numbers from failed emissions test...what should I try for next time?

CaifanSC

SCCoA Member
I took my 95 to emissions a few weeks ago and it failed. I wanted to give try two today or tomorrow, but I wanted to run the numbers by you guys to see if there is anything I can do to better my chances. I have a slight suspicion that the test wasnt done right the first time (they had to try 3 times:rolleyes:)...but i really dont want the car to fail again.

The car has a fresh oil change, the fuel pump, plugs and wires are about 4k miles, all filters are also about 4 k (fuel and air) as is the PVC valve (stock motorcraft).

Here are the numbers:

HC actual- 1.1741 cutpoint: 0.9000 Failed
NOX actual- 2.2867 cutpoint: 2.1000 Failed
CO actual - 10.6109 cutpoint: 20.000 Pass


I heard about disconnecting the spout connector, which I will probably try. Any other suggestions?
 
whats done to the car? I assume you still have cats? Believe it or not that pass in a can stuff works. The spout will remove timing but may not help and may hurt depending
 
My 92 was able to pass emissions for several year in PA. Imagine my surprise when I got the custom exhaust system installed and found out that either the previous owner hollowed the cats or they fell apart on their own somewhere along the way. Passed emissions the next year after the install too. Nice to know I no longer have to worry about that stuff here in MI.
 
Is your test done at idle or on a dyno? If it is at idle I suspect a vacuum leak. If it is done on a dyno, it is more likely that the cats were not hot enough or they are hollow or non-functional.

Pulling the spout may very well generate a "pass" but you'd be better served to figure out what the problem is if you can.
 
thanx for the replies guys

the exhaust system is pretty much stock. The previous owner installed custom downpipes and new cats..im not sure if they are hi flow, but they seem stock-ish. They look to be pretty new and are not even corroded, they still have a shiny bluish-purple glow to them. The rest of the system is stock. The only real mod to the car is a cold air intake.

as far as a misfire..well i dont really feel anything wrong with the car. WHen i got it, i had to diagnose a no-start condition and in the process i changed the entire ignition system (cam sensor, crank sensor, coil pack, wires, plugs, DIS) i think i changed the computer. The same with the fuel system, fuel pump, filter, pressure regulator, i checked all injectors and replaced some that had the pintle cap damaged. In every day driving, the car doesnt feel to sputter in acceleration or idle. :confused:

The test was in the dyno.

Damon, where do i get that pass in a can thing? Is it something i can find in the part store?

Any other suggestions?
 
Pass in a can, can get at parts store.

I would say the cats are no good, If the engine is stock. Does it still have egr on it?

The car I just got didn't have cats or egr so i installed all that stuff and it passed great.
 
Sounds like the car has an issue. Maybe the previous owner changed the cats attempting to resolve an issue that was pre-existing. Could be the new cats got overheated and aren't working any more either. Just a thought. How does the car run? Good power?
 
well that no-start condition when I first bought the car ended up being the last thing i checked...the harmonic balancer. So taht was replaced.

Since the balancer was fixed and with all the parts replaced, the car runs great...good power evenly through the power band, great idle, no hesitation or surging at all. That is why i was surpriced that it failed emissions really.
 
I'm going to go out on a limb here and make a guess. Original owner had failed cats due to a bad harmonic balancer. Replaced cats. New cats failed due to harmonic balancer. You fixed balancer problem, but new cats are also failed. The coloring you describe isn't entirely abnormal, but it does point to extremely high temperatures. Drop the exhaust and check for melted cats.
 
Well, the cats may in fact be bad, but there are so many stories of people passing emissions with no cats at all ... my uncle did it ... that I think it probably points to some minor problem with the car. Not necessarily something big, but there could be something.

Or the test was done wrong like Dave said - the car wasn't warmed up enough for the cats to function. Especially if the cats have been moved downstream from their original location ... they need to get hot to work.

The vacuum leak sounds like a good possibility to me. The PCV system can easily leak unmetered air. The crosstalk tube between the plenums is often work out. Also the nest of vacuum lines hiding behind the brake booster. It's probably worth checking that stuff in any case. If that doesn't turn up anything, then you could move on to checking the cats.
 
well, the good news is that I passed this time. :) I'm leaning more towards the first test done wrong.

On my way to the test I stopped to drop off some oil and ofcourse something had to happen...some idiot backed into me and hit my front bumper...so needless to say I was pissed off. SO i ended up not goign to autozone like I had planned to get that pass in a can thing, i just went straight to the station. I get there, they tell me I have to pay $135 for late fees..i go to the ATM to get the money, but make some phone calls...long story short...voila! I test, I pass and didnt pay a thing :D. I also forgot to disconnect the spout connector, so I literally did nothing different than the previous time it was tested except for an oil change. Well that and i guess i heated the cats a bit more this time since i stopped by the ATM.


Now i gotta figure out what to do about the A hol that backed into my car :mad:
 
I'm with dave on this one

I'm a California driver and deal with smog all the time (hate it)...and my buddy owns a smog shop (love it!)...hey says most fails are from impropper testing and if one shop fails you go somewhere else...but I'm with dave, if you're sure the cats are aftermarket, you might have a cat issue. Plus I believe if you have NOX failure & HC failure it is usually your cats.
 
im thinking of doing a clutch job on the chameleon so the front part of the exhaust will have to come out...i'll check the cats then to see if they're messed up or somethin.


Chris,

thanks for holding that for me! I ordered the sunroof seal a couple days ago so I'll definatelly get on to picking that up from ya bud :D.
 
Just found out the cam sensor syncronizer was 90* out and I passed with flying colors. Fixed that last nite and it pulls alot better now.
 
Ironically, I just failed an emissions test of my own. My HC and CO readings were very good ... about 0.38 out of a maximum 1.1. But my NOx readings were 4100, over the maximum of 3600. I was disappointed, but not completely surprised, as I squeaked by my last test with 3591 out of 3600. I don't know if the shop warmed the car up correctly, but I am guessing that they probably did as they are a good shop in general.

Since the HC and CO were great, I figured the high NOx was an isolated problem. Since it only forms when combustion temperatures are high, I retarded the timing as has been suggested before by others on this board. I figured I was close enough to the limit that I only needed a little bit of timing pulled, so I only pulled the octane adjust plug to remove 3 degrees of timing. I also took the step of adding some gas line antifreeze to the tank. This is apparently useful because it contains methanol and has a combustion cooling / quenching effect. (Correct me if I am wrong.) I added 4 bottles of HEET to 3 or 4 gallons of gas, so it only cost me about $8.

I also replaced the O2 sensors as they were old and I thought it would be a good idea to demonstrate to the testing mechanic that I was trying to fix it and not just sneak through.

So, I went back and retested ... and I passed! NOx came down to 2680 out of 3600, and HC and CO stayed almost identical ... about 0.41 out of 1.1.

So, that's my story. Maybe it can help someone else with this problem.
 
Back
Top