Failed Emissions at Idle. Any Ideas?

black143 · Apr 26, 2004

I just took my car in for emissions and failed the idle part on both the HC and CO2. I passed with flying colors on the cruise portion. Any ideas where to look? I have brand new injectors, spark plugs, cap, rotor, EGR valve, etc. Thanks guys.

jaackal · Apr 26, 2004

quick fix to just pass emissions would to be dump a couple bottles of isopropyl alcohol with little gas in the tank, you should pass

black143 · Apr 26, 2004

Yea that is a good idea, but whatever caused my car to fail is probably causing performance problems so I would like to get whatever it is fixed.

jaackal · Apr 26, 2004

it could be the timing but i dont know, mine 88lx failed for emissions so i just dumped some alcohol in it and retarded the timing back to stock and now its fine. i was running the timing at 16* advanced

black143 · Apr 26, 2004

My timing is at 12. I guess I could try the alcohol since I do get a free retry. I need to get it done this week though so thats why I dont want to mess around with it.

kevin2m4 · Apr 26, 2004

where can i buy isopropyl alcohol?

black143 · Apr 26, 2004

kevin2m4 said:
where can i buy isopropyl alcohol?

your neighborhood drug store

65ShelbyClone · Apr 26, 2004

If you use isopopyl, then get the highest percent you can find. Most is around 70%/30% alky/water, but I've seen as high as 90% alcohol. another option is denatured alcohol, which is ethyl(grain) alcohol with junk added so you cant drink it. That is probably higher than 90% alcohol and will do the same thing.

They dont test for CO2 here in CA(which is wierd since they're mege anal about everything else), so I dont know what would cause a high reading. The high HC means you're either burning oil or running rich. You didnt say if your new injectors are 19s or larger and I assume you dont have a cam since its not in your mods. All that comes to mind are iffy oxygen sensors.

black143 · Apr 26, 2004

The injectors are 19 lb. I havent had an oil change in 3000 miles and I forgot to get one before the test so I will be sure to get an oil change before testing again. I was thinking about O2 sensors since I've driven the car 70,000 miles and I've never changed them. I tried messing with my tune before the test (adjusting the idle screw and TPS). I got my car to idle around the right RPM but I could smell the gas so that sucks. I'm just going to take my car into an authorized emissions service shop and have them hook it up to their computer. It would be a lot faster. Thanks for the info guys.

Idwitheld-1` · Apr 26, 2004

black143 said:
I just took my car in for emissions and failed the idle part on both the HC and CO2. I passed with flying colors on the cruise portion. Any ideas where to look? I have brand new injectors, spark plugs, cap, rotor, EGR valve, etc. Thanks guys.

HC = run rich.

Return your timing to 10 deg. BTDC.
It is possible your 02 sensors are at fault, any codes from the EEC?
Can your bring your Fuel pressure down a touch? (2 psi or so)

Is your smog pump hooked up? Are you pushing air into the cats?

black143 · Apr 26, 2004

Idwitheld-1` said:
HC = run rich.

Return your timing to 10 deg. BTDC.
It is possible your 02 sensors are at fault, any codes from the EEC?
Can your bring your Fuel pressure down a touch? (2 psi or so)

Is your smog pump hooked up? Are you pushing air into the cats?

I am getting an EGR code from the EEC but the EGR is obviously working because the EGR isnt running at idle or WOT and I passed with flying colors at the cruise, which is when the EGR is functional. I dont have an AFPR so I dont know how to bring it down. All my smog equipment is hooked up and should be functional. Why would I lower my timing when a higher timing makes a car run more lean (or am I confused)?

kevin2m4 · Apr 26, 2004

if its the 5.0 just take off the 2 8mm egr bolts and clean out the egr channels
mine were clogged up hardcore

Idwitheld-1` · Apr 26, 2004

black143 said:
I am getting an EGR code from the EEC but the EGR is obviously working because the EGR isnt running at idle or WOT and I passed with flying colors at the cruise, which is when the EGR is functional. I dont have an AFPR so I dont know how to bring it down. All my smog equipment is hooked up and should be functional. Why would I lower my timing when a higher timing makes a car run more lean (or am I confused)?

I think you've hit on the problem. Your running 12* timing to compenste for a rich condition. In some states they check your base timing. Plus you mentioned, "Yea that is a good idea, but whatever caused my car to fail is probably causing performance problems so I would like to get whatever it is fixed." I assumed you would want to return to a known point for the test (as your tested against emissions for the year of your car)....why complicate it by running advanced?

If your mass air, clean the sensor (carefully). I would suspect something is wrong with your smog control/cats, O2 sensors. How badly did you fail?

wisconsinboy · Apr 26, 2004

ive heard if you know some people at a junkyard or anyplace that takes in wrecked cars theyll sell you the sticker that says you passed that test(granted they know you well and know your not the po) just wondering if that was true or not i live in wisconsin i dont feel the need to know about emmisions laws

Scott W · Apr 26, 2004

I agree with the others, you should reset timing to 10 degrees. I ran a pre-test on my car and i was failing badly, as the pre-test ran the guy started decreasing my timning and all of the red boxes (failing) began turning green. I don't know how low he eventually dropped my timing, but I passed, and the car ran fine after. I then got it reset to 14 (where I was before)

by the way, i have 285,000 kms on a stock 89 5.0L. I have all 4 cats punched out and I still passed with just the timing decrease!!

black143 · Apr 26, 2004

I've had my timing at 12 for quite some time now. I cant remember if I set it before or after I had my emissions done the first time since it was done two years ago. I just cleaned out my EGR valve and all that stuff.

My injectors were leaking pretty bad before (thats the reason why I replaced them) so that could have done something to the cats. I'm starting to think it very well might be an O2 sensor. I advanced my timing to give me some power, not necessarily to fix a rich condition.

Unfortunately, my car is SD which makes it much harder to tune.

Why is it you'd pass by retarding your timing? Please explain this to me.

I passed pretty bad.

Cruise HC Limit: 160
Cruise HC Emissions: 88 (Pass)

Cruise CO Limit: 1.1
Cruise CO Emissions: 0.2 (Pass)

Idle HC Limit: 220
Idle HC Emissions: 409 (Fail)

Idle O2 Limit: 1.2
Idle O2 Emissions: 1.67 (Fail)

Any other information before I take it to the shop tomorrow would be great. Thanks guys.

Rains · Apr 27, 2004

its the idle air control screw

you have exactly what mine had...... take it to the shop and have them check it out

also... make sure base timing it at 10*

black143 · Apr 27, 2004

I dont have a timing light so I'm going to have to have them adjust the timing. I'm still confused as to why lower timing will make it leaner.

Mustang90GT50 · Apr 27, 2004

I failed emissions four times with my car and finally ended up going to a hardware store around town and buying what I beleive was one quart of denatured alcohol to about a 1/4 tank of gas and passed easily. I think the final numbers were about 17 out of 150 and 34 out of 225. Anyways its another idea.

Failed Emissions at Idle. Any Ideas?

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