My Q45 updates...

[Justin88na]

Ok, so about 3 months ago I bought my first Q45 and I have loved it ever since! Even though when I got her she wasn't in the best condition, I knew it wasnt going to cost all the much to fix her. I have pretty good knowledge base and a bunch of experience so I wasn't afraid of the costs involved since I would only be paying for the parts and I have become very good a finding cheap parts.

When i first got her she was idling really rough and i knew there were some quick fixes to take care of the problems. I performed an oil change with motor flush, gave her some Chevron Techron to fix the injectors, and put my Z wheels/tires on because the original ones were gone(inside front wheels where worn to the wire mesh). Then I cleaned the MAF and connection. On top of this I installed my Z's K&N because the Q's filter was nasty and the Z is just collecting snow right now.

I noticed a big increase in smoothness and the grip from the upgraded wheels/tires made a huge difference in all handling aspects. Great! Now off to clean her up. Gave her a thorough cleaning and spent 2 hrs getting all the pine sap off her exterior. Now she was was getting up to par.

Took my first road trip with her on thanksgiving all the way to New York city. It cruised on the highway very well but was still giving me slight hesitation and unevenness at light throttle, especially going up very gradual hills.

So figuring it was the IACV and dirty injectors, I seam foamed the engine, took the Idle air control valve out, cleaned it and reinstalled it. Also, I changed the oil again(what a b**** it is to get that filter loose!)

After that, I installed a new fuel filter and fixed/removed the aftermarket security system that was making my interior lights flash for 60 sec when opened or closed the doors. Great! Things are getting better!

Unfortunately it did not get rid of my engine issues completely, however it did help a lot. Instead of at idle and shaking like it has highly aggressive cams, it just mildly vibrates. Back to the drawing board.....

So this weekend I was able to OHM everything and the results are in!I need one injector completely, it had no resistance at all and two are starting to go, giving me 23 ohms. All the rest of them were at 14 ohms. On top of this I checked the knock sensors and both were in the 250-280 range. Which means I'll need a new set of those as well. So at least I know exactly what is wrong with the car now. So this coming month I will be getting some(4) used injectors, get them professionally cleaned. Order some knock sensors and also order all of the hoses that are under the intake manifold. I figured I would replace those while I had the intake off.

So that about covers the mechanicals. Now to the suspension/brakes and wheels.

Like I said the original wheels that came with the car were highly worn on the insides, so I looked into the issue yesterday and it seems my tension rod bushings are shot and making my new wheels/tires wear extremely fast as well. So I will be upgrading them shortly to urethane Z32 bushings and getting new tires for the fronts.

On top of this the brakes needed replacement so I replaced them with new rotors and Axxis Metal Master Pads. I highly suggest these on any car. I have had them on my 5 series and my Z and have been nothing but happy. Low dust, great bite and awesome modulation.

Well, thats all for now. Take care and hope this gives you guys some motivation to work on your G50's!!!

[qship96]

Worn tension rod bushing are not the cause of rapid tire wear! More likely the toe is way out of spec. check upper links for camber wear issues also while you are getting a professional 4 wheel alignment performed.

[maxnix]

Well, thats all for now. Take care and hope this gives you guys some motivation to work on your G50's!!!

While your gumption is to be admired, your post reminds me of the value of reading the previoius posts on here!

[jak89]

How did you get the pine sap off? I just got a 240 thats covered in that stuff.

[Justin88na]

I used simple green mutlipurpose spray and a terry towel and my fingernails. You can also use WD40. I let the Simple Green soak a little bit into the sap before rubbing it off. It took a while, but believe me, the car doesnt look like its covered in boogers anymore.

Do NOT use Goo Gone, it will eat into the paint.

[Justin88na]

Worn tension rod bushing are not the cause of rapid tire wear! More likely the toe is way out of spec. check upper links for camber wear issues also while you are getting a professional 4 wheel alignment performed.

Yes they are! When the bushings in your tension rods go, or if you remove the tension rods completely, it drops the front end. My Z31 currently doesnt have any tension rods installed(gotta remove the stubborn control arm to install the new ones) and the front is dropped 2" lower than the back, creating negative camber and making tires wear out on the insides. Therefore the worn/ripped bushings on my Q45 are causing the front end to drop(you can visibly see) and therefore causing the negative camber and worn inner tires.

[qship96]

Yes they are! When the bushings in your tension rods go, or if you remove the tension rods completely, it drops the front end. My Z31 currently doesnt have any tension rods installed(gotta remove the stubborn control arm to install the new ones) and the front is dropped 2" lower than the back, creating negative camber and making tires wear out on the insides. Therefore the worn/ripped bushings on my Q45 are causing the front end to drop(you can visibly see) and therefore causing the negative camber and worn inner tires.

UUUGGGHHHH OK.........too much wrong here to even comment

[Justin88na]

UUUGGGHHHH OK.........too much wrong here to even comment

Whats wrong here? I never said the Z was on the road :P

[Justin88na]

Well, I just replaced my injectors, rails and knock sensors. Wow, was that a pain in the a**! Also, i replaced any misc hoses I broke or snipped in the process(had to fab up a brake booster hose and misc vac/fuel lines). On top of this I cleaned the interior of the intake manifold and lower intake manifolds.

All I have to say is DAMN! The car is running great right now. I have to figure out why it goes up to 2k and revs down to 1k when I put it into park but thats about it!

[gonzo09876]

My Q45 I just got from a family member was hesitating at slow idle. I was going to replace the EGR valve but I didnt know If that would fix it. Thanks for posting such a detailed message did replacing the injectors work.I have gone thru it and Found, Hesitation at slow idle,The TCS light will not go off? How is that fixed?D.H

[Justin88na]

I dont have TCS, however, my car was idling rough and the hesitation was the worst going up hills. It would basically have to chug up the hill or I would need to floor it to get the fuel pressure up and allow the other cylinders to carry the weight of the dead cylinder(the one with the bad injector).

I dont know if the EGR would fix your issue. I would Ohm the injectors and knock sensors before you do anything. It is quick and easy and if you dont have an Ohm reader, ask any of your buddies that are musicians(think guitars and basses) or electronic nuts. It wouldn't be bad to own one though.

As far as current performance, the car runs great! I had to replace the vac hose going to the FPR, and I cut it too long and its binding, so when I let off the gas it gives a slight buck, but thats an easy fix.

Good luck!

[Q45tech]

Bring the Q45 to T3 S. Cobb for a complete diagnostic:list of defects, ohm injectors, ks, Consult test and report for ~ $90>$170 you can know not guess.

Lately [since Mar 2008] the first problem always seems to be injectors. So our 15 years of historical data costs need to be updated by about $1400 to reflect 4 injectors [on average] and plenum work.

We use to say most early Q needed $3,000 now it might be $4400 obviously ~1/2 if you do it yourself [correctly].

Many times it is worth buying a few Q45 junkers just to bolster your personal spare parts inventory.

EGR valve rarely gets plugged the problem is always the port/passage into plenum. Remember EGR only works at steady rpm cruise not at idle or acceleration so obviously it cannot affect idle!!!!

Coils and harnesses are very old and brittle by now so after replacing all spark plugs............reexamine them after 1,000 miles to find ocassional misfires that WILL NOT SHOW up on codes.

Plastic chain guides on 90-93 always must be replaced FIRST before wasting money on non destructive items.

[Unnatural1]

EGR valve rarely gets plugged the problem is always the port/passage into plenum. Remember EGR only works at steady rpm cruise not at idle or acceleration so obviously it cannot affect idle!!!!

How about an EGR that's stuck open? That will affect idle. Admittedly, the chances are slim but in general it's not bad to rule out things like that.

On another note, Justin, it's worth spending the money on diagnosis at minimum. You will save yourself money in the end by avoiding replacing parts that are not at fault. Commonly known as the "shotgun fix!"
Modified by Unnatural1 at 11:52 PM 3/28/2010

[Q45tech]

How would an EGR stick open? Anyway that's a primary test by pushing up on diaphram with finger to see if idle stumbles [no stumble clogged or reduced flow in system].

[Justin88na]

Well, I've checked the upper control arms and they look fine. However, the tension rod bushings are shot and are leaking/melting away. Does anyone know the ID of the bushings? I have my poly Z31's and I know that the tension rods are interchangeable between the Z32, however thats with adjustable rods, and the bushings dont come into play.

I really dont feel like pulling my rods figuring out that my Z31's are not the right size and then putting the Q back together with toasted bushings.

Ehh, I just might order the Z32 bushings and stop worrying about it.

On other news, I bent my hood this weekend trying to get everything hooked back up

Yeah, so I have been having an issue with this for a week, I got one hinge totally(LH) on, the other(RH), I have one bolt on, the other was stripped trying to put it all back together. Then I got the hood strut on the RH on, had to take my gf to work, so I went to shut the hood slowly, and the hood creased where the one strut was installed.

I bent it back really fast, with my hands, but it isnt perfect..... Oye....

Well I am starting to think I shouldn't put the VH45DE in my Z, and just put the TT trans in my Q. Figured it would give me less down time and more fun time! Either way, I need to get my gf's SER Spec V back on the road first.

[Unnatural1]

That's a good question, but I've seen it happen. My guess was heavy carbon build up. Not an Infiniti but just making the point.

[gonzo09876]

Thanks for your input, I will have a test run on it by a mechanic.