battsup

Before i had trouble with my CO's at idle, well i set up the car and ran it through, well it passed the idle with flying colours but now it failed on the CO's of the driving test!!(2.75%, max was 1.19 :cuss )
What should i do.

turtlevette

i didn't know Canada had emissions tests.

Assuming you have a QJ maybe you could pop the cover off the altitude bellows and crank in on it a few turns and retest.

Correction:

if high HC is rich and high CO is lean maybe you need to open it a turn or 2 to richen it up.

Edit:
i see you have a carter carb. You might be screwed. I don't hink they are very tunable.


[Modified by turtlevette, 9:26 PM 4/3/2004]


[Modified by turtlevette, 9:28 PM 4/3/2004]

MotorHead

Jeese BC has worse emmission laws than Ontario ? They only test to 20 years old here so you would not need a test here. When I lived in BC any peice of crap with 3 wheels was driving on the road, no safety tests no nothing :confused:

Sorry to hear you failed what they do around here is take it out on the highway for about 20 minutes prior to the test it seems to help :D

neverendingproject

pick up an edelbrock calibration kit for their 600cfm carb. set yours up one stage richer. they have the instructions on their web site. who knows, you may pick up a few extra ponies as well.

battsup

arent the CO's caused by running too rich?

zwede

You need to lean the primaries a few sizes. I think the carters have the metering rods as well as jets, right? You can probably just get different rods that will lean cruise/low load without changing full throttle.

It may be tricky to pass without a catalytic converter but if they allow over 1% CO at speed it should be doable.

lyndave75

They're talking about not renewing the Aircare contract in 2006, so you have enough time for a frame off resto!!! :smash:

battsup

:thumbs:
ya i heard about that too, but i will be shipped off to university in victoria in september.

Zwede- no they dont allow you to be above at all. Its weird because like i've said before the car passed with flying colours 10 years ago, the only thing that has changed since then is that i rebuilt the carb and replaced the sparkplugs with some bosch platinum's.

73 LS-4

I don't know how many retests you get up there but try it with a set of normal A/C plugs. I've had many a car pass on standard plugs that would fail on bosch platinums. I'm not saying this is a problem in your case but it is something to try.

:cheers:
Pat Kunz

Willis

I would say to ditch those expensive piece of crap spark plugs and switch to some regular AC Delcos. Those plugs just don't seem to do to well in our older engines. They are fine for those cars that recommend them, but everytime I've had a poor running engine with platinum plugs, the remedy was to get the AC Delcos or Champions installed and the car/truck would run like a champ.

71coupe

You may need to re-install the cats - The good thing is that the coverters they make today are way better than the original.

LemansBlue68

High CO is almost always due to running rich. You may also be running near the limit for HC's. You need to decrease your main jet size to lean it out a bit. Also make sure that your air filter is clean and choke is functioning correctly. If you have an air injector pump, make sure it is operating correctly.

Retarding spark slightly may also help. This increases exhaust temps slightly and tends to promote further oxidation of CO (to CO2) in the exhaust manifold. The biggest effect, however, is due to too rich A/F.

Good Luck!! :thumbs:

battsup

I phoned up my local parts shop and the guy on the phone reccomended that i just go and buy some methyl hydrate and that this will lean out my carb enough to get me through. any oppinions on this?

Jvette73

:iagree: Retard the ignition timing for the test. It wont run as good but should blow cleaner #'s. Then after you pass just reset it to revive the poerformance. I had an old Pontiac that just wouldnt pass no matter what I did. I cut the timing back from the factory setting of 8 to about 2. It ran kinda sluggish but blew significantly better #'s in all catagories and got the fast pass.

battsup

I should have made this chart earlier but i think it will make analyzing the problem easier.


94 was the last time the car passed through aircare and then it sat for 9 years

Aug. car was put back on the road

Mar went through emmisions after rebuilding carb and sealin hole in secondary circuit

April had a mechanic at work spend some time trying to tune the carb before testing.

My theory is that the high HC were caused by the hole in the secondary circuit and that raw gas was being dumped into the manifold but i cant see why the car would pass on the CO's in 94 and not now.


[Modified by battsup, 8:39 PM 4/5/2004]

71coupe

The NOx reading is low. I would start there and work backwards. Was the car fully warmed up before testing? You really need to get the motor hot & keep it running before the test.

battsup

o i just found one more sheet, this one was taken 30 minutes after the march aircare. I had let the car sit with the hood oped and then took it back through

Driving________________________Idle
HC___CO_____NOX____________HC_____CO____ _
63____.72_____1374__________222_____4.29

MN-Brent

I had a problem once with an old 78 camaro. I took it to a small shop where the tech put the sniffer sensor in the exhaust pipe and showed me the readings. He then pulled the vacuum advance to the distributor and the both needle readings dropped like the guages were turned off.

He said, "you want to drive the car or do you want to fix it?" Since the car was rusty but trusty, I pulled the advance and passed with flying colors at the testing station.

This did have the cat installed though.

Brent...

Jvette73

Pulling the advance hose has the same basic effect as retarding the timing. Matter a fact it does retard the average timing over the scale of operation. retarding the timing is the only thing that would get my old beater thru emmisions. :yesnod:

NHvette

A heavy dose of drygas (Isopropyl Alcohol) can help burn cleaner #s.
I have also seen a technician disconnect my Mustang vacuum advance to get
her to pass.
If you do all the things in the thread, your car will be cleaning the air as you drive it.
:seeya