Just failed emissions, CO level was 4.63 at idle and 2.74 at 2500 rpm. O2 level also high. The smog guy has had camaros and he though MAF is bad and is loading up with fuel, he also thought it was missing. It has run great after just completed head gasket job, very smooth. I just never sit and idle so I have not had this problem...any ideas would be appreciated

 

We need more info. Was the CO in PPm. What is the standard you need to meet? How about HC's? and do you need to pass a NOx standard. Is your car modified? All emmisons equipment still in place?

 

I hope you tested it warmed up...

 

The CO is a percentage, max is 1% mine is at 4.63% at idle and 2.74% at 2500 rpm

The HC was 223 ppm, the max is 120 at idle, and then at 2500 rpm it went down to 40 ppm on a 140 max

The O2 was 2.6% at idle and 3% at 2500 rpm, I don't know what passing is but he said that failed...

The CO2 was 10.10% at idle and 10.3% at 2500

all emission equipment in place and funcitonal

car is in a good state of tune and timing is correct

only mods are screens removed (which worries me now) coolant bypass, 170 degree stat, and catback exhaust

The car was warm enough to kick on the fan

 

If it is missing, that would be the easiest problem to cure, and a good place to start.

 

I really don't think the car is missing, it is like glass normal driving, for some reason at idle it is getting loaded up with fuel, or running rich, which makes the idle a little rough, any ideas?

 

It shouldn't run rich at idle when it warms up. The O2 sensor should be on line by then, in closed loop and pulling the fuel back to where it needs to be to hit stoich (14.7:1).

Bad O2 sensor, modest vacuum leak or an injector that isn't working properly, perhaps.

Also, even a slight ignition miss will cause HC to SKYROCKET. I had a 305 TBI engine that had one bad plug (found out later). It ran just fine, never a problem with it and no obvious miss like running on 7 cylinders. I didn't find this problem until AFTER I put on a new cat (which didn't fix anything but put me over the financial limit on how much they force you to spend to attempt to fix an emissions problem). With 1 fresh replacement plug it passed perfume out the tailpipe.

 

This is where it gets confusing, the guy checked vacuum and it was good, I just had injectors cleaned, new O2 sensor.

I will go back and put new plugs in and see if that helps, the plugs I have now are bosch plugs that were in it when head gasket was failing, also I am going to try stock thermostat...

 

What is the state of the converter itself?

 

exterior is good, the inside of it looked fine when installed the cat back, it does have 150K and I am guessing it is factory converter, it passed right when I purchased it and I only put on 8,000 miles or so, but everything on that car was bone stock, is there any other test for the converter, or a cleaner?

 

Looks like it's running rich, high HCs and high CO. You want to get it hot to burn off the excess fuel. Start by putting the stock 195 thermostat back in. Be sure your air filters are clean and make sure you have a good hot spark, check out your plugs, plug wires , cap and rotor, if any of these are worn replace them. Before you go for the test get it hot. I rev mine in line waiting for the test. Lastly one trick I have used is to put alcohol in the gas at a 1 to 10 ratio. My car ran like crap but it passed, I can't explain why. The good news is that you don't have to pass a NOx test because getting it hot like this would send your NOx emmisions through the roof. As for the MAF screens I took mine out too, but put one back in on the inbound side to smooth out the flow. My car ran smoother after putting it back in. Think of it like taking the screen on a bathroom faucet out, the water sprays all over. With the screen it flows in a more consistant manner, which should give a more accurate MAF reading. I just put some metal window screen over the in side and held in place by putting it into air cleaner tube and the clamp holds it.

 

As far as the miss goes... if there is one.
After you check the ign system and the injectors, a possible source of that problem could be a slight coolant leak into one of the cyls.
There can be enough coolant leaking into the chamber to "put out the fire" at idle, but then as the rpm increases the leakage becomes minimal and the miss goes away.
Possibly a bad gasket or a pre-existing crack in the head could be the source.

 

I went and checked for codes, showed code 42, what is it? I also bought some pass emissions stuff which is probably just alcohol, new plugs, 195 stat, and pcv valve, all goes on tommorrow

 

code 42 is electronic spark timing, or EST. did you check or set the timing in the last few days? if so thats where it came from, if not then you have a problem some where.
clear it & then take it for a drive & see if it comes back.

your rich for some reason. even without a cat your CO should be lower than what it is.
do you have a way to look at the data from the ECM?

 

the timing was just checked by the smog guy, I don't have a way to check the ECM, what do you need to do that?

 

I put plugs, PCV valve, thermostat, and pass smog stuff in the tank. The idle fluctuates from 500 to 750 at times. I also had to add coolant and this after a head gasket job, I don't know if I filled totally after head gasket, how can I get the idle right?

 

If there's a coolant leak into one of the chambers, there's a test that can be done. Most radiator shops can do it, I think it tests for hydrocarbons in the cooling system or something like that. That would surely cause problems.
Coolant on your O2 sensor will foul it, throwing everything off.
It would probabaly be a good idea to do that test to see if there's a leak.
Considering you just had your heads off, there's a possibility.

 

You will get a code 42 if you don't reconect the EST wire after checking timing. It is a tan and black wire on the passenger side of the engine compartment near the firewall. it has it's own black connector. When it's disconnected it takes the computer out of spark advance. So your ing. timing will be 6 degrees retarded at idle from what it should be and it won't advance as it should at higher RPMs

 

smog guy thought what i fixed would not do it, he said go test the cat and the cat was fine

he thought there was a miss too, i don't know what to look for, i checked all the plug wires and put in the new plugs

when i started the timing was above the scale advanced like 14 degrees and then it would move around while it idled, is the computer moving the timing?

 

second, what is the burned wire for?