New member...restoring 1994 Q45 to pristine...need advice from masters...

[Dabizzo1]

I'm here in New Orleans, LA and after selling both of my cars to fix my house post Katrina , I ended up getting my wife a 4runner for daily driving in the WORST STREETS IN THE USA>>>WOOHOO, and I finally decided to get my hands on one of the cars I've lusted after since I first saw one. After reading these forums for the last 4 months, I did my homework and found an aesthetically aok 1994 Q45 (base model w/ BBS wheels) in Midnight blue pearl from a golfing doctor who traded it in to PARK PLACE Infiniti in Dallas, TX. I bought it after it went to auction and I'm in the process of bringing it back to an mechanical and aesthetic pristine state. The car simply needs new brake pads (OEM only), new shocks (Tokico blues on the way), and the car threw a CEL with a rough idle and here is what I've done to address it so far:

--New NGK plugs...oem from Ray brandt Infiniti--New OEM fuel pump (started humming and I replaced it the next day...FPCU aok---no scorch marks)--Injectors 1,2,5,7,8 replaced with OEM at Ray Brandt Infiniti--New PCV with all hoses under the plenum that needed it replaced.--New MAF---thx POPPOP---New hood struts---New radiator fan...old one was stress cracked--IAC cleaned throughly and tested....actuated under 12v load..new gasket--New knock sensors and harnesses--all harnesses inspected and reinstalled with anticorrosion gel--throttle body degunked thoroughly...was pretty nasty--ALL synthetic fluids(transmission flush and fuel rail flush).--New 760CC-amp battery from Autozone (can't find a red top here)I have 2 new oem O2 sensors from Scottsdale Infiniti (got most of my parts there), but the dealer here said my O2 sensors are aok...I figured with 99K on the car, I'd replace them as a preventive measure, so I still have the original O2 sensors on the car. The CEL went away after the KS and FI were replaced, but I still notice a wobble at idle after warming(with an intermittent exhaust sputter as well), whether in park or in drive. I have not taken the plenum off myself to clean it yet, so it still may be dirty inside. There is NO hesitation under load (hauls arse), only the wobble under idle. My first instinct is that one of the O2 sensors may be gunked or on its way out, but wouldn't a CEL get thrown? Any advice would rock. Also, I must say this....there are some sequentially thinking brilliant problem solvers on this forum...Q45Tech, Maxnix, and Elwesso rock...I'm a senior in ME here and the diagnoses I've read on some posted problems are dead on...I tip my hat off to you. The Saints are gonna play today vs Philly so since I work in the FQ (I manage K-Paul's and it should be a madhouse), I'll try to repost on Sunday after I do some more cleaning under the hood. Thanks for this forum....best tool for a Q owner......GO MF SAINTS!!!!!!!!!!!!!

Boris Palacios



Modified by Dabizzo1 at 2:11 AM 1/13/2007

Modified by Dabizzo1 at 2:31 AM 1/13/2007
Modified by Dabizzo1 at 2:32 AM 1/13/2007

[elwesso]

Welcome to NICO Dabizzo..

Man this is so refreshing to have someone post up who's already done their research and knows mostly what theyre talking about..... Id love to see this Q, the blue is one of my all time favorite colors, its so hard to find!!!!!

the o2 sensors will have no impact on how the car idles or performs honestly. They really only effect fuel economy.... Under hard acceleration or if the ECU sees bad o2 sensors, it tries to maintain a 14.7:1 AF ratio..... since thats the stoichiometric ratio. When youre cruising it tries to maintain 15.x:1 or so (leaner)..... WHY YOU CAN GET MORE HP with upgraded ECU! as o2 sensors age they dont react as fast, however o2 sensors cannot effect fuel mileage more than 15-20% worst case.... Theyre easy enough to replace that its not a real issue...

If you want the easiest way to tell whats causing your bad idle.... You can start with ohm testing your injectors...http://www.q45.org/ohminjectors.html .. If you're an engineer i know you never leave home without your digital multimeter!! I never leave home without mine.. If the injectors turn out to be good, then go to the dealer and get a POWER BALANCE TEST done.... Be sure they print out the results and you can post them here...

[ceningolmo]

Way to go brother-man! Check my thread in this forum...

zerothread/212964

LOTS of pictures and info regarding stuff under the plenum (KS, injectors, hoses, harnesses, plugs, etc). Might be handy if you need some help locating things.

Good luck... I hope all goes well for you. We'll be here to help when you need it.

[maxnix]

Man this is so refreshing to have someone post up who's already done their research and knows mostly what theyre talking about........

Many of the new members don't realize what they are missing in the original discussions. It is human nature for repetitions to omit the fine detail of the original discussion. There is a lot more knowledge there than how low can I go on dubs.

I think most of your problems can be traced to the need to clean your plenum, IAC and EGR valves. How you got into the knock sensors without replacing all the hoses and doing the cleaning is....well, curious.

Anyway, everything I know is due to Dennis and a few other members of this board, few of whom are still here form the earlier incarnations like Heath still is.

[Dabizzo1]

Hey guys, thanks for the warm welcome and replies...first things first.....THE #$%@$#% SAINTS WON!!!!!! The French Quarter was a madhouse tonight! Woohoo!!

Anyhow, I also suspectged the EGR system could be gunked up as well MAXNIX. Could that affect the idle? Also, how do I go about removing the EGR valve for cleaning? Also, will the EGR throw a CEL (intermittent when hot) if bad....possibly faulty solenoid? My EGR is probably gunked given the dirty emmisions emitted due to a progressively choked engine before I got it. When replacing the pcv, I noticed how dirty the old valve was and I remember reading on this forum how air could actually flow backwards...unreal. Also there was a little bit of oil condensation as well in the TB, the plenum, and on the pcv. Q45TECH stated in a post that one of the advantages of synthetic oil is that it minimizes this condensation(assumedly due to its thermodynamic properties or advantages across the temp/pressure state curve....temperature and pressure ratios affect EVERYTHING in any system, especially in a pressure-flow system such as an auto air intake). Apparently previous owner liked to golf too much to do scheduled maintenance on time. Thansk again for the input. I'm glad to be a part of this forum now, and Ceningolmo, you are a madman to document yout plenum job so well...you rock ...I'm the one who tells my wife whenever we go anywhere, "yeah, I'll bring the camera and take PLENTY of pics", when at the end of the night, I took 1 or 2. Much less when I'm under the hood of a car. I just crank Nine Inch Nails in the garage and IGNORE EVERYONE. You are a patient man. I'll repost soon. Boris P.
Modified by Dabizzo1 at 10:25 AM 1/14/2007

[elwesso]

the EGR wont really effect how it idles, however it needs to be cleaned.... It sounds like your idle problem is somewhat intemittant.... Wonder if it could be a MAF connector or something?

[maxnix]

IAC valve operation affects idle.

But to reach your goal, you will have to clean them all the old fashion way.

[redmanfx]

the EGR wont really effect how it idles, however it needs to be cleaned.... It sounds like your idle problem is somewhat intemittant.... Wonder if it could be a MAF connector or something?

I disagree with the EGR not effecting idle. When my EGR system was cleaned(it was very dirty) my idle was even smoother then it was previous to the cleaning and the car did run noticeably much better and quite. I did have quite a few things done at the time so I'm sure it did help that other things were changed and cleaned as well.

[Q451990]

I did have quite a few things done at the time so I'm sure it did help that other things were changed and cleaned as well.

The EGR is closed at idle, so I'm sure it was the other stuff. Either way, it's a good thing to clean pretty much everything under the hood! A clogged EGR will make detonation more likely in hot weather since it helps slow combustion slightly. I also noticed once that a bad or disconnected EGR can result in a slight "clunk" in the differential at low speed stops - but I have no idea why...

Heath

[ceningolmo]

Excuse me for being retarded... but, can someone give me some procedure for EGR cleaning? Which parts, which cleaners, how long to clean, how hard to do?

[elwesso]

I used various things to scrape the EGR, however paint thinner removed most of it.

[ceningolmo]

Ok... explain it like I am 6 years old. The EGR... i know where I bolted on the EGR gasket. Do the bolts actually go through the EGR, or is the EGR actually the saucer shaped thing just above it connected via vacuum hose?

[elwesso]

That is the EGR valve (saucer)... That normally doesnt concern us, it is the pathway that goes from the EGR valve to the plenum. EGR is actually the name of a system, comprised of the EGR valve, the EGR-C solenoid (basicallly lets the ECU control the saucer)..

Post edited, ehres a crash course on EGR... Click the image to enlarge

[Dabizzo1]

Holy cow my EGR inlet was carboned to death...the EGR sensor tip was covered in carbon as well. I cleaned, or rather scraped the plenum inlet with a small screwdriver head and got all of the crusty crud out onto a rag. I used throttle body cleaner and a small rag on the egr valve innards itself. The tube is aok, but to be thorough, I won't be able to get into the 90 degree bend within the plenum (As a previous post mentioned) inlet to decarbonize until I remove the intake and pull the TB off...I'll do it sometime this week. What I did tonight helped the idle a bit. I jumped on the interstate and as usual...hauls arse. Intermittent CEL is gone....I suspect the gunk on the EGR temp sensor was setting the CEL off when restarted after the car was warmed up. I was working in the garage while watching Chicago beat Seattle....Saints are gonna freeze there arses off in Chi-town...thanks again for all the input fellas. Wes, you da man, and thanks for da pic! I'll keep you posted. Boris P.

Modified by Dabizzo1 at 6:46 PM 1/14/2007
Modified by Dabizzo1 at 7:04 PM 1/14/2007

[Dabizzo1]

Hey guys...just had an epiphany of sorts. The car vibrates at idle as I mentioned ( I can feel it in my seat) but the motor has no shimmy now at all....rpm's do not move at all. The motor has no deflection upon acceleration, so motor mounts are ok. However, the shimmy at idle is amplified when in drive or reverse (like a rotational wobble under my seat). Could it be my transmission mounts are shot? I know I've been dealing with a gunked motor but the motor is breathing like a champ now. I feel no shimmy at speed but only at idle. Also, I picked up some ISO-Heet for my next few tankfuls as well. Racking my brain on this one... Boris P.

[elwesso]

check your injectors first!

[maxnix]

And MAF connector. Neither have you mentioned your IAC valve.

[Q45tech]

Make a mini roto rooter from a length of old throttle cable [or something similar] and drive with a drill..............saves hours.........soak first in various solvents.

Make sure the pipe to exhaust is clean.

Since at steady cruise EGR gases [Nitrogen and CO2+ water vapor] may make up >10% of the air volume going into engine.............where the fuel savings from EGR comes into being.

The Q EGR is old fashisoned in that it is very similar to that in use for 38 years on domestic engines. So no excuse for not understanding it fully.

[Dabizzo1]

Hey all, in reference to the recent posts, this is what was already done to address the process of degunking my motor.

The IAC was the first thing cleaned with TB cleaner. The solenoid was separated and the mechanical shaft moves freely. It was pretty dirty when I took it off. A new gasket was used upon reinstallation and the adjustment screw was set to 2.5 turns from bottom. The engine idle is now constant with no engine quiver.

The injectors were ohmed at the dealer when they had it 2 weeks ago and the out of spec ones were replaced (1,2,5,7,8). KC sensors and their harnesses were replaced as well by them. I was told by their tech that apparently the car already had most of its underplenum lines redone, so none needed replacing. I plan on reassessing that when I get to pulling it off myself for cleaning.

The maf was cleaned and tested alongside another maf I got from POPPOP. No difference. Also, the connector is intact without any corrosion or cracking. I reinstalled it with anticorrosion gel. It clicks in place with a commanding snap.

The egr is now clean as a whistle as of last night as are its passages. The ony spot I need to address is the 90 degree bend within the plenum itself. I'll do that this week. I removed a lot of carbon.

The reason I started to suspect a physically deteriorated mount is that it is quite possible that idle speed when warmed for the car can create enought harmonic vibration to cause a failed rear abosrber to deflect, causing a wobble. At speed or under throttle. the very torque of the drivetrain may keep it it place. I also scoured the forums as usual and found numerous posts concerning under the seat vibrations caused by a failed mount (rear damper) as the FSM calls it. One guy (AV8TR) found it completely cured everything upon replacement. I won't know until I get under the car and inspect it for cracking. The car is 13 years old and Lord only knows the driving habits of its previous owner (potential leadfoot). I'll let you guys know what I find. Boris P.

[ceningolmo]

The reason I started to suspect a physically deteriorated mount is that it is quite possible that idle speed when warmed for the car can create enought harmonic vibration to cause a failed rear abosrber to deflect, causing a wobble. At speed or under throttle. the very torque of the drivetrain may keep it it place. I also scoured the forums as usual and found numerous posts concerning under the seat vibrations caused by a failed mount (rear damper) as the FSM calls it. One guy (AV8TR) found it completely cured everything upon replacement. I won't know until I get under the car and inspect it for cracking. The car is 13 years old and Lord only knows the driving habits of its previous owner (potential leadfoot). I'll let you guys know what I find. Boris P.

I don't think anyone is suggesting that the rear engine mount (read transmission mount for most uses in the Q forum) hasn't gone bad. In fact, it's likely. That is a common fail point on the Q. I think they just wanted to make sure you had checked all your other likely suspects first.

Sounds like you've made great progress on cleaning up the engine...keep up the good work. You'll be rewarded.

[maxnix]

The egr is now clean as a whistle as of last night as are its passages. The ony spot I need to address is the 90 degree bend within the plenum itself. I'll do that this week. I removed a lot of carbon.

When you get the plenum off and look at the EGR inlet at the rear of the plenum, you will find more carbon to clean out.

[Dabizzo1]

Oh without a doubt Maxnix. I could see a ring of carbon on the lip of the EGR inlet right behind the throttle body with the butterfly open. Plan on using part of my gun cleaning kit on it when I pull the plenum off. I would have never been able to arrive at the point of realization with regards to troubleshooting overall without this forum. You guys truly rock. What makes this forum so cool is that for the most part, no one is worried about slapping a fin on their car or trying to put the largest dubs on their car. The common thread here is that mechanical correctness prevails...virtually all who post here want to accomplish their goal correctly, without half-arsing. I really dig it, especially with such a car that no one knows is a sleeper. And for me specifically, my wife thinks the car is "really pretty" and can't wait till its done, so I get no lip for tinkering, which is my addiction and therapy at the same time....the process for me is the fun part...I'm a big GEEK! I'll keep you guys posted with my quest for wobble free idle. Oh yeah, I also am feeling a slight vibration in 1st gear in my driveline from the rear of the car under throttle as I take off from a stop...could be attributed to the driveshaft angle being off due to toasted mounts affecting its bushing.....pure theoretical conjecture on my part but inspection will either confirm or punk my suspicion. Thanks again. Boris P.

[ponzy]

good job man, i'll be doing mine this wkend.

[maxnix]

What makes this forum so cool is that for the most part, no one is worried about slapping a fin on their car or trying to put the largest dubs on their car.

You obviously haven't been hanging around the Q45 Forum. It's all cosmetics and vroom-vroom exhausts and caster wheels with ridiculous offsets and cheap rubber bands for tires. A bunch of driveway queens being made from castrated Qs.

The urge to restore and conserve is inversely correlated to the age of the owner. Few of the young noobs will ever know what a proper performing Q45 is like.

[Black stallion]

Finally, someone in my neck of the woods who appreciates the sleeping Q and is not taking a beautiful luxury sedan and country-fying it.

Welcome to NICO I have a few local contacts here locally that will really help in your Q restoration. I also notice you have a lot of your work done at Ray Brandt. Are they any good? It would be a quick drive from Baton Rogue (in the Q!). I don't let my tires roll on the parking lot of the dealer here.

Anyway I pray you are having much success getting things back together after the storm. If you need parts for cheap or just want to compare notes give me a shout [email protected]

WHO DAT!

[Black stallion]

I know what you mean Brian. I look at some of them and shake my head. It's like they have tons of money and no taste whtsoever. I was fortunate to have experienced my first Q in '91 at the ripe old age of 16 (yes, someone let a 16 yo test they're 1 yo $50K luxury car!) Long story short, after falling in love that day I finally got my own 9 yrs later and will probably always own a Q.

[maxnix]

I was fortunate to have experienced my first Q in '91 at the ripe old age of 16 (yes, someone let a 16 yo test they're 1 yo $50K luxury car!) Long story short, after falling in love that day I finally got my own 9 yrs later and will probably always own a Q.

Lucky you. I was much older, although I did ride in my wife's uncle's 1991.

[kdkrone]

What does CEL stand for? I think I will make glossary for this forum.

Ken

[96Qowner]

Check Engine Light

[maxnix]

I think I will make glossary for this forum.

There is one floating around somewhere on this Forum.