85 GL wagon smog fail

[two85s]

Hey USMB, I read through many of the smog related posts and want to post my situation up for your consideration.  My wagon is a very stock 85 dual range non turbo and has redone complete exhaust with new CAT in 2012 when it passed California smog.  This time (2014) it passed visual and functional yet still resulted in Gross Polluter status.  I will try loading photos with one of the smog report. Thanks for any help (keeping my wagon on the roads).  Aaron 

[coxy]

Needs a carby Service and re kit to bring all back to a fresh standard I suspect things like wear on the needle and seat in the float bowl will over time raise the float level making it run rich so address the carby, It may just need some fine tuning with an exhaust sniffer to clean up it's act 

[two85s]

Thanks for the input coxy!  The carburator had a bit of work done to it a few years back when it looked like a gasket was sliding out of position.  I will look back at receipts to see if what was done to the carb is detailed.  I have recently replaced the air filter, PCV filter, PCV valve, and the fuel filter.  I was going to replace the EGR valve but the part from Rock Auto had no tube on it to attach the hose like my EGR has so I kept the one I had.  Aside from getting it good and hot on the freeway, I didn't do much else prior to attempting to smog it because 2 years ago it passed with no problems....the numbers on the smog report photo I attached hopefully are meaningful to members on USMB.  Thanks again for the help, Aaron

[ruparts]

hi,

  i'm not saying you need another cat, but i can say the aftermarket cats that shops put on here in tx are so bad they usually won't pass even 1 year later. ( we only have to pass smog till the car is 25 years old, then no test , just the safety stuff).  the quality of aftermarket cats  is very bad,  there should be some fed standard they have to meet to even be available on the market, i don't think that is the case though.  usually a good tune guy can tell what is not right by which of the numbers are bad,  an o2 sensor is  cheap enough to throw on for good measure,  but a good diagnostic guy can narrow it down.  

[two85s]

Thanks ruparts I appreciate the feedback.  The mechanic who put in the CAT and the exhaust (very nice tube work IMO) 2 years ago seemed confident that the CAT was good and there were no exhaust leaks (however later I realized he said so without running the car--his shop was "too swamped").  The mechanic told me it would be very difficult to narrow down the problem and would likely be + or - 3hrs diagnostic work for starters (ie $280) plus he was so busy that he didn't know when could "get" to it.  So, I thanked him and drove the wagon home, where it now sits with expired tags.  The owner of the smog test shop hinted that the smog report readings could mean an exhaust leak or ??? .......he couldn't say.  I am wondering if the smog report readings would likely be caused by an exhaust leak?  Thanks for chiming in ruparts and take care, Aaron

[Gloyale]

Clean and lube the advance weights in the distributor.  they get sticky and hold timing too far under light loads/unloaded

 

Also clean out the EGR ports and the Vac port that feeds it.  They get cruddy and it's high NOx you are fighting so EGR will help.

Edited May 25, 2014 by Gloyale

[two85s]

Thanks Gloyale good to hear from you!  I will do what you said.  Yes high NOx....everything else passed.  Do the EGRs commonly need replacing or can they be cleaned effectively.   What about forcing/altering the EGR to be always open?  Is a exhaust leak possibly the high NOx reason?  Thanks for the help, Aaron

[TallonX]

http://www.crypton.co.za/Tto%20know/Emissions/exhaust%20emissions.html

[elgigante]

ive passed every car i own that failed smog this way....

Drive car to empty all the gas and warm the cats
Add 2 Gallons of Chevron 91 ( Or highest in your area)
Then add 1 gallon of e85
then go smog
Thank me later.
The e85 isnt going to do no harm since it will be gone and flushed out the system after you smog.
your reading will be way lower.

[two85s]

Hey elgigante thanks that sounds interesting.....and I like it.  What types/ years of cars has this worked for you?  Aaron

[two85s]

Also, from what I've researched it sounds like if I have a new CAT put on.  The car will then pass smog without a doubt.  Is this correct? Thanks again, Aaron 

[elgigante]

2 nissan 240 sx
1 92 bmw 325i

just make sure you fill up after to get the e85 out.

everytime i do it. i go to a place where they offer a free retest, after i fail the first i go fill it with e85 and come back 30min later and the dudes are always like
what in the world, "you know you only have one free retest right" haha
works everytime.

[skishop69]

Clean and lube the advance weights in the distributor.  they get sticky and hold timing too far under light loads/unloaded

 

Also clean out the EGR ports and the Vac port that feeds it.  They get cruddy and it's high NOx you are fighting so EGR will help.

 

+1 If your O2 readings are high, it's because you're running lean, IE, not getting enough fuel or the EGR is not functioning correctly. You're NOx readings are high because running lean causes higher than normal combustion chamber temps. The EGR system was designed to cool the combustion gasses under specific load conditions. If the valve is not working or the lines are plugged then it will not do its job. Over advanced timing also causes excessive temps as well. You have a set volume of air and fuel being compressed then ignited. Once ignited, it expands in volume. Ignite it too soon while still compressing it and now you're no longer compressing the fixed volume, but depending on how far in advance it was ignited, you are compressing 1.5-2 times the volume. The more volume you try to compress, the higher the combustion temp and the more resulting increase in NOx. I doubt it's carb related since you didn't mention anything about a lack of power or poor runability issues.

[two85s]

Skishop69 thanks for chiming in and offering help.  I will be doing what Gloyale said and you +1.  The idea of adding certain high octane gases or additives to spike the fuel with a near empty tank sounds good too.  The wagon has good power (noteably more after I put a new air filter in) and Idles well about 800-900 rpms so yeah I think the carb is okay. 

Regarding the timing:  smog shop checked the timing and the report says it is "09 BTDC" and they passed the timing.   So is that advanced or correct? 

 

No one has said an exhaust leak would be causing the high NOx so I am ruling that out, correctly I hope...

Also, would a new CAT be a "sure to pass" last resort?

 

Hey TallonX thanks for the link. I read it and am learning more about this than I expected. Thanks USMB members for the help, Aaron

[AdventureSubaru]

No guarantees on the CAT as a sure to pass, but it can cover up a lot. Like putting a new filter on something, it will catch more stuff which give's you a much better chance, but would merely be a band aid to whatever else may be going on.

 

Lots of places slap new cats and o2 sensors as the fix for failed smog.

[two85s]

Hey AdventureSubaru thanks for the input.  I will be using the tips I have been given here and will report back the results.  The mechanic said make whatever changes are needed and then bring it to him for a test for $40.00.   Will be close to two weeks before I have it retested.  BIG thanks everyone who offered help/ tips, Aaron

[roadsubiedog]

what causes high NOx? those numbers are high. im in CA with a 84gl. one time the EGR valve was clogged. its easy to take off and clean out ports. you can check it by pushing in diaphragm at idle and if it is working the motor will almost stall.  I cleaned it up and then it passed. the diaphragm could be bad. I took one off a pick n pull car for about 10 bucks. cant remember. usually they are just clogged.

 

what does e85 do?? not sure.

 

also you can idle it and feel for exhaust leaks at manifold and other connections. had to replace a couple gaskets for less than 10 bucks.

 

check to make sure 4 nuts holding down carb are tight. mine were loose one time.

 

timing has to be at 8 degrees . mine was at 12 one time. 9 degrees is fine.

 

change oil, high octane gas, run some "Guaranteed to Pass" thru a tank of gas. buy at wal-mart or amazon.com

 

make sure all vacuum line are connected and/or not cracked.

 

you can also run hotter plugs. but I think that helps burn hydrocarbons, not sure what causes high nitrous oxide though. all the little things help. get it nice and hot before retest.

 

is the cat even working? did they aim a temp gun at it?

 

what kind of mileage do you get? I was getting 25mpg before doing everything. afterwards I was getting 30-33 mpg. that's a good indicator. hope these suggestions help.

Edited May 28, 2014 by roadsubiedog

[two85s]

Hi roadsubiedog,

 

"timing has to be at 8 degrees"   The smog shop said mine was 09 BTDC

 

"is the cat even working? did they aim a temp gun at it?"  The mechanic was confident the CAT was still good.  I saw no temp gun used by the smog shop.

 

"what kind of mileage do you get?"  My milage is right about 23MPG last two times I checked it and the wagon has 215K miles.  Thanks for the tips and help, Aaron

[roadsubiedog]

9 degrees is fine. they give me plus or minus 3 degrees here.

 

23mpg is kinda low ( unless you drive fast and do a lot of driving around town ). I've had 4 different gls with over 200k on them and the worse I got was 25 but after changing filters,oil, gas treatment and such I was getting 30 or more. oh, I drive 55. when I go 65 , I only get about 25.  

 

something sounds clogged.

 

btw I hate the smog laws in CA. they always try to find something and when they do they quote you a price to fix it. one time they charged me $129 to find out what was wrong and fix. the other mechanic pulled me aside after it passed on the retest and he told me he was quitting because of how they operate. he told me all the smog mechanic  did was raise the idle a couple hundred rpm. that's IT!!! after that I tell the smog shop ( a different one ) i'll do the work myself and they always act irritated.

 

the only real reason I ok'd the 129 dollar diagnostic is because I was selling a subie that I bought for 3500 and resold for 6500 after only putting about 50 miles on it. it was a special construction .

 

I'm curious what you do to improve the emissions and the retest results. im trying to find out what cause high NOx.

[roadsubiedog]

everything has been covered on high NOX  on this thread....timing ( yours is ok ) EGR valve function, lean air-fuel mixture, defective 3-way cat, and or combustion chamber deposits.

[elgigante]

just wondering, do they do evap checks? pressurize the gas tank

[two85s]

Yeah, I am glad to look into it myself (save money) especially with the help given from USMB members.  If I could get 30+ mpg that would be great and maybe miraculous.  like Gloyale said in a post, "clean and lube advance weights in distributor and clean/ check EGR and ports etc."  This is where I start.  Also items you and others recommended like fresh oil and filter, high octane gas, (E85 sounds interesting), check for vacuum leaks, are related and important too.

 

Would 8 degrees be better than 9 is a good question?

 

"just wondering, do they do evap checks? pressurize the gas tank?" no elgigante the smog shop did not I am pretty sure.

 

I will post what I do and a photo of the results from the next smog test.  Thanks for the help USMB

[roadsubiedog]

one degree shouldn't make a difference as far as I know. im surprised they didn't do an evap test or check the gas cap. I usually buy a new cap every couple years. 4 years ago my gas tank failed the pressure test with a full tank. I went to another shop after fixing a few things and using some gas and it passed the gas tank check.

 

I started asking around for a cool smog shop and found an ol school shop that looked like it has been around for a hundred years. the guy is cool and tells me what I need to do if it fails and doesn't charge me for a retest. but he cant rig the machine. ha ha.

 

ive got a smog check coming up next February and am already checking things out this week on my vacation. my 84gl has 327.000 miles on it and I put anywhere from 255-425 miles a week on it going to work. all highway miles. it runs like a top ( knock on my wooden skull ) and gets between 32-37 mpg depending on driving and weather conditions.

Edited May 28, 2014 by roadsubiedog

[two85s]

You guys are correct I think they did do both (pressurize the gas tank and vacuum test in the engine bay) at the smog shop.  Yep, I looked at the report and they are both listed "Pass".

I don't know if I have a three way CAT but it is pretty new (2012). 

32-37 mpg is fantastic and I would like to add 10 mpg to the 23mpg I have noted.  Your 84gl serves you very well as has mine, I bought my 85 wagon in 1995 while living in Denver and it does have some classic snow country cancer issues.  I have had two other 85 wagons but they both turned into parts donors.  I will post what happens regarding this smog once it's done.  So, thanks for the advice and best wishes, Aaron

[skishop69]

E85 has a lower BTU rating than gasoline. Diluting high octane gas with it will lower NOx and sometimes CO2 readings. Since it has a lower BTU, it will burn cooler reducing combustion temps and thus NOx. You have to use very small amounts as E85 is deadly to rubber components.