tuning to pass emissions

[dsmike1]

so i recently finished my gst build. i tried to get it inspected today and it didnt pass. heres the deal, i got all of the monitors fired up with no cel. pulled it in the inspection bay at my shop today and my boss plugged it into the computer. apparently, here in Rhode Island, a 97 gst is exempt from the standard obd2 plugin and inspect style inspection. so now my boss had to do a two speed idle test and stick the probe in my exhaust and rev to 2300rpm. well i have no cat converter so it booted him out of the test showing the hydrocarbon reading. well, i am allowed 600 hydrocarbons. the gst spit out 1800 now for the questions. should i just pull fuel like a mother at 2300 rpm to get this thing to pass. and if so how should i go about doing it. lower fuel pressure? adjust deadtime? something ive been thinking about was locking it in open loop and dragging the fuel delivery tabs down from 0 to 3000 rpm? and to top it all off i got home today and the laptop i use for link will not start up. so im heading out now to buy a new laptop. please any help would be great i need to get this done by friday.

 

[hotrodssnova]

You could try some e-85. I thought I seen a thread on it when I was looking to pass the treadmill emissions here in Houston. You could always throw a cat on it and make sure your egr is working too.

 

[dsmike1]

e 85 is hard to come by around here. no chance of a cat. I made my downpipe to meet the cat back no way im cutting it. and egr is blocked off. theres got to be a way around this

 

[sbiggi]

Is your o2 sensor dead? Running 14.5:1 is best for emissions, running lean will cause high nox, not sure what all they look for on at test in your area.

 

[5150DSM]

I just passed in Cali. I fixed a couple of small vacuum leaks, replaced the PCV and dropped 5% fuel at idle and another 10% at mid on the MAFT. This took care of high HC's and high CO%. HC's are partially burnt fuel so don't lean it out too far or you'll create a lean mis-fire which will raise HC's dramatically. I shot for 15.1-15.3:1 at idle and 14.8-15.1:1 at 2500rpm. Worked for me.

 

[dsmike1]

my o2 only has about 730 break in miles on it. its definatly not dead. my wideband swings around 14.7 untill i hit open loop. we measure nox also thats a good point i wasnt thinking that deep into it. i just need this thing to pass

I just passed in Cali. I fixed a couple of small vacuum leaks, replaced the PCV and dropped 5% fuel at idle and another 10% at mid on the MAFT. This took care of high HC's and high CO%. HC's are partially burnt fuel so don't lean it out too far or you'll create a lean mis-fire which will raise HC's dramatically. I shot for 15.1-15.3:1 at idle and 14.8-15.1:1 at 2500rpm. Worked for me.

this is the exact type of answer i was looking for. sorry im new to link, how did you pull 5% and 10%?

 

[5150DSM]

I'm tuning with a MAFT. So for me it was just a couple of clicks on the dials. Couldn't tell you on 'Link, haven't used it. Maybe you could use a target AFR table for the specific rpm range you need. Also, if you measure NOx you really need to be concious of how lean you go; lean mixtures burn hot and oxides of Nitrogen are formed much more readily in an excessively hot combustion environment. Hope fully some link users can help you with the adjustment tech you need. One more thing, I pretty much guarantee you won't pass (legitimately) without a cat. Start looking for a buddy hook-up/pay-off scenario.

 

[dsmike1]

yeah i have one of those buddies but they are expensive. thanks for the input

 

['97boostinGST]

Idk how emissions are in Rhode Island, but here in Cali if you don't have a cat AND the EGR, they won't even touch your car.
Unless you have the hook up.

 

[donniekak]

You need a catalytic converter.

 

[nickk90]

Pick up a stock exhaust system and put it on for testing then remove it after you get your stickers.

 

[dsmike1]

Idk how emissions are in Rhode Island, but here in Cali if you don't have a cat AND the EGR, they won't even touch your car.
Unless you have the hook up.

Well I work at the shop that it is Being inspected by. But instead of helping me out I think my boss considers it a challenge for me to get It to work. Or he is just ammused by it.

Pick up a stock exhaust system and put it on for testing then remove it after you get your stickers.

I wish I could but it would never work. I have an hx35 and I made a custom 3 inch downpipe that is one piece from the Turbo to the intermediate pipe. I never would have made a test pipe but I figured it was obd2, no reason to. Then I got shafted by this state once again.

 

[Hal]

You didn't get shafted by the state.

The emission rules were there before you chose to modify the car.

You CHOSE to ignore them and failed to plan accordingly.

Now you have to spend extra time and money to do what you should have done in the first place.

Test pipe with v-bands, cat with v-bands.

Ten minutes to swap them.

 

[daren_p]

Plain & simple, you need a CAT.

If its a 2 stage idle test, its not a loaded test, then they don't test for NO, which means adding an EGR will do nothing.

If you have a working O2 sensor & fuel trims are inline, your not going to "tune" in a pass. The ecu uses feedback from the O2, in closed loop, so you make an adjustment, the ecu will tune it right out. You adjust it enough, it will throw a CEL.

Again, you need a CAT.

You can try all the little things to help the car pass, but it still won't likely be enough.

 

[dsmike1]

You didn't get shafted by the state.

The emission rules were there before you chose to modify the car.

You CHOSE to ignore them and failed to plan accordingly.

Now you have to spend extra time and money to do what you should have done in the first place.

Test pipe with v-bands, cat with v-bands.

Ten minutes to swap them.

if the state didnt eliminate 97 gst's from normal obd2 protocall i would have passed with flying colors. to me thats getting shafted. and i tried again today. adjusted the injector dead time which cleaned up almost all of the no at 2000 rpm at 15.5:1 but co was wayy up. and actually not much time spent about 40min. over all and look at that, one brand new state inspection. $39.95, thank you. how much do three, 3inch stainless v bands cost? haha