FGY33 Plenum Removal, *Finally, a walkthrough for the 4.1*

[redZENKI]

Anyone know what goes here? ( I've circled in red). I'm putting the car back together I can't seem to find what screws into here.

[paranoidjack]

don't remember, but one thing I can tell you is these things "find themselves" as you re-assemble. I think it's a bracket mount of some kind if I remember correctly. Don't worry about it until you are at the point of making it inaccessible, that's my golden rule.

[redZENKI]

ok cool. i'm going to be finishing putting things together here probably tomorrow. is there any tips on things to do before i start the car up? for example, i had the injectors serviced so i'm wondering if i need to get some fuel pumped through them first. i'm fairly inexperienced auto mechanics so any help would be great.

[paranoidjack]

As for the injectors, I didn't!

Other than that, double check oil level, coolant, and ALL fluids...run for a few minutes carefully watching for leaks, etc...pay close attention to gauges, don't let the car overheat from air pockets in coolant. Follow FSM procedures for bleeding system of air.

[maxnix]

Yes, pressurize injector rails before installing them. Many rebuilders do not test their rails as a unit including some recommended in this thread.

Pull your fuel pump fuse before initial cold start and turn for 20 seconds to pressurize and lubricate. Replace fuse and start.

Do not assemble non-cleaned plenum parts nor leave dirty assemblage together by using the "shortcut" method. There is no shortcut to manual cleaning.

[redZENKI]

Ok, tried to start it last night before I saw your post. I didn't pressurize the injector rails before installing them or pull the fuel pump fuse before the initial cold start.

Car tried to turn over last night, but not getting enough fuel pressure maybe? Fuel pump fuse is good. Fuel pump was good before I did the KS replacements. Car was sitting for a few months as I was out of the country. Any ideas anyone?

[redZENKI]

I'm also getting the battery tested today since it was sitting so long. Battery was dead after 3 attempted starts. I'm hoping it no longer can hold a charge and that's turns out to be my problem. lol.

[maxnix]

Battery is Tango Upsilon.

[redZENKI]

Ok so, battery is good. Car tries to crank, but doesn't turn over. I can hear the fuel pump come on when I turn the key. There's also fuel coming out from between my throttle body/intake piping where the clamp is.

Any ideas?

[maxnix]

God, I wonder if he blew himself up?

[paranoidjack]

Lol! Let's hope not.

[VA99Q45]

think he is OK, just his engine that blew up.

[S7Zero]

This question may have been posed before, but what are the chances of being able to bypass the original knock sensors altogether? With two new sensors, mounted in more accessible locations on the engine? I know of people using this method with other Infiniti and Nissan models. I suppose it would depend on where the wiring harnesses connect...

[paranoidjack]

Some people have reported success installing appropriate resistors instead of the KS's. I'm an OEM guy, and there are good reasons to do this large project aside from KS's, though it could be an easy solution to get inspected or something like that.

[maxnix]

This question may have been posed before, but what are the chances of being able to bypass the original knock sensors altogether?

You can put them anywhere else you want to, but they will not function.

[S7Zero]

This question may have been posed before, but what are the chances of being able to bypass the original knock sensors altogether?

You can put them anywhere else you want to, but they will not function.

Why is this the case with the Q45, but not...say...the J30? There's a nice video tutorial on Youtube of a J30 owner mounting a new knock sensor on a random spot on the engine and connecting it to the original knock sensor's socket...worked for him. I think what I meant to ask was, where do the knock sensors "plug in"?

[paranoidjack]

What Brian is saying is that the knock sensors will be powered, and send an "OK" signal to the ECU, but will not function as intended. They are designed to "listen through" the block and listen for pinging and improper detonation, and then retard the timing to reduce chance of catastrophic damage.

Many people feel they are needless, but in rare situations they will save an engine. Very rare situations.

[S7Zero]

Ah, I see...a valid point, but I suspect they might still serve their purpose if bolted *somewhere* on the engine, especially considering how smoothly it runs normally (wouldn't take much of a knock to register outside of "The Norm"). I just can't see myself tackling even the "Option 2" method lightly, and am seeking an easier fix. Does anyone happen to know where the wiring harness/socket is which the knock sensors connect to? I can look the next time I have the engine cover off, but I thought I'd ask.

[Wiggler]

PJ, I sent you an email (disregard)... Well, so I am right now at the stage of removing the lower plenum, it seems really stuck on there... I've removed all of the bolts on the sides and that fuel line bracket in the back close to the firewall...









the only thing I have not removed is the bracket with some hoses and that solenoid on the underside of the lower plenum... but I can't see that thing preventing me from lifting the front of it up. It seems to move a little bit when I try to lift it up...but not much at all... and definitely not enough to access the 10mm bolts on that underside bracket
MY question.... is the plenum stuck on the gaskets and should I just use force to tug it off??? I can't see any hidden bolt based on the pictures in this thread...
I even got on top of the motor with one foot on the frame by the radiator and one on the strut bar bracket and pulled straight up....no dice!!!
oh also... the plastic tabs surrounding the fuel injector nozzles on the passenger side rail did not make it... do you guys think this is a huge problem in function after reassembly???

[paranoidjack]

Sorry Wiggler didn't even see the email - just checked again, didn't receive...

paranoidjack (at) comcast.net?

Anyway,

I took a close look at all 3 pics. Though it appears you have everything, there's always something hiding. Give it a smack from the side with a hammer (it's aluminum, be careful, not hard enough to break your arm if you hit it for example) and see if it "breaks" from the gaskets. The gaskets are thick rubber and as I recall had *zero* bind, so it sounds to me like something is still connected. Does it lift up in the front or back more? Left or right?

Double check all bolts, there's always one hiding, and pay close attention to behind the plenum. Sounds to me like you're binding a rubber line, coolant or vacuum. Easy to do. You may have to remove the terminal end of one of the vacuum lines going to the MAP/BAR sensor (the one on the bracket mounted underneath). I'd STRONG suggest LEAVING it connected under the plenum runners, and disconnecting the other end, not the one at the bracket under the plenum.

Oh, and those plastic things are called pintle caps. Yeah, it stinks when they break. Not the end of the world but they (I think) are designed to give a cleaner and more consistent spray, thus also reducing the chance for seepage around injector orings.

Had the same problem:

http://www.youtube.com/watch?v=plbvv77tKHk

PS those fuel lines were a b**** huh?

[Wiggler]

Hey PJ.. thanks for the replies... in your thread and mine... hey listen, the guys at Infinitipartsusa are having trouble finding out which part numbers correspond to the EGR valve gasket and the tube Gasket from the upper plenum.... the tube gasket is the one that's bigger, right???