier to extract and replace injectors without damaging them with the whole fuel rail on the bench.
2.) Look at the condition of your lower runners, then look at the interior of your plenum, then look at the valley of the V8. Are you you going to reassemble them in that condition?
3.) Don't assume any hoses, especially coolant hoses, are OK from examination of their exterior only!
Read some more threads on plenum removal and hose replacement and you won't have as many questions.
2.) Look at the condition of your lower runners, then look at the interior of your plenum, then look at the valley of the V8. Are you you going to reassemble them in that condition?
3.) Don't assume any hoses, especially coolant hoses, are OK from examination of their exterior only!
Read some more threads on plenum removal and hose replacement and you won't have as many questions.
Re: Plenum Removal Question (maxnix)
Thanks for the tips. I have been reading every injector and plenum thread I can, only asked things I am confused about. I still have about 7 pages open with info for when I put everything back together. I agree, it's very dirty, and am going through tomorrow with cleaner to get everything I can. I have a power steering leak I need to fix and after dropping a bolt in the engine valley I discovered I have a coolant leak, so I do have things to sort out before I go on. I wish I could replace every hose in here, I would feel a lot better but unfortunately just don't have the money. I am replacing about 8 hoses now, and may end up replacing more, but it's cutting into budget.
I got the 2 injectors out relatively easy, got the new ones in. Going to pick up new screws all around for the injector casings so I don't end up stripping any more.
I will clean the EGR valve before putting it back on...
Hopefully sometime in the near future I can put new hoses on, but just can't do it right now...
Thanks everyone for their help! I'd be lost without nicoclub.
I got the 2 injectors out relatively easy, got the new ones in. Going to pick up new screws all around for the injector casings so I don't end up stripping any more.
I will clean the EGR valve before putting it back on...
Hopefully sometime in the near future I can put new hoses on, but just can't do it right now...
Thanks everyone for their help! I'd be lost without nicoclub.
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maxnix
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1995 Infiniti Q45t
2000 Infiniti Q45
Re: Plenum Removal Question (frenetic)
Take lots of pictures and take lots of notes! And not trips until you get the hoses, KS, etc. brought up to standards. Catastrophic coolant hose failures are not pleasant. And don't judge a hose by it's exterior appearance. Many look good on the outside, feel pliable enough, and are absolutely rotten on the inside. Maybe you can sell some blood?
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