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Old 05-17-2007, 06:13 PM   #1
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Wink Guys, help me pass my Emissions test, please

Hey Guys,

Here is the quick story.

Put the car away last fall. (should of really tested it then )
Got it out of storage this week.
Put on maybe ~500kms this week
Filled up the tank (still had 1/8th of last years gas when filling it up).

Had it tested today and just failed, here are the readings

@40kmh
HC ppm 78 limit 83 reading fail
CO% 0.44 limit 0.19 reading pass
NO ppm 0907 limit 862 reading pass

So the HC ppm was just too high,

Does anyone know what can bring this down.

I really want to have it retested tomorrow so i can get serious about installing the Turbo kit....

I am thinking of filling her up with regular and adding some rubbing alcohol
I know this helped my Supra Turbo pass last fall...

Thanks for your suggestions
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Old 05-17-2007, 06:28 PM   #2
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http://www.autobarn.net/ch05063.html

Who knows? This and a fresh tank of gas?
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Old 05-17-2007, 06:28 PM   #3
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Car is pretty much stock (engine wise) right now...
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Old 05-17-2007, 06:36 PM   #4
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New plug wires, quality plugs with the right gap and 85/87 octane fuel rather than premium.

High HCs are usually a result of misfires. It can also indicate a rich mixture, but usually this brings up the CO emissions as well, which doesn't seem to be the case.
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Old 05-17-2007, 06:52 PM   #5
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My protege LX would fail HC - backed the IGN down to 2* and it'd pass no problem. Just put it back to the 14* after the test so it was drivable again.
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Old 05-17-2007, 07:46 PM   #6
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That seems like a band-aid. The e-test is telling him that his ignition system is malfunctioning. Why not just fix the problem and end up with a better overall running car? There's no flippin' reason a stock Miata should fail an e-test unless it's not running right. I'd get the car running properly before I turbo'd it anyway.
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Old 05-17-2007, 07:57 PM   #7
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Because that's exactly what he asked for (not fixing his problem) and it takes five seconds to do. Means to end pal.
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Old 05-18-2007, 09:52 AM   #8
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Did the cat cool? Sometimes if the car has been sitting for too long before the test the cat, and the rest of the exhaust is not hot enough. Normally, I will run the car, get it nice and warm before going to the e-test.

Although, last year, they made me take it twice.... since... the base idle was too high.

Dave,
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Old 05-18-2007, 10:09 AM   #9
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failed HC = rich.

lean that **** out.

Quote:
What causes high HC (hydrocarbon)?High HC is caused by incomplete combustion; in other words, the air and fuel that went in to the combustion chamber was not completely burned, now the unburned fuel has ended up in the tailpipe. Problems that can cause incomplete combustion include:
  • An ignition misfire. If a spark plug does not spark, the air/fuel mixture in the combustion chamber does not burn and then goes out the tailpipe.
  • Incorrect air fuel mixture. If there is not enough fuel in the combustion chamber to ignite, the fuel that is there goes out the tailpipe.
  • Low compression. If the compression is too low the air/fuel mixture will not ignite and the unburned fuel will go out the tailpipe.
  • A bad catalytic converter. The converter lives in the exhaust pipe and burns unburned gas as it passes through.
One grassroots solution: A trick is to buy a gallon of denatured alcohol, pour it in, then fill up the tank with premium. You can find it at any home depot in the paint dept. This will cause your car to run lean and pass the test. Drive it carefully until you empty the tank, then drive normally.
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Old 05-18-2007, 11:25 AM   #10
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Quote:
Originally Posted by Braineack View Post
One grassroots solution...
I can't believe you'd offer up some hack fix for his problem rather than find a proper solution!
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Old 05-18-2007, 11:29 AM   #11
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I did a google search to find the proper definition of high HC....that's was a solution givin by someone when I was searching...i thought it was cute.
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Old 05-18-2007, 12:21 PM   #12
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HC failure is typically more consistant with ignition problems rather than air/fuel problems. Air/fuel problems can cause missfires but a rich air/fuel ratio is almost always accompanied by increased CO emissions.

Rules of thumb:

Failed HC: Ignition > Air/Fuel > Cat
Failed CO: Air/Fuel > Cat > EVAP (saturated filter)
Failed NOx: EGR malfunction > Overheating > Ignition
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Old 05-27-2007, 10:38 AM   #13
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Thanks for the tips guys,

So I ended up filling her to about a 1/4 tank with regular and added some rubbing alcohol and failed the damn test again

the HC actually went up so I dont know if i believe in the alcohol thing anymore...although it did seem to work on the supra turbo??

Anyway here are the readings this time

HC LIMIT 78 READING 95 FAIL
CO 0.44 0.19 PASS
NO 907 834 PASS

I dont know what to do, I really dont want to put any money into something that will be swapped out soon anyway, like a cat., I plan on installing the turbo and getting full exhaust soon...
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Old 05-27-2007, 11:41 AM   #14
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hi hc and hi nox
Did you check your plugs and wires?

Also, as suggested earlier, retard timing. You can do it in the parking lot before your turn. I've had to retard timing on a OTM so much to get it to pass, that the motor was weak to the point where it was tough to drive the car up on the dyno. But it got up, ran, and passed.

You're sooo close to passings it's silly.
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Old 05-27-2007, 11:42 AM   #15
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I always beat on my car a bit before an emissions test..... get the cat nice and hot, run premium with some of that "garunteed to pass" stuff, and I've never failed
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Old 05-27-2007, 01:11 PM   #16
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Quote:
Originally Posted by Ben View Post
hi hc and hi nox
Did you check your plugs and wires?

Also, as suggested earlier, retard timing. You can do it in the parking lot before your turn. I've had to retard timing on a OTM so much to get it to pass, that the motor was weak to the point where it was tough to drive the car up on the dyno. But it got up, ran, and passed.

You're sooo close to passings it's silly.
Thanks Ben,

The night before the test I checked the plugs, they looked like brand new, but were ngk bkr 5e's, i bought some 6's the other day that i think I will install before my next test...couldnt find the 7s that i wanted for after turbo install but hopefully 6 will be ok...

Also the wires seem to be in good condition

I tried to find the marking on the pulley but ran out of time so wasnt able to change the timing before the test. I will make sure that i find the mark and retard timing this time though.

Thanks
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Old 06-07-2007, 11:44 PM   #17
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Hey guys so I failed the E test for the 3rd time
Hoping you guys can give me some more ideas.

Here is what I did just before the test:

Changed the spark plugs to new NGK "6" (had 5's)
Adjusted timing back to 6 degrees (was at 12)
Changed fuel filter (did this on both of the Miata's)
Changed the O2 sensor (new bosch unit)
Reinstalled my original PCV as I think the new one may have been bad (the new one let more air pass both ways than the old one)
Just changed the oil and filter

Here are the readings on my 3rd attempt

at 40 kmh
hc ppm 78 limit reading 88
co % 0.44 limit reading 0.24
no pm 907 limit reading 595
2281rpms at 40kmh


curb idle
hc ppm 200 limit reading 198
co % 1 limit reading 0.46

I really wanted to tell the guy to drop it a gear to get the revs up, was 2281 too low for the 1.6?

The shop owner was telling me to look into the PCV or Mass air flow??

One thing that i did not mention to you guys yet is that i checked the compression the other day and noticed that the compression was low on #3

I had 175 on 1 2 4 but 3 was at 115-120psi

I really didnt even want to think about it but I would assume this could be a big factor in the high unburnt fuel readings?

The car runs and idles well, also there is good power on tap...

I did a wet test and it looks like the bottom end is alright.
I did a quick leak down test but need to spend some more time pinpointing the exact issue.(hopefully this weekend)


I truly doubt the problem would be due to abuse as I bought the car from a 75 year old guy who followed maintanence to a tee and the car was a bit of a garage queen. Probably would have been better if he did run the crap out of it....

Can I start by trying to remove any carbon build up?
What is the best way? Water?
Any other tests or sensors to check?

I think the next step may be to remove the head and have it rebuilt...this is really screwing up my turbo install plans..I really want to sort this out so i can move on...

Any more tips or thoughts are appreciated



Thanks
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Old 06-07-2007, 11:49 PM   #18
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Have you tried a new cat? If yours is old, a new cat might just get you to pass. Probably only a expensize as what you've already done. You can get a Magnaflow (catco) "high flow" cat bolt-in for ~$75 shipped.

Oh, and if you haven't put many miles on it since bringing it out for the season...drive it! Put some miles on it in "demanding situations."
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Old 06-07-2007, 11:59 PM   #19
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Quote:
Originally Posted by Atlanta93LE View Post
Have you tried a new cat? If yours is old, a new cat might just get you to pass. Probably only a expensize as what you've already done. You can get a Magnaflow (catco) "high flow" cat bolt-in for ~$75 shipped.

Oh, and if you haven't put many miles on it since bringing it out for the season...drive it! Put some miles on it in "demanding situations."
Thanks,

I am thinking of swapping exhausts from my wife's Miata. Her muffler is starting to go but i believe her cat was done last year. My exhaust is in mint condition and i plan on getting perf. exhaust once turbo anyway...If I would get a magnflow cat like you suggest i guess i could use it on my perf exhaust...nice - where can i pick one up? do you happen to know the size or model #?

Do you think the compression issue should be addressed before turboing?

I am sure it does, so I may redo the head and swap the cat. I bet it'll pass then...

I have put on about 2000kms before the test, i do a lot of hwy too.
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Old 06-08-2007, 12:07 AM   #20
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I don't believe the direct-fit magnaflow cat is big enough diameter pipe to use effectively in the turbo setup. You can get them cheap on ebay, but I got mine from autopartswarehouse.com, free shipping. If your current cat is in good shape though, you might end up with worse numbers with the magnaflow...it isn't as nice a catalyst at oem.
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