Emissions Test fail, etc.

[Pete_BMR_z26]

First off, I have a Z26 with the 3.1 L V6 engine. I went for Inspection in NJ (where I live), and failed for Idle Emissions. My HC ppm was 312, and the standard HC ppm is 220. My high idle (acceleration) readings were well under the standard, and passed. After failing and reading endless forums, articles, watching Youtube videos etc, I figured I would try CRC Guaranteed To Pass Fuel system cleaner. I haven't tried it yet, however. After buying it, I decided to check the O2 sensor, air filter and such just to make sure everything was connected. What I found was a 3 inch slice in the air duct connected the filter to the intake. My guess is that this slice could be restricting air flow to the intake during idle (low pressure?) but due to a higher pressure at higher RPM, the slice wouldn't matter because enough air is getting into the intake. Again, these are all assumptions. Could this slice be enough to make me fail for idle, but pass for acceleration/higher RPMs? I've thought about Seafoaming to clean it out, etc. I'm just not sure what I should do. Obviously, I'd like to pass without doing anything major to fix it. My guess is that it is not the catalytic converter either, due to the 'minor' failure of only 92 HC ppm. Note- The car was running for about 10-15 minutes, then I drove to the inspection facility which is only about 3 miles away. Could the engine not have been hot enough? ANY help/suggestions would do. Thanks, I've been bashing my head in!

Again- Low Idle HC ppm was recorded at 312ppm, where the standard is 220 HC ppm.

[Money pit Beretta]

All that slice is doing is letting in unfiltered air. Can you give a little back ground? Like what plugs you are running and how old they are? Anything would be helpful.

Sea Foam down the booster should help some. It will sure help the engine run better, there is a lot of build up on a high mile engine.

[3X00-Modified]

HC is going to be an un-burnt gas issue as you've probably read online. What year is this car? And when was the last time it got a standard tune up like plugs and wires and such?

[Pete_BMR_z26]

Yeah I've read that it's basically just raw, unburnt fuel. I'm not exactly sure the deal with the plugs (which is something i read up on today during work, and will check out once I get home), but I know the lines look rather new. It's the 1995 z26. I didn't think to check the plugs, because the wires seem close to brand new. Basically, I bought it off a guy for $450 back in August, and have been working to get it back on the right track. It's at about 129k miles right now. So the slice shouldnt have any effect?

[3400beretta]

312 is really high. Don't forget, 220 is already a high reading, they allow you ALOT of leeway there. IIRC my 94's idle HC were in the 90s. What was your high idle HC reading? It should be very low, like less than 20PPM.

The slice probably isn't causing an issue, but you should seal it up none the less. I would look at possibly a sticky injector. If its not closing all the way, it would be dumping tons of fuel in at idle in one (or more) cylinders, causing your very rich condition. Also check your plugs and wires as Jon said, and then move onto the o2 sensor.

Posting ALL of your results can really help here.

[Pete_BMR_z26]

Oh so that IS high? (you know what they say about assumptions). Right now I have the slice patched up with some black duct and electrical tape, so that should be fine for now. As for the other readings, here they are:


Mode: IDLE - FAIL
GAS Reading Standard
HC ppm 312 220
CO% 0.64 1.20
CO2% 14.1
O2% 1.2


Mode: HIGH IDLE - PASS
GAS Reading Standard
HC ppm 54 220
CO% 0.48 1.20
CO2% 14.7
O2% 0.6

Also, about a month ago, I discovered my transmission cooler lines were leaking, so I had them replaced, along with the radiator (the lower line was seized in the radiator). The tran kept slipping going from idle to half way through first gear or so, then after 2nd gear it would be normal. Well that stopped once i had the lines replaced, until... on my way home from work today, it started happening again. It's extremely frustrating. Could this actually be a non/mis-fire of one or more of the injectors or anything to do with this? Once I get the car going, it's not a problem. It's the initial acceleration where the car just doesn't accelerate. At a complete loss.

[Pete_BMR_z26]

Bump!

[3X00-Modified]

We've given you some ideas... have you inspected anything else? Check fuel injectors checked O2 sensor? I don't know what your looking for really.

[weba]

I also just failed idle HCC, here the limit is 100 and I scored 120...

I have changed coils recently, plugs and wires are couple year old. Tried to tune it down to 25% idle VE, still get BLM of 100.. I think the injectors are leaking or something.. 3weeks to fix, or not allowed to drive anymore :O

[Pete_BMR_z26]

Just an update.. I went to take my car through inspection again yesterday (over a month since failing), and i PASSED! Since failing, i cleaned the MAF, cleaned out the throttle body/plate a bit, changed the oil, and put Guaranteed to Pass fuel cleaner in. I pushed the car a bit on my way there, trying to get the cat as hot as possible, and drove right into the station. I didnt have to wait at all. They checked for everything, and put my hood up this time. It was weird, but whatever. Just glad they didnt say anything about my duct taped air duct!

[3X00-Modified]

How did you clean a MAF on a 95 OBDI car? They don't have MAF sensors.

[Pete_BMR_z26]

What's the sensor that is hanging in/connected to the air duct?

[Money pit Beretta]

If it's the size of you finger it's the IAT. Inlet air tempature sensor. Now if it's metal and over three inchs around it's a MAF. A 96 would have a MAF.

Glad to hear that you passed. Do you think that the fuel cleaner did it?
If so then you have a bit more work to do.

[Pete_BMR_z26]

Ohhh okay then yeah it's the IAT. I've seen pictures of MAF's and just assumed mine was different.. LOL glad that's cleared up.

But I'm not so sure if it was the fuel cleaner or not. I put the cleaner in about 3 and a half weeks and a few tanks ago, so I'm not sure. The car was just sitting for over a year and a half when I got it, so maybe it needed a cleanout? I'm not sure. My oil was due for a change the first time I took it too, and the cat wasn't nearly as hot the first time either. Like I said, I was going about 65-70 the whole way to the inspection station, for about 12 miles. A lot of variables, so it's hard to say

[Money pit Beretta]

I'm sure the gas was not very good and that the fuel system needed to be cleaned out.
We will have to wait and see. Well if the cat wasn't as hot then it must be running better. I'd say there is still work to be done, but that will be later.