Plenum Job Finished-Arrrrrrgh!

Post by **Highway Q45** » Sun Jun 08, 2003 3:27 pm

I just "finished" my first plenum removal and went to start the car...stutter, race, flood. Must be a vacuum leak right? The repairs were all due to a No. 4 injector failure. I can only work on weekends so the Q's been out for 2 weeks. I installed all new water and air hoses, gaskets, had all the remaining injectors cleaned and installed new O-rings, tanked the plenum, and cleaned the TB. I get out the trusty inspection mirror and of all the the possible hoses to slip off, it has to be that large elbow air hose to the rear of the plenum under the IAC; it had disconnected at the plenum stub-out during that tedious process of reconnecting 8 gazillion hoses. I know now why I don't like those OEM type hose clamps; should have bought a worm-gear type but I was too tired to go to the store again. Now I have to drain coolant, remove the IAC, and try to muscle that hose on again without raising the plenum. Sorry but I just have to vent. Thanks to all who have done this plenum work before (you have my respect!) and offered so much help and instructions. I'm bruised, beat up, and think I'll just kick back now, calm down, and have a cold one. Tomorrow night the plenum saga continues and hopefully ends!

Steve

Post by **DAEDALUS** » Sun Jun 08, 2003 3:27 pm

Almost there! I've had some luck using the "dental pick" type of tools for getting hoses on fittings that were a little hard to reach. Stab the sharp metal hook into the hose near enough to the end of the hose that it won't cause a vacuum leak, and pull and tug the hose into place.

Post by **911/Q45** » Sun Jun 08, 2003 3:27 pm

You can unbolt the plenum without disconnecting any hoses or draining coolant. It will lift enough to let you wiggle that hose back into place. Stay cool!

Post by **AZhitman** » Sun Jun 08, 2003 3:27 pm

Steve, you're a stud!

Well done - Glad you made it through!!!!

Post by **Highway Q45** » Sun Jun 08, 2003 3:27 pm

911,It seems when I was removing the plenum that there was hardly any lift < 1/2" without removing the AAC; especially with the metal tubing under the plenum bolted up. I'll try your idea if I can't get to it the other way. Getting a worm drive hose clamp on is going to be the hard part. I took many good detailed photos I can put into Power Point or can foward to someone if they want. I don't know how to post them here. Just showing the before/after TB and plenum cleaning is an eye opener. Turns out my PCV was also plugged, EGR crudded up, and most vacuum lines were very oily because of it. Anyone know the correct torque for the plenum bolts, I couldn't find it in the manual. I bet those bolts are real easy to break off. I found the most valuable tools to be dog-leg needle nose Visegrips, magnetic and pincher pick up tools, hose picker, a rare earth magnet to slip into to bottom of my sockets, and a great 1.5" x 9" flexible natural bristle brush I found for the plenum. Oh yeah lots of beer for the daily recovery period.

Post by **911/Q45** » Sun Jun 08, 2003 3:27 pm

You might have to disconnect a few things on the passenger side, but it's worth it! I'd stick with the factory clamps, as the worm drive can loosen after a while. The factory clamps keep spring tension on the hose. Torque for the intake bolts is 11-18 ft lbs.

Post by **Jesda** » Sun Jun 08, 2003 3:27 pm

What's a plenum?

Post by **elwesso** » Sun Jun 08, 2003 3:27 pm

The silver, spidery thing with the infiniti logo atop...

Post by **Q45Viper** » Sun Jun 08, 2003 3:27 pm

Just remember to keep applying beer at regular intervals to keep the recovery period going, you are my hero, I think this particular job is the hardest thing I have read here! Keep us posted!

Post by **elwesso** » Sun Jun 08, 2003 3:27 pm

I am sure it is.....

Post by **Highway Q45** » Sun Jun 08, 2003 3:27 pm

It' Alive! That $3.00 air hose that came loose took me longer than I'm willing to admit. Finally got it back together tonight after lifting the plenum again a full 2" to get enough clearance. There's a place in Hell reserved for the designer of that fitting and hose set-up. It idles fine and revs smooth but I need to replace the AAC gasket again..I dropped the new gasket (insert laugh track)between the firewall and engine and watched it slide into the dark abyss above the transmission...compressed air didn't help dislodge it so I used the old torn one. With my run of luck I don't want to gamble on a road test at night. It's funny, but I think I could do it again in half the time...right after I run bamboo shoots under my fingernails! My hands look like I've be grooming badgers for a living. Now I know why Dennis said he has the "other" techs do it at T-3...he's even smarter than I thought.

So tell me Oh Wise Gurus of Pain, is there a more frustrating Q repair than the plenum that lurks out there? Sign me up, I still have a few quarts of blood to left to give.Steve

Thanks to everyone for the encouragement and to those who talked this old fool through this, couldn't have done it without this great forum and it's knowledgeable members. THE BEER'S ON ME!

Post by **DAEDALUS** » Sun Jun 08, 2003 3:27 pm

Congrats! I don't think anything I've done on the Q is quite as frustrating as R&R of the plenum, but other jobs can take more time (chain guides). Perhaps Forecast has a different opinion, after pulling and rebuilding his engine. When you say "$3 air hose" I have to wonder if you didn't get a factory hose?

Post by **Highway Q45** » Sun Jun 08, 2003 3:27 pm

Daedalus.I bought all new OEM from Joe except for the brake booster lines(3/8 vacuum rated heavy hose). The OEM design was part of the problem. Those short elbow hoses have that anti-collapse metal tube lining at the bend. I had attached mine to the lower metal tube 1st and then to the plenum. I hadn't lined it up perfectly and it was oriented too close to the plenum when I replaced everything. There's almost no play once it's clamped down. Next time ??? I'll connect it tight to the plenum tube 1st and the lower tube 2nd...live and learn. I also know now that you can raise an assembled plenum pretty far by just disconnecting the AAC, EGR @ the flare, intake bellows @ TB, the front PCV hose, and the passenger side plenum to cam cover hose. I also broke off one of those shouldered plenum hold down bolts, those things don't take much to break or I had a weak one...the stub came out easy.

Funny you should mention chain guides..after pulling the center front cover I found that the chain covers are "blue" RTV and the water pump is "red" RTV. Guess I have a new water pump only and new guides probably haven't been done yet. I think I'll take a rest and enjoy life for awhile before starting that one.

Post by **DougQ45** » Sun Jun 08, 2003 3:27 pm

Welcome to the Plenum club. I understand your remorse, having dropped things into places they can't be retrieved from .... when I replaced that one stinking injector!!!!! The chain guide is much fun compared to the plenum. Makes you feel like part brain surgeon, part Ferrari tech.

Post by **elwesso** » Sun Jun 08, 2003 3:27 pm

How hard is it to remove the plenum, and not replace the hoses (all my hoses seem to be OK, everyone i have felt has been soft and plyable; not rotted)

Post by **AZhitman** » Sun Jun 08, 2003 3:27 pm

Wes - They deteriorate from the inside out - No real sane reason not to replace 'em.

Joe sells a kit that makes it easi(er). Plenum job is a big one, plenty of posts on "plenum removal".

Post by **Highway Q45** » Sun Jun 08, 2003 3:27 pm

Wes,You might be able to save a water hose or two (I wouldn't) but DO make sure you replace all of the under plenum air hoses. The 3-way air hose at the AAC doesn't have to come off so you might be able to save it if isn't hardened up yet. Joe at Scottsdale was kind enough to include a factory drawing showing air and water hose placement. Some of my air hoses were so hard I thought they were steel tubes until they split apart at the fitting. A racheting PVC pipe cutter works great and saves time to cut hoses if you know you are replacing them all. Cleaning the TB and plenum is easy once it's off. I found that TB cleaner evaporated too fast for the plenum. I used "Grease Eater" first, rinsed with water, then Easy Off oven cleaner for the final cleaning of the plenum. I've used the Easy Off for years on the Miata. It looks like brand new now. Use TB cleaner or solvent only for the TB and don't let it soak in too long around the TB plate-shaft seals. Stock up on knuckle bandages!

Steve

Post by **Jerry Parks** » Sun Jun 08, 2003 3:27 pm

I just had to remove the plenum to replace the approx 1 and 1/2 inch 3 inch water hose under the plenum. I wouldrecommend that you replace that hose as well. Mine sprunga leak on the highway and almost overheated my engine.

Post by **maxnix** » Sun Jun 08, 2003 3:27 pm

Jerry Parks wrote:I just had to remove the plenum to replace the approx 1 and 1/2 inch 3 inch water hose under the plenum. I wouldrecommend that you replace that hose as well. Mine sprunga leak on the highway and almost overheated my engine.

All hoses should be replaced when the plenum comes off, unless they are all brand new. The labor is the killer, unless a hose fails. Then it's your engine that could die.

Post by **elwesso** » Sun Jun 08, 2003 3:27 pm

If you are going to go to the trouble of taking the plenum off, its stupid not to replace all the hoses!! The plenum is hard enough to get off... no sense in having to do it again because you didnt want to replace the hoses!!!!

Post by **Jerry Parks** » Sun Jun 08, 2003 3:27 pm

you got that right. Removal of the Plenum is hard work and sonewhat frustrating to say the least

Plenum Job Finished-Arrrrrrgh!

Plenum Job Finished-Arrrrrrgh!

Re: Plenum Job Finished-Arrrrrrgh!

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