redraif

So I took the car to get tested! It failed...the reading were way higher then last year!

How far do you have to driver to really get the cat hot enough to really do its job?

What happens if all the emissions pass solution is not thru the gas tank. There was still a bit in mine!

Readings last year Allowable
hc--------------------- 034 ---------- 152 PASS
co--------------------- 0.01 --------- 0.97 PASS
no--------------------- 0793 -------- 1082 PASS

Readings this year Allowable
hc--------------------- 0145 ---------- 152 PASS
co--------------------- 3.68 --------- 0.97 FAIL
no--------------------- 0330 -------- 1082 PASS


So what would have cased the overall increase, but esp what is casing the CO to be so high? Not running the car long enough to heat up the cat? Having some of the emissions pass stuff still in the tank?

Thought it might be the emission stuff since I think its a cleaner. If its breaking up the deposits in the engine, the car would spit out more CO, right?

KED85

I had exact same thing happen to my ride.
My cat was destroyed by the rich running engine during cold.
I need replace the cat, oxy sensor.
And change my oil, too.
Then I'm good.

Mr Badwrench

Here's a few things to check.

Engine grounds
shorted injectors (real likely) Should be about 12 ohms hot
leaking fuel pressure regulator
gas in crankcase
bad MAF or air leaks between MAF and intake plenumn
retarded ignition timing
grounded or bad o2 sensor

redraif

Well got the car scheduled for a cat replacement today! Have to dorp it off tonight and leave it! Hopefully that will help!

On the other items...I will check them out as well. We are going to be taking the intake manifold apart when we do the intake swap, so that should be the perfect time to check the injectors! Fuel pressure reg is new! checked with fuel pressure gauge and pressure all seems good! MAF...not coding for anything! Timing at 10! Will replace o2 with cat replacement!

So those items can lead to a high CO...huh!

Mr Badwrench

Make sure you take it apart as hot as you can get it. Injectors sometimes will not read shorted at room temp.

redraif

Thanks! good to know!

Mr Badwrench

I forgot to mention the coolant temp sensor for the ECM. Throw a scanner in there and check it.

TomP

The only thing off was the CO?

So how old is the air filter?

Mr Badwrench

Here in Vegas we see shorted injectors all the time. With our extreme heat and lots of alcohol in the gas, injectors get tore up badly here. Basically the way the circuits are laid out if one injector goes out it will pull the other 2 down on that bank. The ECM will not be able to control the injectors and will start dumping fuel.

You can take a quick test by heating the engine up and in the front of the plenum there is a connector for the injectors. take a ohm meter and on the injector side of the harness probe the power feed and the grounds of the injectors. You will be testing 3 injectors at a time so a little ohm's law will fall into place and of course resistance changes with temp. You should read about 4.3 ohm's hot if they are down below 4.0 then chances are real good one is shorted.

KED85

My car problem is caused by the coolant temp sensor not being replaced when I did my swap boogie.
I thought....and it came back to haunt me.
Change that sensor anyway (it's like $6-8 cost).
I'm doing my oxy sensor & CC & fresh oil anyway as those are easiest to tackle for me at this moment. And that will cure my problem but not remove the cause (a worn down sensor).

redraif

Its a K&N...it could use a good cleaning! Prob been a good year since we cleaned it good come to think of it!

TomP

Put the K&N on the shelf, and put in a $6 walmart air filter just for the test. After the test, put the $6 air filter back in its box and put the K&N one back in your car.

If the cat was bad, your HC would've failed too. High CO just means you're not getting enough oxygen in to turn CO + O into CO2. Since your other #s were so awesome, I can't see something "complicated" causing the problem.

And you have an aftermarket cam in there too, right?

Here was my results from the NJ dyno test, and what I did before the test: https://www.thirdgen.org/techbb2/sho...hreadid=232064

redraif

Wonder if anyone makes a paper filter to fit my SunCoast box? Oddly all my test areas were up form last year...

Yep I ahve a health cam in there...though the car has passed for 3 years with that cam. once before with the 3.4!

heck my 1/4 mile times were not as good as I would have hoped compared to last year either! dropped 200#, and fixed the tranny, drag radials, and still only pulling 16.7!

Something simple...what happens if the emissions passing fluid is not all thru the tank at test time? Would that produce an excess of CO?

2_point8_boy

Looks like your O2 took a crap. Don't worry about driving the car to get the cat hot, it's overrated. by the time the car idles and they actually test the emissions, the cat has cooled down again. that's just something that people think works, but when you look at it rationally, it just doesn't work.

My money is on the O2 crapping out. sometimes they just cook and go completly open, then you get a rich command from the ECM. Full pulse width on injectors. do you sometimes get an O2 lean code when you cruise? that's where I would start looking.

Emissions passing fluid is SNAKE OIL!
Don't worry about it, it doesn't do crap...EVER!

redraif

Would the car code for a bad O2 though?

Oh and last year we checked with a heat sensor gun the last time we tested my emissions...

I had the cut out open then capped it and ran it some. Then tested...it failed checked the cat not hot enough. Went and drove it longer checked cat...hot enough then it passed... so there is a bit of truth...just no clue how long it takes to heat it up!

2_point8_boy

<-------- CA Smog Tech

You have to litterally drive the car long enough to get it hot, then pull directly into the bay and test it immediatly. More than likely you just got lucky, for the most part, this kind of thing just doesn't happen. The cat has to be minimum 600*F before it even barely begins to work. The O2 too. As long as everything on the car is working correctly, you shouldn't have to do a special warm up, it should just go on the machine and pass.

If you want, I can prove it with my test results from this last April, >220K miles, and no warm up.

The car won't code for a bad O2, but if the O2 dies completly, you could get an O2 Lean Code because it is open and the ECM sees low voltage for a long time.

KED85

2_point8_boy<-------- CA Smog Tech and I recently tried to pass smog my Firebird.
Last time the car blew thru with some zero readings.
Right now I failed due to high CO readings.
I know I have no "cat guts" in my CC housing and I am quite sure my Oxy sensor is toasted.
Due to poor running car at cold setting, due to bad cold sensor on intake.
We tried, what 3 times I thik, different ways.
I'll be backing passing soon due to swapping on a new CC and new oxy sensor and fresh oil.
I haven't tuned up the ride in over two years but shouldn't due to other readings (besides high CO reading) were within acceptable limits, not indicating poor conditon ignition parts.

redraif

Well with the exhaust working being done the O2 will doubtfully survive the transfer anyway...so new on there....then the new cat has to make a diff! Will see when car comes back! I can't wait! Dying with anticipation to get going on it!

redraif

Ok here is what happened with the new cat (dynamax 3in high flow) & new exhaust system (mandrel bent 3 in) ...same o2 sensor!

Readings with new stuff! Allowable
hc--------------------- 0011 ---------- 152 PASS
co--------------------- 00.00 --------- 0.97 PASS
no--------------------- 0786 -------- 1082 PASS

Big difference, EH!? I thought is was strange how the NO was low before and now is higher...but it was higher when it passed last year too! Go figure!

My old cat...I picked it up once it was of the car...I heard clunk, clunk! the strata had broken loose...good thing I mostly run with the cut out open, or I would have had an issue!

Oh and to be sure this new cat stays fresh for each test year...I got him to flange it at each end and make a straight pipe replacement for "track use" hehehehe! I'm taking it off for daily driving...going to knock the heat shield off my old dead cat and fake it up on the straight pipe! Then I will have a fresh cat come test time next year!

2_point8_boy

Higher NOx isn't strange at all.

It's all because of the O2 sensor. A cat needs a good one to work right.

When the engine is on the lean side, it puts out a lot of O2, which is awesome for oxidizing HC and CO, so those nmbers go low.

When it's on the rich side, the CO and the Rhodium in the CAT reduce NOx into N2 and O2.

You have to have it switching QUICKLY in order for this to work properly. If the O2 isn't switching about 5 times per second, it's toast.

See, the problem that you're gonna have is next time you get it tested. Your engine is still going REALLY rich (3% co) like it showed ont he test. CATs really like this. they get contaminated and melt so fast it's not even funny like this. I can say, with almost certainty, that next time you get the car tested, you'll be installing anohter cat on it, simply because you put a bandaid over a bullet wound.

I wouldn't just stop worrying about it if I were you. Even though you have a while before your next test, it's a shame for someone to just throw money into a car installing a new cat evey time they need a smog test instead of actually taking the time to diagnose and fix the problem correctly. Pus the fact that eventaully, the cat just won't be able to help anymore because so many other problems exist, it can't keep up.

KED85

I have to "clear the computer" for the new oxygen sensor, correct?

redraif

Do you? We just put the new one on last night and thought nothing of it!

redraif

Thanks for all the info on this...not sure how you keep it all straight. The car running rich is due to 19lb injectors in my 3.4. They 3.4s came with 17s, but with all the mods we have done, it did not make sence to use the smaller injectors.

But this obviously has the car running rich. That is why I had a test pipe made. The new cat can come off and be safely stored till the tune is right or till emissions time comes again! So as of last night...the cat is off the car, safe from harm!

The new custom chip is going to be going in a few days...it has a 20% cut in fuel to tone down the larger injectors. This I will rin with and see how it goes. From there I will do the rest of my modifications to the engine. If it goes as I plan I can then step to the next chip which only has a 10% fuel cut! Hopefully this will completely iron out the tune and end my running rich problems!

So we have not just dismissed the problem by any means, I'm just done with the DMV problem!

KED85

I'm gonna be "smart" and atleast give that idea a try.
Don't doubt it may certainly help.
I'm discovering the older computers do not process information FAST ENOUGH to "keep a code or even read it", as the sensor problem may be a "flash", not the required time for computer to read/store code.
In Helms book it says the engine problem conditions must be "met for 10 seconds" to read/store/retreive some problem codes.
Apparently clearing the computer gives the car a fresh start at "relearn", if these statements make sense, not to me, but the car ECM!

redraif

Ok I follow you! Guess when we change the plugs tonight I will do that as well! Then off to the dyno Thurs...HEHEHE! Then in goes the new chip...bye buy EGR, and bad gas mileage!