Since this only doing this at idle what temp is your car running at? Everytime I went for smog in my 94 it would fail because my temps were set at 160, once i removed the program for my fan to turn on at oem specs the car would pass smog. By looking at your sig my 94 is setup just like yours.

 

Generally if you only fail on HC's its a fair chance you have a bad or failing cat. A rich condition will usually cause the C0 % to fail as well. Easeiest way to check the converter is with a temp gun. The convertor should noticably hotter at the exit of the cat then at the front.

 

As I said earlier, the car had been driven for 30 min prior to me getting it smogged, all 4 times I have had it tested so far. Temps were in the 200's. The cat is basically brand new with maybe 5000 miles on it, so I'm pretty sure that isn't the problem.

I gave the whole car's wiring a good looking over today and checked all the connections on everything. Every spark plug wire got inspected for melts/burns. Still haven't found any other possible sources of the problem. I'm thinking about ordering up that FPR soon and putting everything together and seeing what happens, cause its killing me to watch my car sit and rot during this perfect summer weather here in California. Anyway I'll let you guys know what happens. Thanks.

 

What rpm does it idle at and have you messed with any of the individual cylinder fuel trims? What i usually do is set all the cyl fuel trims to 1, and then use egt sensors or a temp gun and take readings then make minor adjustments up to 1.025 , 1.05.. etc until the header pipes are all the same temp. That will usually knock down hc emissions quite a bit at idle. There isnt really any other magic way to lean it at idle out unless you stick it in open loop or do some other things to the tune.

However, if you're idling at 650 rpm to make it lope that aint gonna get it, speed the idle up to the point where the lope disappears and your uhc content will go down in your exhaust. You could also check your o2's out with datamaster. See if one side has alot higher blm than the other, then trade sides with the o2 sensor and see if the high trims follow the sensor.

 

WS6T3RROR:
It idles at 850rpm. It does have a pretty good lope to it for being a small cam, but it should have no problem passing smog. I haven't touched ANYTHING as far as my tune/pcm. I left that all up to PCMforless. Even though they did a great job, I kinda wish now that I had done it myself, because I think I would understand certain things a lot better.

My o2's are brand new, however I do remember the numbers looking a little bit screwy in datamaster. However, I didn't really pay that much attention because o2mv's are normally all over the place. I'll definitely take a close look at them in the morning. Maybe I can narrow my problem down to one side or the other. Thanks for the idea!

 

Note: I realize this thread is pretty old, however I would like to keep everything in one place for the sake of reference.

Update:

Bad news. After checking my injectors for leaks/drips with the key on, engine off, I then installed a brand new AC Delco FPR, due to the fuel smell in the vacuum hose attached to the old one. I re-adjusted my valves as well because I had one or two slightly tapping. The car was running smoother then ever. I also made sure to change the oil the morning before the test, to get rid of all the HC that had probably built up in the old (1500 mile) oil. Took it out for a 15 minute drive and made sure to get everything hot, and then arrived the smog shop, and the guy said he "could smell the hydrocarbons from inside the office". Even though the car smelled perfectly fine to me, this was definitely not a good sign of things to come. Anyway, long story short, the car failed WORSE then before. Hydrocarbons were in the 350-360 range (opposed to 220 the last time I had it checked with the supposedly bad FPR), passing is below 100, CO was in the 13.00-13.6 range (passing), and Nox isn't being tested. But seriously WTF!!!! WORSE?!! To make matters worse, the old man was pissed at me and told me I was wasting shop time (1pm completely deserted??), and he didn't want to see the car again or he would tag it as a gross polluter. What a DICK.

Anyway, I'm really at my wits end with this car, everything seems to go wrong with it. I guess I am going to be checking out the new FPR after I get off work today, maybe I got a bad one?? When I had everything apart this weekend I checked every system that could possibly relate to elevated HC. Charcoal canister isn't saturated, doesn't even smell, lines aren't clogged, cracked, or spongy. The lines coming off the EVAP solenoid are good. PCV is ok, the hose was a little cracked up, so I made sure to wrap that tight with electrical tape until I can find a replacement. I really didn't want to have to get a special smog tune for the car, considering I've read literally hundreds of posts on here and other places (good thread on CA smog cams http://www.impalassforum.com/vBullet...ight=Cams+smog) saying the hotcam should have no problem passing. My car likes to defy common knowledge though, so I'm not suprised lol. Well anyway its back to the drawing board on this one. Feel free to chime in. Thanks for all your help so far guys.

 

Try seafoaming it!

 

Seafoamed it good when I bought the car, but it has been 10 thousand miles or so since then. I was thinking maybe running some injector cleaner through it or something. Honestly, the last thing I could think of that could possibly be contributing to this, is the injectors. Maybe I just need to pull them and send them off to be professionally cleaned and flow tested. They looked clean and undamaged when I looked at them over the weekend, but obviously there could be something internal that I'm not seeing...

 

Looks like we have the same HC limit in Sweden and California, 100 @ idle. The first time I did the test after putting in a non emission friendly cam I got 2500!! After giving the car hell for 4 laps around the emission building it went down to 450. After swapping cam: 50

 

Update:

In the process of working on it right now. Datamaster is indicating that the (left?) side of the engine is running rich. As soon as it went into closed loop LTerm numbers immediately dropped into the 117 range for the left side, whereas the right side at idle is a constant 128. I am sort of confused about which side is which in Datamaster. Data that is displayed in the left hand boxes is for the left hand (drivers) side of the engine, correct? Anyway, this is probably a sign of an injector problem I am guessing.


Also, the FPR vacuum hose seems to have a STRONGER gas smell then before, but maybe that is left over from the leaky old FPR. I'm in the process of soaking it in water and mild soap to try and get it as clean as possible, and I will put it back on and see what it smells like after driving it. Does anyone know which side of the engine would be affected the most by a leaky FPR? I am assuming the right side.

 

Haven't made too much progress tonight, however I found a good thread about one side of the engine being richer than the other (https://www.camaroz28.com/forums/sho...d.php?t=622318). I am going to try what he did and swap the left side injectors for the right side, and see if the problem follows. I will update as soon as I have more info.

 

Well, I swapped the left side injectors for the right side injectors today. Left side is still running rich. I drove it around to get the o2's nice and hot, and at idle, left side LTerm is 114, and right side LTERM is 130. I am going to swap the left side o2 sensor with the right one once the car cools down, and see if the rich conditions changes sides that way.

 

Update:

Swapped the left side o2 sensor with the right one. Still no change in the rich condition on the left side. Next up, I am going to pull the drivers side plug wires this week and test the resistance, as well as change out the spark plugs for the drivers side. Thank goodness its the drivers side I am having this problem on

 

Update:

Well, I finally got done with my LS1 brake swap, and at the same time I took the opportunity to pull the drivers side plugs, and wires and examine them. All of the plugs look normal, however, cylinder one plug definitely has more tannish color on it then the other ones, but from what I have read this is normal?? I checked the spark plug wires for any burns, all of them were clean and looked almost brand new. Tested the resistance on the wires, and it was normal. Now I am really at a loss. Not to mention I discovered a nice new coolant leak that just started since I began working on this car over the weekend, and found out my pinion seal is leaking. Just when I thought my car was in great condition for being a 94...

I am thinking about making a datamaster log and posting it for people to take a look at it. Any ideas??

 

Did you figure out your coolant leak? That could be snuffing the combustion causing the high HCs.