Locating vacuum leaks.. And a couple other concerns...

[elwesso]

I have determined that my fast idle problem is due to a vacuum leak (thanks to those who helped me)...

Anyway, when I turn off the car, I can hear the "vaccuming" noise for a second or so..... I havent been able to locate it exactly, but it seems as if its around the TB area..... Also, if it helps, when I first startup the car, it shoots up to 1750 RPM and then hunts for a little bit, and then stabilizes at 1250 (normal fast idle). It doesnt hunt as much when its cold as when its hot......

What is the best way to locate a vacuum leak.... Are there tools I can get (or that the dealer has, I will take it to the dealer if you think it can be reasonably fixed there).....

Also, on a side note, I have a few other things. 1. At startup, there is a loud groaning noise... IT sounds like its coming from the PS area.... There are no air bubbles in the resoviour, and the PS works just fine. Its very faint once it gets to operating temperature, but still there....2. I only tightened the EGR tube to the manifold finger tight.... Do I need to get back underthere and tighten it a lot...?3. When I changed my oil, I may have slightly overfilled it (bubbles on the dipstick).... I am going to have my oil changed in 150 or so miles.... Do I need to drain some right away, or can I let it go with no ill effect.....

[elwesso]

Also, this is more directed toward Dennis, but I did some 50-80 times.... I started at 40mph, floored it and hit the stopwatch at 50, stopped at 80..... Here are the times

5.735.945.225.67

[Q45tech]

Average 5.65, ......5.78 if we throw out the lowest. Since Darlington Field is 919 AMSL, equatable to ATL. At what temperature were the runs measured, how accurate is your finger/eye/mind coordination.

Lets call it 5.6-5.7-5.8 secs and 40F.............very good and believable for a 94 with 125k.

In 50 or so timed runs the average on my 90 was 5.3-5.4 secs at 40F WITH JWT ECU. I see as high a 5.8-6.0 seconds at 90F.

0.4 secs is maybe 35-40-45 feet depending on what part the time is measured...........2.0-2.3 car lengths.

I really enjoy even one car length on 2004 Q/M/ LS430/G35 under similiar situations because of their shifts at 63-73 mph.

Some times I wish my car smoked [blue oil] to make the run sweeter...........maybe I'll add a ATF injector to the exhaust manifold.......too fog them when and IF I pull ahead.

[elwesso]

Its approx 40*F here... My coordination is pretty good, id say above average....

The runs I did were with 89 octane, 1/4 tank of gas, and they were on country roads that were undulating.... I have flat roads when I go home, and I will calculate again....

Any help on my other things???

[911/Q45]

Spray WD40 in the area where the leak might be, the idle should change slightly and you may even see the mist being sucked in. Don't worry about the oil level being a little high. The groaning may be a bit of oil on the belts, should clear with time. If you don't hear an exhaust leak, EGR is probably OK. Tighten it at your convenience.

[elwesso]

Ok.. I never heard the WD40 trick... Ill give that a try asap tomorrow.....

So the oil level wont hurt anything, even if its causing bubbles on the dipstick.....

Would the groaning make sense if its done it the last few startups and only when starting cold???

Id really like to get these things ironed out before I go home tomorrow (fri), as i am still at the shop with all the tools....

[90Q45blue]

Is it a groaning or a whining? The only time my idler pulley on my alternator and my tensioner pulley on my power steering started sticking and went out was in cold weather. But, I would hear more of a whine then a groan.

Nick

[elwesso]

Well im not sure, its probably more of a whine..... Ill take a sound clip sometime and post it here....

[Q451990]

I still think it's the transmission at start-up. Try listening at the pan/bell housing area and see if it's loudest there. If you have a mechanic's sthesecope you can check the idler pullies too - they'll make a howl much like a bad p/s pump as well.

I like brake parts cleaner for vacuum leak testing too... leaves no greasy residue

Heath

[elwesso]

Heath.. This is much louder than anything ive ever heard..... I dont think its the transmission......

Its sounds like a REEEEEEEEEEEEEERRRRRRR and the noise fluctuates if I adjust the RPMs... It definitely sounds like its coming from right belor the oil filter....

[Q451990]

Could definately be an idler pulley then... I've heard of a few P/S pump failures, but not a lot.

This will be your best friend in locating noises like that...

http://www.harborfreight.com/c...41966

Heath

[elwesso]

Well, Im taking my car in for service this week, so I will ask the guys there if they notice anything....

I would think if it was a pump failure it would happen all the time and the PS would be different.....

I think ive located my vacuum leak somwhere around the TB... I will pull it off and see if I can locate something....

[90Q45blue]

It's probably not a pump failure. About a year ago I was getting a loud whining noise and I took it to the dealer. They told me that my power steering pump was failing, so I bought the part from a junkyard and had my mechanic put it in. Still had the whining noise. Took the car back to my mechanic and he told me I needed to have the idler pulley on the alternator replaced. When he showed me the old one, it was so stuck that it couldn't even move with force by hand or wrench. The only other time my car has made a similar noise was about 20 miles before the tensioner pulley on my power steering went out. Both of these are cheap fixes (under $50). I'd check them out yourself or have your service guys give it a look.

Good luck!

Nick

[elwesso]

Id probably DIY those.... Im sure they are easy.... Im starting to think its a tensioner pulley.... Ill be sure to have the guys take a look at it...

I simply give up on this stupid vacuum leak... Im going to take it to the dealer and see if they can find it..... I can hear it clearly, but I cant find a hose thats unplugged..... I think its coming from the rear of the plenum, more towards the drivers side... IAC hose is good, the other plenum hose near that is fine, and the brake booster hose is fine.... I took off the TB, and everything there is just fine...... Ive doused the engine in brake parts cleaner and the idle doesnt change.....

Do you think a nissan dealer would work on my car?? The closest infiniti dealership is in indy (30-45 mins away) and the nissan dealer is really close....

[PalmerWMD]

with simple issues such as those your local Nissan dealer should be fine.

Fred...

[elwesso]

Ok...... Well I will have my independent shop take a look at it first, when they do my oil change..... If they cant locate it then Ill take it to nissan...

Would they be able to hook it up to a consult??

[elwesso]

I just had a thought.... Do you think that the brackets under the plenum (underside) would make a difference? I didnt reattach some of the bolts, and I couldnt see how that would make a difference... Im just trying to brainstorm....

[DAEDALUS]

Not directly that I can figure, but if they're not bolted down, then they're shaking and rattling more than they should be. Could that damage a hose or cause one to dettach? Probably not right away, but who knows?

[elwesso]

Well it was only one bracket (near the TB) and I couldnt for the life of me get it back on...

All of the other ones are securely in place. And there is just a tiny bit of play in the big metal hoses......

Ive been searching on the internet, and ive found a VACUTEC (http://www.vacutec.com) smoke machine thing and im gonna look around for a dealer or shop that has one. Sounds like its the easiest way to find leaks, just hook the machine up to the brake booster hose (car off) it pressurized and leak is revealed!!!

Also, do you think the vacuum leak that I have (causing fast idle) is also hurting gas mileage and performance???

[maxnix]

Be very scared of "mechanics" that have "left over parts."

Think Nissan was just trying to prop up the Japanese employment figures?

[elwesso]

Brian... I did the work myself if you didnt already know.....

Well its going in on Wed. Im not driving it tomorrow because I am using straight 30 weight oil and its too cold for it to sit out all day..... Not to mention the oil light stays on for a second after startup.... This engine is on its last days.....

Im having them find the vacuum leak (they say they have a tool that can find them good), looking at the idler pulley (related to oil pressure maybe?? Dont know how those work), and evacuate and recharge the AC.... Plus an oil change...

They gave me an estimate for about $100 to do the AC... Reasonable.....? Anything else I should have done while its in there??? Im all caught up on fluids.....

[DAEDALUS]

Hopefully there's nothing wrong with the oil pressure. Idlers are cheap and easy, oil pumps aren't. What do you need done to the AC? Usually quotes for AC work are "price plus refrigerant".

[Q451990]

If the engine is on it's last legs, I wouldn't spend a dime on A/C maintenence... you'll have to evacuate the system again anyway for a motor swap. The oil light wouldn't be related to the idler pulley - it's chain driven off of the crank shaft.

Hope you didn't get agressive with cleaning agents and clog the pick-up strainer. Any oil pressure lights before switching to straight 30W?

I'd try switching back... I know you're trying to use some old stock, but oil is cheap compared to hard parts. $1 supertech oil at Wal-mart should be fine for your cleaning purposes. Save the 30W for the lawn mower next spring!

Heath

[elwesso]

No oil pressure lights before.. I dont really know if low oil pressure had anything to do with the idler pulleys, because it didnt do it before I did the plenum and switched to the heavy oil..... Ill switch back to the 10w30 and report back....

I didnt do ANY sort of cleaning while I was in there.... No ATF in the oil, NOTHING... I just think the oil was too thick for cold times......

I didnt drive the Q today (sat in the toasty garage all day).... Im taking it in today for the oil change and I have my appointment for the stuff tomorrow.... Well im leaving the car with them tonight since I wont be able to make the 1:00 appointment.....

The engine still probably has SOME life left in it..... Doesnt use any oil or doesnt smoke..... Still must be pretty strong since my 50-80 times are perfect....

I wanted to get the AC vacuumed and recharged, since it was kinda weak last summer.... We'll see how it goes and I'll do that come spring (they wouldnt up their charges).... I just thought I would do it all at one time.....

Let me know what you think.....

[911/Q45]

How did you tighten the crank pulley bolt? If it's not 270 ftlbs the oil pump drive could be slipping causing low oil pressure.

[elwesso]

I think there is a slight misconception here... I didnt replace the tensioner pulley, its getting looked at to figure out exactly what is causing this horrendous noise when i fire it up first thing.... I think i have low oil pressure (only at startup) from the heavy weight oil Ive been using to fill after the rocker covers got replaced.... Getting oil changed to 10w30....

[911/Q45]

Heavy oil would be less likely to give you an oil pressure light. The crank pulley bolt holds the slip fit oil drive gear in place behind the front cover. If it isn't torqued properly it will allow the gear to slip resulting in the oil pump not turning enough and, as a consequence, low oil pressure.

[Q451990]

He hasn't had the crank off... but you're right that could cause the problem. Wouldn't a thick oil take longer to flow and reduce oil pressure?

Heath

[911/Q45]

Bad Me!

[Q45tech]

Thicker oil/higher viscosity has the highest pressure after the system is filled by the pump..............guess you are referring to the filling time of the system.......before the pressure rises.

A thick oil will stay on the bearings longer after shut off.

Always park on a level flat don't allow gravity to partially empty the bearings.