Plenum removal and other scary thoughts

[DrewQ45]

90Q, berry, clean as a whistle with 170K.

Hi folks,

A few of you might remember me from the yahoo days. I've posted a few times on Nico but that was waaay back. It's good to see that the Q's are still alive and kicking as mine is.

The warm weather and rain in Atlanta has me spending time in my Garage and eyeing my Q under the hood while taking short breaths as a weightlifter about to pump major iron would do. My last big job on the Q was when I changed the alternator. As I reminisce over the "simple" task of changing the spark plugs, I shudder to think of the task I'm about to undertake. Not only will I be changing the plugs again but I am also going to change all the hoses under the plenum. I waited purposely until I needed to change the plugs again so the agony would not be repeated. Having peered down into the cavity betwix the legs of that big spider with a small flashlight, I was surprised to see a liquid, which seemed to have the consistency of thickened blood pooled into the cavity. (Oh no, my Q is bleeding from the heart!!!)… My first thought was transmission fluid but I had no idea how that would get there. After exploring the depths with a small mirror, I found that one of the coolant hoses had a small drip and was leaking the Toyota Red coolant ever so slightly into the recesses of the interior. I tried using magnets and those long slender part retrievers (the kind you use to pick up dropped nuts and bolts in hard to reach places) to slide a screw clamp over the hose end (so I could prolong my putting off the job), but that damned Budweiser keeps messing with my dexterity. Maybe I need to put the can down first? (perish the thought)… I have performed searches on this great site so I could get the techniques and perspectives of others but I still have some questions regarding plenum removal. Keep in mind that everything must be OEM.

What do I need to change aside from hoses? …. I never want to do this again. Should I just go ahead and change the 4 injectors that sit under the plenum? (The car runs great)... If so, what is the best deal out there for OEM injectors and anything else that might be suggested? What kind of liquid do ya’ll soak the plenum in? (don’t you dare say Beer)How about Knock sensors? Costs and best place to buy OEM. OEM Plugs...best place to buy??? Last time I changed the plugs, (60K ago) some were sitting in a pool of oil...Guess I need seals???

Next, I will change front wheel bearing on drivers side...Already have the part sitting for a year now.

Hmm...what else?... Oh yeah... Extreme inner edge wear on driver's side front tire. (passenger side too but worse on driver's) ...looking at the tire you'd think it was still new except for the ribs sticking out on the very edge. Please feel free to comment on that too. I'm sure the 18" wheels do not help at all but I'm stuck with those for now. At last alignment I was told this type of car could not be shimmed... but the posts seems to suggest otherwise.

Haven't changed much... I still obsess over cost... I’m the king of Q on a budget. Guess I can't stand the thought of that damned Q slappin the food out of my kids' mouth. But then again, I can't do without the beast and it's growl! Oh how I love her. (damn them kids)

Holla back... TIA

..Drew....

[nuQ]

drew- other than the kids, i'm with ya about my Q (i only take food out of my mouth!!!). also thinking about a plenum clean and replacing all the hoses. how about the throttle body and a complete pressurized rail clean. could anyone tell us the best order of importance. i'm sure drew, you'll find the best prices at scottsdale infiniti,,definitly call and let them know you're a NICO member though, no email (found out the hard way!). jeff

[landtodd]

Gosh, Drew, long time! Welcome back.

Drew said "Last time I changed the plugs, (60K ago) some were sitting in a pool of oil...Guess I need seals???"

Geez, I've put 10K on mine since last time you changed your plugs. Do you live in the car? j/k

Well, ya know, the '90 cam-cover seal is just RTV. Nice idea, but it doesn't work all that well after a couple of years. Cam covers are a PITA, of course. A mess to put back together. I'm thinking about trying the later-model gasket, myself. It'll be a lot easier with the plenum off. Very good call.

Knock sensors? If the car has ever overheated, or you're going to keep it forevermore, sure. Replace all coolant hoses. Scottsdale calls them the coolant-bypass kit. I had the same coolant leak causing me to do just what you're doing.

Also, get a tool from your Matco dealer that looks like an icepick with a hooked end. Useful for reaching under the edge of hoses to hopefully break their seal with pipes. You may be able to reuse a couple of non-brittle hoses that you otherwise would have cut? I bought another one today.

[forecast]

Infiniti of Scottsdale (http://www.infinitipartsusa.com) is the best source for OEM parts, but CALL and mention NICO.

They sell two kits - a water hose kit and an "under plemun hose kit" both are necessary, the second is mainly the PCV hoses.

NGK plugs - about 8.25 each from scottsdale

Arm yourself with info on the injectors before replacing them - ohm them all, check the harnesses, maybe even a power balance test at the local Nissan or Infiniti dealer. No sense burning $500 on four injectors you don't need ( that's a lot of happy meals!)

If your plugs are bathing in oil, thats troubling. It comes from the valve cover. That seal comes out of a tube. Maybe, tightening down the cover will stop the leaking, but to be safe, pull the cover and reseal it. If you've got the plenum hoses lose and the plugs out, you're half way there already anyway. If two ounces or more of oil runs into the cylinder you could potentially have a hydrolock situation and bend a rod at startup.

[911/Q45]

Replace the air, fuel and vacuum hoses under the plenum while it's off. That's a lot of rubber, but as you said, you don't want to go under there again.

[AZhitman]

Drew, glad you're back - We missed ya!

Looks like you have your work cut out for you, but you're going at it the right way. Get all your parts from Joe and go to town.

p.s. You wanna swap those 18's for some factory chrome alloy 16's?

[Q45tech]

Don't think the hoses will last forever, even replacements.Changed all mine at 75k and again at 180k, with 249k I am looking forward to another round in a few years.........the joys of the warm South.