Removing Intake Collector on 1994 q45

[xeooex]

Ok, I am and ASE mechanic, but i normally work on fords. Helping a friend by working on his q45, he said Infiniti diagnosed the vehicle and said no 5 injector has low flow, and he needs to replace the injector, he wants to replace all 8. he has a service manual, but i cant find clear instructions on how to remove the upper intake portion, i have removed it but think i took the long hard way. What i want to know is, are all the tubes and vacuum tubes attached to the bottom, supposed to stay on the intake? i raised it up and remove the 10mm bolts, then slowly but surely unhooked all the hoses i could see attached. After looking at it, looks like it supposed to come out as an assembly. Am I correct in thinking that? also is there an easier way to get the fuel rail out? i had to fight that too. but my final question is how do you remove the injectors? Just push them out? or is there a special tool? Any help is greatly appreciated, or if anyone has the workshop manual section on removal/install i can give a fax number or my e-mail is [email protected].

[goody90q45]

I think you're talking about the exhaust gas manifold under the plenum that all the 3/4" hoses feed into. It helps to remove the 10mm bolt on the driver side closest the firewall that holds this manifold to the plenum. From there there's 1 or 2 more 10mm bolts on the underside holding the manifold to the plenum. As long as the back bolt is removed the manifold can stay attached if all the hoses coming into it are disconnected.

If you have the fuel rail out of the engine injector removal is pretty easy. I have a drill press so I set up a wood jig and push them out from the bottom. Lube both ends with a good penetrant first, rotate it a couple of times in the cup, and use a dense rubber pad on the pintle end of the FI so you don't damage the cap. If it's rotating freely you may be able to pull each out by hand.

If you don't have a drill press, pad a 2 x 4 and holding the fuel rail on either side of the injector you're removing, push firmly from the bottom. It should pop out.

[Q451990]

http://www.phatg20.net for the FSM. Check out http://www.q45.org/plenum.html and zer...tures for articles on plenum removal. One is for the earlier 90-93, but it's pretty close.

Good luck!

Heath
Modified by Q451990 at 5:06 PM 10/12/2008

[xeooex]

Thank You so much that was exactly what i needed. Def went the hard way about it. lol do these things typically have injector issues? and he was told they cost like 300 a piece. is that true?

[Q451990]

The 90-96 Q45's are dropping injectors rapidly since the widespread introduction of E10 earlier this year. I just replaced all 8 of mine with aftermarket injectors by BWD - which are supposedly able to withstand E85 (although the rest of the fuel system can't) - but I have about 150 miles on them, so not enough trial time to say for sure.

Check out the article at http://www.q45.org for ohm testing instructions... since you have the plenum off, you can just check each injector directly instead of through the subharness.

New ones are not $300... more like $180 from http://www.everythinginfiniti.com for OEM new... and I spent a little over $100 each for the aftermarket units. http://www.deatschwerks.com also supplies remanufactured units, and can clean and flow match the full set for you.

When I had a couple of full fledged failures on my old Q (this one had a couple of intermittant issues only) the corresponding spark plug was badly fouled... so if you put everything back together and still have a dead miss, I would check there - or you could go ahead and replace the plugs while you have everything apart. OEM NGK is highly recommended over anything else - especially Bosch.

Heath

[xeooex]

So should he go with the aftermarket injectors, for ethenol reasons? Also do they make a hose kit? Like a kit with all the form fitted hoses for the emissions system, underneath the plenum, and do they make a intake gasket kit? Not familiar with these cars so trying to make sure i get everything i need. Would like to replace all the hoses under there but not sure what some of them go to. Thanks alot for all the help guys, this is got to be the coolest forum i have ever been to for cars. normally by now i would be getting flamed big time, and no help would be given. Props to Nicoclub.com
Modified by xeooex at 8:33 AM 10/13/2008

[Q451990]

Thanks for the compliments on NICO! Next thing you know you'll be changing dealerships to work on these things all the time!

As far as the hoses, I would call Infiniti of Scottsdale (www.everythinginfiniti.com) and talk to Bill. 1-888-216-5328 They have all of the under plenum hoses and the gaskets that seal it to the runner. They sell at wholsale prices to the public. As a technician, you can probably get the same prices at your local dealership... but I think they are offering an extra 5% off this month that might offset the shipping cost - and their customer service is first class!

You're looking at about $1000 - $1500 to replace everything under there (not including injectors) - but it's the way to go if your friend is going to keep the car for a while. You also want to replce the knock sensors and it's harness if the sensors are cracking. You won't know until you pull them and can look at them closely.

Hard to answer your question on the injector issue. I have been running the aftermarket injectors for about two weeks, and I'm the only one on here that has been running them as far as I know. So that doesn't speak to how well they will hold up long term. I think I would ohm test them first and see how many are out of spec. and then decide from there. The big problem is that one can ohm fine one day and then crater the next - so there are no guarantees, except that replacing all of them should buy you a few years.

Good luck!

Heath

[xeooex]

Hey I'll change dealerships if the money is right. lol Seriously though this is a well put together site and it has been very helpful in my adventure so far.

[jimbyjimb]

Yeah, you're lucky none of the cranky old farts got to you first. 1990 is about the nicest and most helpful guy on here, never is a jerk to anybody and actually will answer your question instead of telling you everything you don't need to know. So thanks from me too. But you will find, even the cranky guys, have years upon years of experience in dealing with the Q specifically, especially G50, and when willing to part with useful info it is in fact EXTREMELY valuable. Searching the past posts for info can be helpful as well. Things like the timing chain guides, and whatnot. Don' have to worry about that in 1994,however.