Help tuning for emissions

Posted By: midnite360

Help tuning for emissions - 03/12/14 03:03 AM

Engine is a 318... Do I always have trouble passing the HC And CO at Idle... What are your guys tricks... Timing is at 13* right now, was thinking I should drop it down to 10* lean out the mixture screws... What do you guys set your idles at? Is it better to have it idle at higher RPM's or Lower?

Posted By: Dcuda69

Re: Help tuning for emissions - 03/12/14 03:16 AM

Normally retarding timing, leaning out the screws and increasing idle speed helps,however if you go too lean it will develop a lean misfire which will drive HC through the roof. Need LOTS more info such as..what car,what emisssions equip(AIR,egr,converter?)Remember they made 318's for a long time!What gas failed(or has failed)What other gases are tested?Is it ONLY an idle test or do they check it at 2500 rpm or run it on a dyno?What are the limits allowed? Engine condition?

I can't believe they're still tailpipe testing anything..we dropped it years ago!

Posted By: midnite360

Re: Help tuning for emissions - 03/12/14 03:25 AM

318 in a 69 barracuda... Only equipment required is a PCV. I failed idle today pretty bad... Didn't mess with anything just went for it to see where it was at.

MY UNDER LOAD RESULTS
HC 182 Standard is 450 PASS
CO 2.40 Standard is 3.75 PASS
My IDLE RESULTS
HO 712 Standard is 450 FAIL
CO 6.84 Standard is 5.00 FAIL

Posted By: Dcuda69

Re: Help tuning for emissions - 03/12/14 03:31 AM

Quote:

318 in a 69 barracuda... Only equipment required is a PCV. I failed idle today pretty bad... Didn't mess with anything just went for it to see where it was at.

MY UNDER LOAD RESULTS
HC 182 Standard is 450 PASS
CO 2.40 Standard is 3.75 PASS
My IDLE RESULTS
HO 712 Standard is 450 FAIL
CO 6.84 Standard is 5.00 FAIL

Definitely rich at idle..6.8%

Try to lean it out with the screws and bump idle up a little....should bring CO and HC down. I'm assuming this thing has a stock style cam..what carb/intake? Make sure the oil is clean and not polluted with fuel(pcv will pull the vapors into the intake and make it "rich")

5.0% CO is passing..lol....why even bother to test?

Posted By: midnite360

Re: Help tuning for emissions - 03/12/14 03:49 AM

It has a Wiend Stealth and an Eddy 750 (I KNOW TOO BIG) I no bigger then the one I replaced and passed with flying colors! What should I set the idle 850-900 in drive? Stupid that I need emissions for a 69.... Arizona is worse then California!

Posted By: Dcuda69

Re: Help tuning for emissions - 03/12/14 03:55 AM

Big carb! I would bump the idle 150-200 rpm over where it's at. Adjust the mix screws for"lean best idle"(readjust idle speed if necessary) and give it a shot. How many tries do ya get?? We used to get 3 here when we did tailpipe testing

Posted By: 383man

Re: Help tuning for emissions - 03/12/14 05:50 AM

I was going to say it looks rich as if you can lean it down without the lean missfire both HC and CO will come down. But it looks like Dcuda69 has already told you what to do so I would take his advise. Good luck , Ron

Posted By: midnite360

Re: Help tuning for emissions - 03/12/14 06:18 AM

Thanks guys...Will I be able to notice a lean misfire?

Posted By: Cab_Burge

Re: Help tuning for emissions - 03/12/14 07:54 PM

Go buy a gallon of Coleman lantern fuel(white gas) and put it isn before driving the car to the test staion, one of the old tricks we used in CA to pass emissions tests when I lived thier

Posted By: midnite360

Re: Help tuning for emissions - 03/12/14 07:55 PM

Ok guys I did some tuning and I am very close CO is still way to high though My idle reading are HC 534/450 my CO is 6.75/5.0 I am going to go through one more time after more tuning if I fail I'll Ty changing the oil it may be saturated with fuel from running rich. They haven't checked under hood should I disconnect the PVC?

Posted By: midnite360

Re: Help tuning for emissions - 03/12/14 08:17 PM

Wow ok 3rd time through I passed all idle tests but now I failed CO underload here are my new stats
HC loaded 234/450 Pass
CO loaded 8.19/3.75 Fail
HC idle. 255/450 pass
CO idle. 1.46/5.0 pass