chillin014

iTrader: (67)

I didnt expect to fail emissions when i went to get my inspection but i was through the roof on the NOX%. I mentioned that i had a code for EGR valve and the mechanic said then that would be the reason. I can't remember if i had the egr code when i got my inspection last year (but i've had the code for a long time).
So does this sound correct? i fail emissions horribly in only this ONE part of it (the NOX) the c02 and everything else was fine. i have 15 days to get this fixed and the egr system looks like a big f*ing mess.
is this something worth cleaning? cause i can't afford to fail it again and then pay to go back a 3rd time.
Dealership wanted 160 for the egr valve, and the auto store wanted 100.
any advice or anything ...throw it out there. cause this egr crap has me p.o.'d

f550maranello2

iTrader: (2)

honestly its probably not the egr valve.. they rarely fail.. check the tube from the egr leading into the upper intake manifold... its probably solid.. and check for the egr solenoid as well.. ihave the same problems..

chillin014

iTrader: (67)

yeah the haynes manual has a real vague explanation of how to test it. you mean solid like caked with crap?
i cant find my emissions sheet from last time i got my inspection. but this is my results for this time.
standard for NOX is 937 at 15 mph my car read 2767
the standard at 25 mph is 848, and my car read 1961
my dilution was in the 14's and co% passed very well and so did the HC.

chillin014

iTrader: (67)

i have a budget y pipe but i passed with it last time...so i dont see why that would be the problem. plus i was told that the y pipe only mattered when you were warming up your car.

f550maranello2

iTrader: (2)

wow thank god we dont have inspections here in chi-town...
but yea that egr tube gets totaly clogged with crap.. i mean clogged solid!!!!

chillin014

iTrader: (67)

i mean if my y pipe was the reason i can install the old one...its just kind of a pain.

denami

i also failed emissions for this reason, but its because in MA if you have a CEL on and ur a 96+ u automaitcally fail they wont even put you on the machine. gotta love the new laws they passed in january, im bringing it to mechanic tomorrow to hopefully clear this code up along with another one.

chillin014

iTrader: (67)

looks like i just found my answer.
"EGR Theory. EGR serves one purpose and one purpose only. That purpose is to reduce Oxides of Nitrogen (NOx). "
now has anyone actually replaced this peace of sh*

chillin014

iTrader: (67)

yeah i hear ya. i wish the **** wasnt so strict here, i know its worse other places but why can't they tell that i drive a racecar and that their emissions stuff is restricting my DREAMS. its putting a restriction on my dreams....

chillin014

iTrader: (67)

i guess im gonna pay the 100 and get one from a local auto parts store

konak85

iTrader: (10)

i think someone on here said they got there system cleaned out by an auto shop, might want to look into that

Maxima_Joe

iTrader: (384)

egr can be a pain. What was the exact code? You could spend your $100 and still not fix your problem. I would take the pipe of and clean it as already mentioned. It may fix youir problem.

chillin014

iTrader: (67)

eh, it sounds tempting. but i am pretty set on doing this myself. so whether i clean the old one or get a new one, im doing it in my garage.

i hate taking my car to shops.

chillin014

iTrader: (67)

true dude. the code i got was...0302 egr system hi/low flow

Maxima_Joe

iTrader: (384)

I'm sure youve read this


0302
Diagnostic Trouble code 0302 points to a problem with the Exhaust Gas Recirculation system. The malfunction is detected by the Engine Control Module when no EGR flow is detected under conditions which call for EGR. Possible causes include:
- The electrical harness or connectors (valve circuit open or shorted)
- The EGR valve is stuck closed
- Weak or dead battery
- The EGR passage is clogged
- Faulty EGR temperature sensor circuit
- A leak somewhere in the exhaust system

The EGR Volume Control Valve may be tested with an ohmmeter. Disconnect the electrical connector. Looking at the connector half which is attached to the EGRVCV with the latch at the 12 o'clock position you will see two rows of three terminals. The top row is numbered 1-3, right to left. The bottom row is numbered 4-6, right to left. Measure the resistance between these terminal pairs:
2 1
2 3
5 4
5 6
... all resistance values should be 20.9-23.1 ohms at 68 degrees F.

Reconnect the EGRVCV connector halves. Turn the ignition switch ON OFF repeatedly. Verify that the EGRVCV shaft moves smoothly forward backward according to the ignition switch position.

The Exhaust Gas Temperature Sensor may be tested with an ohmmeter. The specifications are ...
- at 32 degrees F, 0.68-1.11 Megohms
- at 122 degrees F, 0.09-0.12 Megohms
- at 212 degrees F, 0.017-0.024 Megohms

chillin014

iTrader: (67)

yeah i've read that. ohmeter tests...i dont trust them a hundred percent.
if i can get an egr for 60 bucks or something around that price i'll just replace it for all the hassle of taking out the intake and throttle body to get down there.

chillin014

iTrader: (67)

i dont know how the f************ anyone gets the egr off. its so burried. i've got a wrench on the big nut that goes to it but the thing is not budging and its in a really bad position to put alot of pressure on it to loosen it.
there's alot of little tubes down there so im trying not to take too many off cause i wont remember how they go back on.

chillin014

iTrader: (67)

okay, i think if i get a big enough wrench i can extend it to that nut and then have enough leverage. i had a 1 1/8 wrench that was just BARELY too small so im gonna go buy a bigger one....tomorrow i guess. and some tubes since i broke some while taking them off.

chillin014

iTrader: (67)

OMG F********** EGR. i failed again with basically the same numbers after a brand new nissan egr. so now i gotta check the solenoid and the upper control valve and **** this is pissing me off so bad.

Maxima_Joe

iTrader: (384)

have you cleaned that tube yet? It's most likely filled with crap and what is propably causing your problems.

Mikey P

I'm actually having the same problem with my 93. I know why my EGR isn't working but I can't say what's causing it.

Start by reaching under the EGR valve and on the underside you should be able to push up on the rubber diaphragm underneath. If you do this at idle the motor should behave badly and nearly stall. This will tell you that the passage is clear enough to be introducing exhaust gas into the intake.

Next hold your finger on the diaphragm and raise the throttle to a little over 2000RPM. You should feel the diaphragm close and stay closed. Mine only moves for a moment before returning to its original position. For some reason my car is not producing a sufficient vacuum signal from the point ahead of the TB where the vacuum line comes from before heading in to the EGC solenoid. You may find that having a manifold vacuum tester will be useful.

One other thing I did to test my system was to buy a 2' piece of vacuum hose and go from the TB vacuum point directly in to the EGR solenoid. The solenoid (on the 3rd gen anyway) is only designed to prevent egr operation at idle, low coolent temp, high speed operation, and other conditions that you wouldn't be concerned with for an emissions test. If it works with a jumper hose then the problem is in your solenoid.

Like I said, I have a 3rd gen but I think the idea is the same.

-MP

7jackmack

If operating the egr valve manually causes no problems ,then your port and/or egr pipe are most likely clogged.

next - remove iacv and thoroughly clean the trough inside the intake plenum
adjacent to the egr pipe port. (this is all I did to solve my code 0302 about
2 years /60 k miles ago)
If that still don't do it, remove and clean the egr pipe which runs to the
port in the intake plenum.
If the car now stalls when manually operating the egr valve (at idle ,normal
operating temp.) you should be good to go.

chillin014

iTrader: (67)

do yall think i cna do this with no intake (i already took all that crap off i can bolt the tb on real quick)
i have a brand new egr valve in there now so i am willing to bet thats not the cause of this.
where is the pipe that people say is always clogged that goes to the intake manifold? i cant find that thing
also, with my NOX output numbers, the guy at the emissions place was saying that basically its like the valve is staying open the whole time

7jackmack

the pipe is at the back of the intake plenum close to the firewall -
you'll have to feel your way . It's an elbow that points down with
a bolt on each side of it.

7jackmack

http://forums.maxima.org/showthread.php?t=470051

useful info in the above thread.

chillin014

iTrader: (67)

i appreciate the help man, i've got the upper part of the valve taken out right now and i'm about to take out the iacv and this thing as well.
http://target.pg.photos.yahoo.com/ph...e2.jpg&.src=ph
the thing is...does anyone know if the high nox output would be caused by something being CLOGGED or something not closing. the plunger on both my old and new EGR seem to be working perfectly fine.
anyhow i guess i'm gonna start tearing out more.
that huge 32 mm bolt that connects to the egr isnt what gets clogged is it? that thing is a *****

Maxima_Joe

iTrader: (384)

14713 is the pipe that gets clogged

http://smg.photobucket.com/albums/v1...gAnch=imgAnch1

also
http://smg.photobucket.com/albums/v1...tart=#imgAnch1

chillin014

iTrader: (67)

Alright I'm takin this stuff off I think I got which things get clogged.
Your the man jack, too bad you weren't here before I spent 140 on that damn egr lol

chillin014

iTrader: (67)

14713 yes i attempted to take that hose off and it got stuck between that huge fawkin nut on 14120 either way, the hose was not clogged, caked a little, but not clogged. neither was the port going into back of the intake manifold next to the iacv, i could stick my finger through that hole. i cleaned it all either way. i cleaned the port going into the exhaust manifold too.
like i said, i dont think this is a matter of something being clogged because my emissions numbers show the valve is basically open all the time. and if its open everything is basically flowing, right?
maybe its someting electrical? i'll have to do that plunger test.

Mikey P

High NOx numbers would be caused by the EGR not opening to allow exhaust gas in; basically the opposite of what emissions guy told you.

This might be an excellent time to try and understand what's going on. You'll get more out of everything you area taking apart.

http://en.wikipedia.org/wiki/Exhaust_gas_recirculation

With the car off can you feel the underside of the EGR valve? If you can feel the rubber diaphragm then you can push it up with the car running. Pushing it up opens the EGR valve letting exhaust in to the intake. If you do this at idle the car should start to idle very rough or possibly stall. If this happens then the passage way is okay. With the car off disconnect the vacuum line going to the EGR, push the diaphragm up, put your finger over the metal tube that the vaccum line went on to, and then release the pressure on the diaphragm. If the diaphragm stays in place then the EGR is okay. If the diaphragm falls back to a closed position even though you are creating a tight seal on the vacuum point, then the diaphragm is no good.

If the diaphragm is good, and the car runs rough when depressing it at idle indicating that your EGR passages are good then you aren't getting a proper vacuum signal to operate the EGR. To test the vacuum signal go to autozone and get yourself a vacuum tester like this:

http://www.harborfreight.com/cpi/cta...emnumber=92474

You will remove the line going to the EGR and plug it in to the gauge. If you increase the RPM to over 2000 you will see the vacuum to the EGR go from zero at idle to enough to open the EGR (something between 5 and 10).

-MP

f550maranello2

iTrader: (2)

werd.. a simpler way to test it is to take of fthe egr hose and feel with ur finger if its getting suction after 2krpms.. reconnect and see if the egr is lifting after 2k rmps when reving quickly.. good luck if that dont work check the egr solenoid its the green solenoid right by the ks harness.. good luck

chillin014

iTrader: (67)

Okay I get what your saying. I'm gonna try the diaphram test on my old one and see if that one would hold a seal. I also need to get a vacuum tester and put my car back together so I can turn it on and test the system like your saying. I appreciate the help I'm gonna check it out as soon as I get off work.
If this is an electrical problem with the solenoid let me just say that I could not find that thing and didn't see its location on the egr photobucket fsm link from the stickies.
Btw the code is 0302

ghop95

My wifes max has been hard to start lately and sometimes cuts off after running for a few minutes. I ran the codes and get the "egr hi/low flow.." & "temp control sensor". Could the egr be the problem... has this happened to any of you?
Greg

Mikey P

There may be some diiferences between the 3rd and 4th gen solenoid operation but essentially on the third gen the solenoid is only there to prevent EGR operation by keeping that vacuum coming from the TB from reaching the EGR under these circumstances per the FSM:

"The EGR should open under vacuum except for these conditions
1) low engine coolant temperature
2) engine starting
3) high-speed engine operation
4) engine idling
5) excessively high coolant temperature
6) mass airflow sensor malfunction"

So to test the EGR system once the car is at operating temperature you don't need the solenoid in place as you aren't at low coolent temp, starting, high speed, etc.. What I did was purchase a 2 foot section of vaccum hose to jumper and eliminate everything from the TB vacuum source to the EGR itself. If the EGR then functions normally then your problem lies in that solenoid controlling the vaccum source. If it still isn't working then the problem may be with the vacuum source itself.

You can sort of think of the four basic pieces of the EGR system as the passageway (which may be clogged) that allows exhaust to flow in to the intake, the EGR valve (which could have bad diaphragm), the solenoid system (which might be blocking vacuum for a number of reasons), and the vacuum source.

My previous post sort of addressed the first two possibilities. The third possibility, the solenoid, is easiest to test by simply bypassing it at first to see if everything else works otherwise. And having a gauge is the easiest way to test the fourth part, the vacuum signal.

Good luck!
-MP

Mikey P

gshop95, my last reply was for chillin014, but yes the EGR system can cause the car to be hard to start and stall.

-MP

maxprivate

iTrader: (12)

its not the y pipe. i also have budget y pipe and greddy catback and rt cat. passed with no problem.

chillin014

iTrader: (67)

Makes sense to me, now I just gotta get out there and test it. Would be much easier if the stuff was more accessible.
Thanks a lot!

Mikey P

That was my thought to, but here is my emissions situation. The vacuum source (which originates in front of and to the bottom of the TB butterfly) is not providing a strong vacuum signal. My manifold vacuum is fine at about 18". When I first went through emissions my car had a WSP y-pipe, high flow cat, and 2 1/2" pipe going back to a 5th gen maxima muffler. Between then and my most recent emissions test, which I failed because of non operating EGR, the only thing I changed was my muffler. Its a walker turbo. Not an expecially aggressive turbo so I would imagine that it would have plenty of backpressure but for some reason I have just no good vacuum signal before the TB.

I found this post on the internet that sounds to be a similar problem and the answer proposed is a lack of backpressure.

http://autorepair.about.com/library/faqs/bl491b.htm

I wouldn't have guessed this and I really don't think that is what's causing my problem but I'm running out of places to look. And to add to this I know of at least one other 3rd gen max owner that greatly reduced his NOx by swapping back in the stock y-pipe. A result that surprised him as well.

I'm going to test this out by unbolting where the y-pipe connects to the rest of the exhaust and insterting some sheet metal to reduce flow and thereby add backpressure. I don't think this will do much, but as I said I'm running out of things to try.

-MP

chillin014

iTrader: (67)

Damn it sure as hell better not be my y pipe I passed last time with it too

Mikey P

ya, I don't see the y-pipe as the problem but I can't say until I try to reduce the flow. I tried holding a rag against the tailpipe to increase backpressure and that seemed to increase the TB vacuum a tiny bit, but not enough. My friend who was helping me had the theory that the restriction needed to occur further up because the there is too much compression of exhaust gas that happens in the length of the exhaust if you try to restrict it at the point of exit. He thinks the restriction needs to be closer to the engine. I may try that this evening or tomorrow.

-MP