Working under Plenum....

[pabs324]

Sometime this week I'm going to get under the plenum of my 94 Q45 and replace all the hoses, knock sensors and harness, pcv valve, all 8 injectors and fuel rails, gaskets and spark plugs. Does anybody have any last tips other than the plenum removal write up and little things I've picked up here and there?

[qship96]

Take plenty of asprin before starting job to ward off aches/pains, have plenty of band-aids available, and raise car on ramps or stands to limit bending over and backpain.

Oh yeah, have plenty of strong directional lighting at hand and use a digital camera to snap photos before and during disassembly to help you get it all back together with no "extra parts" when you are done!

Never hurts to mark all male/female connection points of hoses/wires upon disassembly to make reassembly quick and foolproof--color coded or numbered sticky dots come in handy as markers

[Q451990]

...last tips other than the plenum removal write up and little things I've picked up here and there?

1) Make a trip to Harbor Freight and buy a box of latex gloves. It's amazing how much they protect your hands from cuts and spare you 15 minutes of hand scrubbing when you're done.

2) Remove the fuel rails to pull your old injectors on a work bench vs. trying to do it in the car. Pressure test the rails after installing your new injectors - and make sure to lubricate the new o-rings.

3) beer

Heath

[maxnix]

Take lots of pictures.

Good luck. Keep us updated.

[pouncer11]

take pictures with captions and make a guide, thats what i plan to do when i go into the jungle. I get paid Thursday which means i get injectors Friday. So anything you find worth telling us about would be awesome. Vaseline for your injectors when replacing them, Go slow, and if your replacing the hoses maybe cut them with zigzags (leave the halves where they are) then you know what hoses go to what and where and etc. Also what gaskets need to be replaced when the plenum comes off?

[elwesso]

the gloves help..

Try to do things in stages.. Try and get to a good stopping point before you quit otherwise you may forget something. In other words, dont stop midway through final reassembly if you can help it. Sometimes that may be hard...

If you are installing injectors into the rails, be sure to PRESSURE TEST THE RAIL BEFORE YOU PUT IT BACK TOGETHER. Even the smallest drip of fuel means the injectors didnt seat right. You'll have to do it a couple times to get the air out of the lines...

Also remember as SOON AS THE PLENUM COMES OFF something goes over the holes on the runners... Either duct tape or shove some paper towels in the hole. Youll want to kill yourself if you drop one of the many tiny parts under the plenum.

Remember we're here for instant support so if you get into trouble, dont assume but ask!

[pabs324]

thanks for everyones advice and im still open for some more... the only thing holding me back so far is the driver's side fuel rail which has been on back order for the last three weeks.

[pabs324]

the gaskets you will need are the plenum gasket,manifold, iac, throttle body and egr. I have the parts number for them if you need them.

And to anyone else, Am I missing any that I should have ?

[Q451990]

Why are you replacing your fuel rails?

Heath

[pabs324]

I figured once I'm under there just replace them as well. It turns out I'm only going to be replacing the passenger side since the other side is on back order with no ETA. Both Joe and my local Infiniti dealer have no clue as to a date so I cancelled it.

[Q45denver]

Fuel rails usually don't wear out. The pressure regulator may depending on miles/dirt etc..

Go slow and don't get carried away when torquing down the manifolds. Remember these parts are aluminum and are easily cracked/stripped.

[Q45tech]

Never replaced a 90-96 fuel rail and never heard of one needing replacement.

They are are generally spotless inside unless corroded with water and that corrosion can be chemically/solvent cleaned easily.

What above KS and fuel injector harness and 2 coolant temp sensors [may have insulating film/crud on them]. If you are going to make it new make the sensitive things new first.

Check your heater hoses [remove and look] for pipe corrosion on heads? so much easier to change with plenum off.

[pabs324]

Thanks for the advice. I have the KS harness but not the fuel injector harness. I'll look into that.

And does anybody have some tips on removing the injectors from the rails?

[pabs324]

What do I need the RTV for

[maxnix]

A couple of spots on the VC covers? The VH41DE requires it. I use a little more very thinly on several curves to keep the gasket from fallin out when installing.

Timing cover if you go that deep.
Modified by maxnix at 9:22 PM 4/29/2008

[maxnix]

Vaseline for your injectors when replacing them,

Those of us who have a little more experience with insertions prefer KY. Really.
Modified by maxnix at 9:22 PM 4/29/2008

[pabs324]

So you prefer KY as opposed to the vaseline. Do you find it easier to maneuver the injectors into the rails or just personal preference?

I've read many different types of lubrication such as vaseline, motor oil and now KY.Which is best?

[maxnix]

KY leaves no deposits. Someone else suggested it. In Deatschwerks I trust. Send them the whole rail.

[jimbyjimb]

Putting a little silicon on the plenum gaskets helps them stay in place when re-installing the plenum.

[pouncer11]

are you making a joke or are you serious?what about astroglide

[Q45tech]

Careful many lubricants contain solvents which are absorbed and attack rubber orings!We just use a slight amount of engine oil which is natural to their environment.

[pabs324]

So a little RTV won't harm anything? I've read that in the FSM it says not to use it.

[pabs324]

Motor oil maybe be the way to go then. I wonder what the dealerships use?

[maxnix]

So a little RTV won't harm anything? I've read that in the FSM it says not to use it.

RTV is not a lubricant.

[pabs324]

I know, the RTV is the silicone.

[Q451990]

And does anybody have some tips on removing the injectors from the rails?

Are you trying to preserve them? If you're not concerned about destroying them, it's easy. Just tap them out by the tips. If you're saving them remove the covers and then soak them with PB blaster.

Check out this link to a 300ZX forum (identical injector design) with a removal method - see step 33 and the next few after that... looks like a great idea, but I don't know anyone here who's tried it yet.

http://www.300z.co.nz/index.ph...id=32

My local dealership uses Vasoline... or at least did in 1998 and 1999. I used it on my old Q and got 80K+, but if motor oil works well for T3, then I think I'd go with that.

Heath

[pabs324]

They all read between 4 - 4.3 ohms so I doubt there would be any reason to preserve them. What is PB blaster and I did read that article earlier today

[Q451990]

PB Blaster is a release agent similar to WD-40, but seems to be the prefered one.

Heath

[pabs324]

do they sell that at hardware stores and will WD-40 work just the same ?

[91-q45]

with the hoses, put a piece of masking tape where the hoses connect to and number them that way you can remember where they go....it may take a little extra time but it will save you a lot of time in the long run....also while you have the plenum off, put a shop rag or two over the ports so debris doesnt fall in there...