HELp, Failed Emissions need advise.

[fc227 (fred)]

HELP !!!!


I went to have the GN Emission tested. It failed. Went to the DMV. Even though the cashed my check they will not renew my reg. Until the car passes.


Ok it failed two years ago, but they let me reregister it. Here are the readings from two years ago & today


2006 2008
HC - CO – NOx HC - CO - NOx
Limit 132- 0.42 - 921 132 - .042 - 921
Tested 78 - .71 - 802 57 - .02 - 1407
Fail Fail



The difference between this test and two years ago
1. New Cat
2. Replaced PCV hose, because it was collapsing.
3. Regular gas two years ago Vs 93 octane this year

Same chip, Mike Pitts emission chip, fuel pressure set to 40#’s


Now when I went to remove the cover for the EGR valve. After I removed the cover, I found the hose to the EGR disconnected. I do not now if I pulled the hose off removing the cover. But I did press the back of the EGR valve and the engine ran rough but did not stall. Plus I got black soot all over my fingers (must be when I was running the race chip, I could have popped the hose off at the same time.

Now with that said, I did block off the front and rear exhaust cross over when I did the heads. But I can’t remember if I plugged the center holes. I must not have since there is exhaust soot on the EGR valve. I really don’t want to pull the intake.

It looks like it running lean, so I will up the FP from 45 (BLM’s are around 134 now). This should help the NOx?


This is the first time I installed an emissions part and it got worst.


Any ideas, I am running out of time.

[fc227 (fred)]

here are the readings


2006

HC
limit 132 tested 78 pass
CO
limit 0.42 tested .71 Fail
NOx 921 tested 802 pass


2008

HC
limit 132 tested 57 pass

CO
limit 0.42 tested 0.02 pass

NOx
limit 921 tested 1407 fail

[Steve Wood]

unlikely you will pass nox without a working egr

[fc227 (fred)]

What do not under stand is why is the NOx so much higher than two years ago? When basically nothing has changed. Unless the EGR vacuum line was unplugged.

I got exhaust soot on my finger when I manually pushed the Egr valve. SO some exhaust is getting though.


Does making it run richer it up help reduce the NOx ? The new Cat should help if I do richen it up to keep the CO down.

[Steve Wood]

Making the exhaust gas temperature cooler thru exhaust gas recirculation reduces the nox

[Vkasm1]

Like stated above u have to fix your egr system. Make sure that PCM is commanding it to open and that that the valve is lifting. If u say that u lifted the valve with your fingers but the car didnt stall u might have restricted egr passages. You would have to clean them out. Also how many miles on engine? Is it possible that u might also have carbon on your pistons?

[fc227 (fred)]

It is very possible the pistons are carboned up. The car has not been driven for about 6 months. And it was only a 3-mile trip to the test station.

Would one gallon of denatured to 5 gallons of gas be to much alky ? . Since the computer will be trying to correct all the time.

[ULYCYC]

I would not use denatured alcohol. Either buy Seafoam or GM top engine cleaner. If it's know to be real bad, disconnect the cat before you start cleaning, As for lower nox, a few things will work. Higher octane, retard the timing or try an additive. Adding a few bottles of Heet drygas to a 1/2 tank will lower the nox a little. But remember as you lower the nox co2 and hc's usually start to rise. If you have a bad egr or you have the ports welded closed/removed it will be hard to do with above suggestions.

[fc227 (fred)]

Well, I got it to pass. It took 3 tries. I end up raising the F.P. to 50# to bring the NOx down, and with the new cat here are the results. Using "pitts" emission chip and a new CAT.


HC CO NOX

LIMIT 132 .42 921

TESTED 106 .17 774

[TurboJim]

Originally Posted by fc227 (fred)

What do not under stand is why is the NOx so much higher than two years ago? When basically nothing has changed. Unless the EGR vacuum line was unplugged.

If you look at your co readings, you'll notice 2006 is consideraby richer than 2008. A leaner mixture burns hotter (until about 16.2:1) which causes chamber temps to rise and NOx. In case you dont know, NOx is formed when the chamber reaches 2500* and the molecules in air seperate onto N and O. The richer mixture from 2006 cooled the chamber enough to reduce NOx. You need to a) get the EGR valve operating at a volume sufficient for a given airflow, b) richen the mix a tad, 3) use a 3 way catalyst 4) any combination or all of the above.

Jim

[fc227 (fred)]

Well, It passed. So I do not have to worry about for another year. Next test date is 5-15-09. But I my not have it tested again , until the reg becomes due again in two years. Then that will be the last test that as to be done. Because after that the car will be 25 years old. and no more emissions testing.


This is all a bunch of BS anyhow. IMO. Just another way to get money from us to give to the Government.