robbe_iroc

Hi there.
My GTO LS2/T56 swapped -89 Iroc won't pass the emissions here in Sweden. Not even close to make it pass the sniffer.
We hare a maximum limit of 1.0 Co2 and my low mileage LS2 came in at 2.5...My old high mileage L98 always managed around 0,2-0.4.
I´m running 2 magnaflow full flow cats. The right one is in the stock cat location, and my driver side one is about the same distance from the engine.

I´ve been checking the tune with a EFILive tuner guy here in Sweden, and he thinks it´s really strange, because he can't find anything wrong or strange in either the base tune or any thing related to sensors/computer readings during 20 minutes drives.

Where do I go from here? Anyone had any similar problems? The engine is a stock and unmodified 2006 GTO unit exempt a full flow cold air intake with a BIG K&N filter on it.

1nasty86

iTrader: (5)

that is strange.... sorry i cant be of more help but id think the tune was off

robbe_iroc

Yepp. It is strange. The tune is 100% original GM factory tune....
And as it is now, I´m not allowed on the streets...:-(

Twin_Turbo

iTrader: (25)

Are you still using the fly by wire throttle? Converted with a FBW pedal?? Where did you get the tune?

88 350 tpi formula

iTrader: (9)

do you have efi live or him? I would like to see a log or even verify the tune is truly stock..

what were the other gas levels?

also those cats wont even come close to what the factory cats do. it reminds me of all the catco cats people have installed and set a p0420 code again and again until the owner drops to their knees and buys a factory cat

robbe_iroc

"My" tuner is a EFILive retail guy. And because of my location i Lappland..10 hour drive one way to him, we do all the tuning with a Autocal thingey. So I drive, save my 20 min drives as files and send them to him and he checks what the car/computer is doing etc. Went by a shop today to get the exhaust readouts. My old (before the changed tune) CO2 readings were actually 0.7 and the limit is 0.3 at 2500 rpm. He changed the "stoich value" to 14.13/1 which is something that should be preferred to for E10 fuel, and now my value came to 0.4, which is getting close to the limit. Normally people here in Sweden just add some E85 to the fuel and most values goes to 0.0 or very close to that, but last summer I couldn't get below the legal limit even with 25% E85 in the tank..
I think my 2 MF cats are having big trouble getting hot enough to do a good job. Stock the GTO have 4 cats, and 2 of them are sitting virtually on the manifolds, so they obviously get very hot. So well se what the tuner guy comes up with during the weekend. The garage guys told me that any tiny bit of leak in the exhaust before the O2 sensors could create this problem swell. So I´ll check the exhaust for any leaks that I can find. The egr-ports on my 2002 SS manifolds easily leaks for me. I´ve built block off plates for the holes myself out of some 3-4 mm steel plate, and it seems it might be time to make gaskets out of copies or similar. hard to tell/hear if there are any leaks there too...

robbe_iroc

Yepp I´m using the FBW pedal from the GTO. Cant remember the specific other gases. They were all in the acceptable levels. O2/Lambda reading was 1.02 which is about as good as it can be. HC was OK too.

robbe_iroc

Hi there again. These are short video clips of the emissions readouts from the test station last week. Watch how fast and how much the engine changes the value on the idle CO2 value... HOW can this be? The car didn't even come close to pass the emissions...So now I´m allowed on the streets for 3 more weeks, after that it´s game over :-(
Some mechanic friends suggested that I´ll do a compression test to see if a lifter oct valve is malfunctioning an causing this dilemma. So I´m gonna do that tomorrow, but besides that I don't have much to go for. Any suggestions?

Engine at idle

http://www.youtube.com/watch?v=dz3iVrQCYDQ&feature=plcp

Engine at 2500 rpm

http://www.youtube.com/watch?v=gYuWa...hannel&list=UL

robbe_iroc

I forgot to mention that in this test I was running a mixture of 50/50 E85 and regular 95 octane "Swedish" pump gas fuel. That was an effort to try to get below the 0.3 co2 limit at 2500rpm´s. It´s really strange that the co2 went up/higher with this mixture compared to 100% 95 octane in the tank...confused

Apeiron

It failed because CO2 is high?

robbe_iroc

Yepp, The limit is measured at 2 different rpm levels. At idle the limit is 0,5 and at 2500 rpm the limit is 0,3. My idle co as seen in the video is constantly changing like crazy between 0.014 and all the way pup to 1.4...And the 2500 rpm level is also changing a lot and to high at all times..A health running/properly tuned engine should be at around 0.0

Apeiron

Are you talking about CO2 or CO?

cam-

We've not ONCE had an aftermarket cat pass emissions here in Canada. Stock converters are the only way to make them pass in my experience. Also get them as close to the headers or manifolds as possible and make sure they're good'n hot.

five7kid

iTrader: (14)

My son has Magnaflow spun cats on his LS1 clone in his S10 Blazer, and it passed the dyno sniffer with no problems.

High CO is caused by a rich mixture. That's why an exhaust leak can fool an O2 sensor. A weak O2 sensor can also cause the PCM to add fuel.

cam-

^dis. Especially if you ran it untuned if they get soaked with fuel they go bad

robbe_iroc

I was talking about Co not CO2, sorry for the confusion that I caused by that. The first times we went to the emissions test last year it was running the stock LS2 GTO tune. A car without cats should be able to pass these CO levels. My dads high mileage carburated 1986 305 Pontiac Grand Prix went through the tests with the cat removed just 2 weeks ago. In that car we added 10 liters of E85 to 50 liters of 95 octane pump fuel. The CO level at 2500 rpms was 0.01.....
My friends cammed LS1 1998 Z28 passes the tests with random technology cats too, so its strange I think.
But yeah, I think that the MF cats are a bit crappy now aswell, but they are brand new and the car has alway been running fine and all 8 plugs are nice and white aswell.
But I´m pretty sure that the previous owners have been running a Magnusson type blower on it. The LS2/GTO coil covers have a slight scuffing in a place that occurs on cars with those type of blowers+ there are signs in the intake bolts that indicates that it has been removed swell. I bought the engine/tranny from Cleveland Pick a Part as a LOW mileage 2006 GTO dropout. And it was supposed to have great compression and to be completely stock...Well it might be NOW, but...has it been before?
I talket to my tuner to see if there was some kind of supercharger tune in there that adds fuel, but he said it´s the stock tune....
Well, what the hell can I do? As I said, my dads car passed without a problem at without cats, so I feel that mine should too even with crappy Magnaflow cats, they can't do things worse?

robbe_iroc

Checked my compression a few days ago, and it was 180psi in 6 cylinders and 190 and 200 in the two other ones. That was on a cold engine, so the compression seems fine to me, or?
Gonna check the fuel pressure tomorrow to see if there is anything strange going on in there. Maybe the fuel pressure regulator in my LS1 body tank is going bad..I don´t know. Trying to check anything that I can. The car is banned from the streets within a week now..

Anyone that know how to measure the coil packs on a LS2? What readings should I get?

robbe_iroc

Fuel pressure was steady at 58 psi....SO the search goes on.

vwdave

Now when you say "Full Flow" do you mean "High Flow" ?

robbe_iroc

Hehe, well here in Sweden we say full-flow when we mean high-flow ;-)
These are the ones I got anyhow.http://www.magnaflow.com/02catalytic...niversal=53006

robbe_iroc

The main concern in this matter with the high CO reading is that it´s going up and down ALOT. If the value would just stay in "about the same" numbers It would be easier to troubleshoot and/or add/replace these cats with more cats or put better ones in there. But when the value goes up to 1,59 for a few seconds and then dips down to good numbers as in 0.02 for a few seconds and back up again...What is it that makes it go up and down ALL the time?

robbe_iroc

Here are my tunes if anyone feel they have the time to check them out...Got a new tune from my tuner (swap-4)about a week ago, but the CO stayed about the same, even tough the car feels ALOT weaker....Swap -1 is supposed to be a completely stock GTO tune with the VATS and rear OS delete etc?

http://ls2.com/forums/showthread.php...8#post14885718

robbe_iroc

I moved the MAF about 5" away from my k/n filter and then the numbers stopped going up and down at idle. BUT the CO reading is still 0.7-0.8 at 2500 rpms. Even with the other tune (swap-4) Driving with the swap 4 makes the car hesitate and studder alot, so I changed back to swap 1 during driving, and the freakiest thing is. It studders with the Swap 1 (stock) tune now too....

Is there anyone that are able to look at my tunes and see if the tuner is doing something crazy?

robbe_iroc

I bought a complete used C5 Corvette exhaust system for 1000 SEK (about 150 USD) a while back ago. Cut i apart and made a new "y-pipe" using all 4 C5 cats replacing my previous y-pipe that had 2 Magnaflow cats in it.
Went to the test station and here the fun part: IT WORKED!!!

CO level 0.00 @ 2500 rpm (limit in sweden 0.7)
HC level 1 (limit in sweden 100)

I never would have thought that the stock cats are sooo much more efficient than the Magnaflows....I mean, the Magnaflows were not even race versions and they were new. The C5 ones are many years old etc etc.

OK but now that I did pass the emission testing I´m gonna put the Magnaflow pipes back again because the 4 C5 ones are killing power easily noticable when driving, and thats never a good thing ;-)