Shifty Knob

Just doing some searching and saw his iac valve was a little different than the one I just installed. Can you help answer my question? I'm just glad someone did cause this is an old thread.

marktab

Hello -- to repeat, your question is whether the vehicle will "work" without the cap. The keyword is "necessary", and my question to you is necessary for whom. The tricky issue in auto mechanics is not having sensors (for most of the vehicle) and not even knowing what to measure and under what conditions.

You can test the car's response by seeing how it operates without a cap (and even then you have to guess about the range of operations from cold startup through high RPM extended operation). I do not know the effect of not having a cap and I doubt that most would know. On this thread I showed how to clean an EGR valve tube, though I do not believe anyone on this thread has provided complete science on what it means to run with a clogged one (my engine ran with a clogged one).

As all vehicles age, they begin to lose parts. Some parts wear out and others break. Sometimes mechanics break some parts to fix others. I recommneded altering bolts to fix the EGR tube. Unless you have an engine rebuilt with some type of limited warranty, your 4th generation Maxima is probably like most all others out there, with no warranty coverage.

It is possible to obtain a replacement assembly from a used parts dealer. Or, as you say, you could attempt to refabricate a cap (or obtain one) and perhaps need to create new holes. When people make alterations, it's important to again not break something in an attempt to fix something else. Obtaining a used unit from a scrap yard is probably the easiest and most cost effective path to take.

Shifty Knob

Thank you for taking the time to answer my question,and get my posts up. Once I get my 15 post requirement I will post a picture of what I'm talking about. I have the brass cap from the old iac valve, I was simply going to transfer it to the new one but the screw holes appear not to be tapped on the new unit.

Iilac

iTrader: (65)

Will cleaning out the tube help in reducing NOX on Smog?

marktab

Hi Iilac -- The EGR tube is just a tube, with no moving parts. This tube is connected to the Exhaust Gas Recirculation (EGR) system. And the answer is that the EGR system is intended to reduce nitrogen oxide (NOX) emissions.

Of course, we are assuming that the EGR valve and the rest of the EGR system is functioning. Any repair manual will give you a diagnostic procedure to test the EGR valve as well as the EGR system for this Maxima. Cleaning the tube is a required but not sufficient step in making the EGR system work properly.

Polar

Great write up and pics on the original thread. I won't get to mine for another month but it has 104Kmi. I'll be interested to see how much blockage she has because it's been tons of city driving. Maybe the reformulated crap they make us buy in California will keep it clean- it would be nice to have at least some benefit from this stuff!

Maxnub

Just cleaned my egr and lost the lower tube gasket. Would regular liquid gasket work for the bottom fitting? Just a small line around the outter edge and screw holes.

drwwalker

I cleaned the EGR valve and pipe still get the same code should I replace erg valve?

marktab

Hi Maxnub

Whatever you use should be equivalent to what you would use for an exhaust pipe. If you are not sure about your product, then go to a local auto parts store, and see if they have either gasket material (which you would cut to shape) or silicone gasket made for exhaust application.

I just did a bing.com search, and there are several such products on the market.

Good question though -- I do not believe anyone has asked it on this thread before. Because I still have my Maxima, in the future, I might find myself using silicone gasket material if my gasket crumbles away.

marktab

Hi drwwalker -- you mention that you cleaned the EGR valve. Also, you say that the pipe is clean.

When I cleaned my pipe, I found a lot of additional carbon where the upper end of the EGR pipe attaches (vertically upper). I cleaned that area too.

Just to make sure: after you clean, you need to issue a reset command to your car to clear the code. I got a device from eBay that reads and/or clears codes, and such devices are at many local auto parts shops too (they often allow people to use them for free). The code might clear itself, but I don't know how long that might take since I cleared mine with my code reader.

If I had not cleaned the tube, the code would have reappeared. I know the problem was fixed because the code did not return.

To answer your question: I do not know if changing the EGR valve will prevent the P0400 code from reappearing (after the codes have been cleared).

franke

I have the same one as you. They must of made 2 types mine is missing the cap also and the holes where it would of been fastened are not tapped also.

pwmaxgle

Thanks to marktab for the original post on EGR Tube cleaning!

I'm in the middle of Valve cover gasket set replacement prjoect and UIM is already off the motor.
While I'm at it, makes sense that is perfect time to tackle the EGR Tube clean
preventive maintenance project.

So I start the EGR tube clean project and I ran into an issue. Not surprised...
When I try to loosened the nut that is on the stud that is to get hacked on the lower side of the tube. The stud is turning loose with the nut instead of just the nut coming loose.
I'm guessing I may have to remove the entire stud & nut assembly for now to remove the EGR tube?
For now I just backed away from it and spent considerable amount of time reading this entire thread to gather ideas to do the job correctly without making any mistakes.

After going thru this thread, the method posted by fattony is appealing to me.
By cracking loose the main EGR pipe coming from the exhaust manifold (that is if I can crack that big old pipe loose) then move the big main pipe out of the way so I can remove the entire stud & nut assembly from the lower side of the EGR tube?

Has anyone run into same issues as I'm facing?
Would like to hear how other members resolve the issue with the lower stud & nut assembly coming loose together...
TIA!

pwmaxgle

UPDATE.

I successfully removed the EGR guide tube!
This evening after dinner break, went back in the garage and I wanted to see how far out the stud would actually come out with the nut attached to it.
So, I started to loosened the nut more and more slowly.
At first I could see the stud turning loose with the nut then after few turns the stud actually stopped turning and only the nut started to spin loose!
WTF! But that's a good sign! Felt like I got a big break on this.
I was able to loosen the lower nut down to the flange.
Then I cracked loose the upper nut, anticipating same scenario and it did the same up there also. The stud started to turn loose with the nut then after few turns the stud stopped turning and the nut came loose all the way.
I was relieved that both nuts are completely loose and both studs are in place.

So then I opted for the lower stud flange hacking method.
I have an older model dremel tool and just happen have a small cutting wheel for it. It took some doing trying to make room, getting the right angle for the dremel tool and being as careful as I can not to damage anything else around the stud. Once I got the angle on the flange, it probably took about 3 minutes or so to cut off the end of the flange.
I somehow knicked the main exhaust pipe next to the flange with that cutting wheel... I was pissed at myself for doing that... But it's not damaged, so I'll probably put some Hi-Temp paint to patch up the knicked scar to keep the are from corrosion.

My EGR Tube wasn't clogged up but still quite a bit of crud in there, so I look forward to cleaning out the tube and the lower port hole from the EGR Valve assembly attached to the engine. Then when I get done replacing my VC gasket set I'll clean out the UIM and upper EGR tube port.

Thanks again for sharing this valuable EGR Tube cleaning project resource!

marktab

Thanks PWAngle

Glad you solved the stud turning issue

Of course the real issue is that all cars of this generation Maxima are getting older and older. It does help to clean that stud off (once that pipe is removed) with something like a wire brush (to remove mostly oxidation). Functionally, the nuts only need to be snug, so I don't see an issue in putting something like regular grease on the nuts before replacing. That way, the nuts could come off in the future without further spinning off the studs (which of course could themselves be tightened before replacement -- and if they are already loose, then something like Loctite applied between stud and engine and allowed to fully dry before replacing). So in summary, stud to engine should be tightly bonded, but nut to stud should be comparatively looser.

Your job is more than maybe most who do this maintenance. But as you can see from the crud especially at the top, it's way dirtier than a typically cleaner intake area would suggest. I think you could also use that Dremel with a brush attachment to get a lot of it cleaned off and quickly too. I have a Dremel, but I found that a small tip screwdriver was sufficient for much of it. Regular wire brush is good too.

I believe that people can keep these engines going a long time with proper tune-up and oil changes.

pwmaxgle

Thanks, marktab!
Yeah I'll apply Permatex anti-seize lube on those lower studs before re-installing nuts. I always apply anti-seize on bolt threads where it's needed for scheduled maintenance.
For now, I don't think I need to do anything to those studs like applying locktite as those studs are still threaded in the engine side, so I'll just re-install nuts back on when I'm ready to re-install the tube and call it good.

Yep, I'll be cleaning the hell outta that tube and the lower port hole on the engine side this afternoon with what ever tool and chemicals I have in the garage!

Definitely hoping I can drive my 95 GLE with 113K miles for many many more years/miles with proper scheduled maintenances.

gatorsteeler

Marktab- Excellent job my man! Followed your steps to a "T" with no probs. The only thing I did differently was use a Dremel drill with a cutting disk about 2" in diameter and BARELY had enough clearance between the pipes down there but....beat the hell out of hand hacking. That EGR tube was LOADED with shizz from top to bottom. Used a wire hanger and carb cleaner to jimmy it through (well most of it anyway) and reattached. Unplugged battery cables for about an hour thinking my codes would be reset..Nope still there, its only been a day so it still might go away by itself, but buying ecu reader anyway to reset. GREAT WORK on your write-up!!!

marktab

Hi GatorSteeler -- thanks for the feedback, and your story of a successful clean. I like the word "shizz" -- JRR Tolkein was known for making up new words and more.

To answer some issues:
1) On resetting the code -- many auto parts stores will freely lend their code reader for use in their parking lot, and a typical reader will also have a "reset code" button on it. I have a code reader which I acquired on eBay, though happy to report I rarely have to use it at all for the Maxima.
2) On the Dremel -- I believe I commented earlier on this thread that I have a Dremel tool, and it was an option available to me. More important than having the tool is having practice, and it's always possible to practice first on another bolt unrelated to the car to see if this type of solution works. Some people have used powered tools, and have caused damage to other areas. The spacing is snug but not tight, so it is possible to snake a powered tool into the right location. More important, is having experience first in cutting the bolt.

At the time I posted this thread I did not see a lot of instructions using digital cameras. I have a new favorite show on satellite/cable called American Restorations, and on several episodes they mentioned using digital cameras when dissembling complex machines. Having a lot of pictures helps, especially when there is no assembly manual any more, or (as in this thread's case) when even the factory manual does not provide clear instruction.

By the way, we are not far from taking inexpensive 3-D images of surfaces. The Microsoft Kinect is a likely device. Operationally, the idea would require a visualizer for the website.

NHMAX603

iTrader: (1)

looks like this is my plan this weeked great write up ty
p0400 is a pita

gatorsteeler

update- went to Advanced cuz Autozone doesn't clear codes, only takes readings, at least around my city. Advanced just gave me the reader and said have at it! Cleared them off and drove 25 mi back home. No codes have returned.

ttrebing

Great walk-through. It took me about 4-5 hours to do the job on my 1995 Maxima SE. I used a sawz-all to hack the bolt with no issues. Used a paper clip to clear the passage from the EGR tube to the intake plenum.

Pre-cleaning, it wouldn't pass AZ emissions on NOX (2.07 with 2.00 the max allowable). Post-cleaning, it sailed through emissions with a NOX reading of .71.

Thanks again for the detailed post!

Carson56

Great post and photos. Well done. I don't think I could have done this without the detail. I just completed finished removing and cleaning this tube. It was completely blocked. My only problem is now my car is idling weird. When slowing down my rpms drop and it almost stalls. Anyone have any suggestions or experience this same issue. No idling
problems when I started this
project. Thanks

marktab

Hi Carson56 -- Thanks for the feedback.

A number of disconnections happen during this process. I would recommend reviewing your work and making sure any and all disconnected vacuum and electrical connections are reconnected. Sometimes these disconnections accidentally happen when your arms are moving around, so make sure you look all around even in areas which were not discussed for this procedure. Reviewing the work requires using a portable light and putting your body in a number of positions to see what happened. A mirror may help too (to look around corners where your head cannot be).

If you are really stumped then it would be cost-effective to have an experienced tune-up shop take a look at your work too (making sure something was not either inadvertently disconnected or damaged during the repair). A regular tune-up shop will have ways to externally test the vacuum and electrical systems to help narrow down potential causes.

thegodson1

iTrader: (1)

Got the 0302...gotta clean out my egr tubing today, man this seems like its gonna be hard, any useful tips? Anyway I can clean the egr without actually having to hacksaw? don't wanna buy a saw just for this job, I mean how do the dealers do it? I doubt they saw the bolt off..any help appreciated Im a noob on fixing things but with the right directions from here I can do it, as I've done, the ks, and egrc solenoid valve replacement. so not a total noob..just good with directions haha.

khalnayak

Thanks for the writeup.

NHMAX603

iTrader: (1)

ok soo i have my entire car ripped apart the uppper egr tube is blocked solid i cant get the lowe off its soo rusted on there haaaallllpppp

infinimax96

just clean the top. I couldn't get my EGR all the way off either. Cleaning the top and scraping the crap out from the top still helped a lot.

NHMAX603

iTrader: (1)

i cleaned the opening inside the manifold it was level with the inside of the manifold but i couldnt get to the tube my throttle body was black my car is idling at 1.5 now hmmmmmmmm everything is plugged in idk

marktab

NHMAX603: there are a number of disconnections involved, and it is easy to miss a connection. In any case, not removing the tube is a serious compromise because, from experience, the black carbon is deep in the tube and only came out through my persistent scraping.

Too bad the bottom nuts did not come off. Perhaps talk to another experienced mechanic (anyone who has seen rusty problems), and see if you can get a second pair of eyes or other tips. It would have been good for Nissan to call this cleaning regular maintenance so that you would have been greasing that bolt (and nut) and preventing the rust.

pflicht

iTrader: (2)

looks like a fun job for me tomorrow lol

Trini Boom

iTrader: (5)

I did this job last week and let me tell you, it sucks. Removed mine becaose of the P0400 code but tube was clear at top and at bottom. There was oil sitting in the EGR valve though probably due to spraying with TB cleaner from the top a while back.

I ordered a new EGR valve because the threads melted (original EGR) which I had to get the EGR pipe as well. Dealer hasn't gotten the EGR pipe yet but those nuts will be replaced as the 12mm was starting to slip due to rust decreasing the size.

asnorton44

Nice info

NHMAX603

iTrader: (1)

well the thing is ive only had then car since april never thought id hafta remove the egr tube till now and living in New England everything rusts i did spray with wd40 ...im gonna try again this weekend and keep soaking with wd im also gonna wire brush it i need this cleaned

shortdogg

Good Pictures and Directions!! Very helpful and Useful!

LoKeyM4A3

I've been putting this job off for almost a year now. I tackled this today with ease after reading this thread a few times. The most difficult task was hacking the stud which took about 10 mins and a few bloody knuckles. Unfortunately I had other major issues and now a seized engine so I cant chime in on positive or negative results of cleaning the egr tube.

shortdogg

just wanna say thanks to to the person that took these pics and directions. do you have any other projects like this?

Rocky Rococco

I've done this on two maxima's now and this instruction is quite helpful. Even if one chooses not to hack, as I did - its still a good "heads up" to indicate a difficult situation. Thumbs Up !

Buck96

iTrader: (2)

I did this "repair" as a maintenance precaution for my 96 max. It was throwing a 1005 code and i figured if I was working on the egr system I would clean the tube. With 186K miles it hadn't ever been done and it was hell to do.

I have to say this is one PITA "simple" cleaning. It took over 8 hours and hacking that bolt from above was a beast. Not saying the results aren't noticeable, especially at idle but this is not something I recommend doing more then once. If you see your codes for an egr tube coming back, sell your max for a 5 or 5.5 gen quickly! just my .02¢

marktab

Hi ShortDogg

To answer your question: no I have not posted pictures like this on any other topic. How long have you had your Maxima 4GEN? Also, what topics are you interested in?

I still have my Maxima -- which survived a hit-and-run from November 2011 -- though I got my rear and front bumper replaced. Also, over time, I have made some of my own upgrades to the car, which I could talk about on another thread if you are interested.

marktab

Buck96: sorry this procedure took 8 hours. I believe my whole procedure was done in a few hours, and that time included taking pictures. Perhaps you have to factor in the general condition of the engine. In my case, I used a piece of plywood to put my body horizontal to the engine (I did the procedure from the top, though some on this thread have been successful from the bottom).

Knowing the best kinesthetic position for the body is perhaps a subject which comes from experience -- though I know most of my knowledge in body position comes from athetic training and learning dance. An awkward body position can make a task take much longer than it should, because our bodies are optimized for motion in certain directions.

I'm not quite ready to give up my Maxima. At present (January 2012) it has about 136K miles -- comparatively to many people, I do not drive a lot. Though I do periodically take road trips, and I like to have my vehicle in good operating condition. Recently, maintenance on my car included changing the power steering rack and fixing a leak in an oil seal. I suppose some people would consider those types of fixes to be enough, and time to upgrade -- though my vehicle is still in good physical shape given the age. I suppose I may be doing this EGR tube cleaning once I get to about 150K miles, perhaps in about a year or two.

CodyCMT

I did the egr cleaning and the iacv i also took the upper manifold off. Well needless to say the egr tubes and the upper manifold were completely clogged. Once i put it all back together I cant get the vehicle to start. Maybe vacuum line off somewhere? It turns over and acts like its almost gonna start but never does. Any help would be great. Thanks