I had until Wednesday to AirCare my truck, so I go in today. Note that I have a 300 engine with a dirty carburetor that's heat soaked from the header, a punctured vacuum advance diaphragm, a bad exhaust leak at the collector causing a lean condition, and a 1/4-1/2 throttle hesitation.

I was genuinely surprised at my results, and keep in mind that here in BC they aren't very lax to older vehicles.

Driving test:

Hydrocarbons (HC) -
Average: 85ppm.
My truck: 72ppm. I was below average!

Carbon Monoxide (CO) -
Average: 0.63%
My truck: 0.13%. Again, well below average. This is odd.

Oxides of Nitrogen (NOx) - I was above average but well below the 3702ppm maximum at 1352ppm.

Idle test:

CO -
Average: 1.6%.
My truck: 0.22%

HC (This is where I failed) -
Maximum: 920ppm.
My truck: 1284ppm.

It's interesting how my truck was 3 out of 4 times below the average and for tonnes of CO2 per year was past the target, but was over the CO at idle.

Is there any quick fix trick I can do? I can still insure it for another three months so I have time, but I don't want to be throwing parts at it. If I have to spend money on the truck I'll just stick to my plan of getting my '73 registered in Canada and drive that until January when the AirCare program will be gone, in which time I'll pull my engine and build it up.

 

You have the same problem I did tro, for me it turned into a nightmare. But I think your solution will be in a tune up, fixing your leaks, and rebuilding the carb to eliminate your lean condition.

 

Bah. I've got a carburetor for it with an intake manifold on back order and I'm saving for a DUI distributor and a new exhaust system. Last thing I want to do is rebuild things I'm replacing. I actually just did a tune-up though, excluding the distributor. I managed to get more power and had to lean it out, giving me 3.5 more city MPG. I'm happy with how it drives!

 

Yea I know what you mean. I've dumped a sheet ton of money into my engine trying to make it run right. Parts add up fast.

I'm actually chasing the same problem right now with my edelbrock. Playing with different jets and metering rods trying to find that sweet spot.

 

Is there not an "age limit" for vehicles that need the sniff test??????

Two options……

1. buy a bottle of that never fail stuff you put in your gas before the test. I think you can get it at any auto parts store. I know two people that used it and it worked.

2. Move to Texas where there is no sniff test required on vehicle 30 years old or older. Or registered as a classic or antique.

 

High HC can be caused by a lean condition. I'd fix the exhaust leak and replace the vacuum advance, and check all the vacuum hoses and intake seals/gaskets for any other vacuum leaks. Rather than rebuild the carb I'd first take a shot at cleaning it and maybe run a can of Seafoam through the engine. You said you did a tuneup, so the plugs and wires are new? How's the rest of the ignition system? I assume this is the '69 in your sig, so does it still have the points system? how are the points, did you clean or replace and reset them when you did the tuneup? You said it was excluding the distributor so I'm not sure if that means you didn't touch the distributor at all...how's the timing? is it set within a degree or two? Decent compression on all cylinders, no dead ones? All this can affect HC, but short of a worn out engine you should be able to take care of most of the above without spending a bunch of money, mostly just time. Depending I guess on just what the cause of your bad exhaust leak is...

 

I failed Aircare twice here in Vancouver recently. Two tricks I was advised to try:
1. Add 1 litre of isopropyl alcohol to approx 1/4 tank of gas, which in Vancouver is probably already 10% alcohol;
2. If you engine is well worn, disconnect the pcv, plug the carb fitting and let the pcv vent to the atmosphere.
I hate Aircare too. I'm thinking of retiring the truck until 2015 if I fail again.
Eric

 

Have you adjusted the air fuel mixture screws using a vacuum gauge?

 

I'll bet money your problem is the lean condition. Rebuilding the carb may or may not take care of it. Something is wrong with the cruise circuit. I rebuilt and cleaned my 2100 3x over and I could never get it fixed.

 

The only reason I have to AirCare the thing is because I imported it. It could be a 1920 Deusenberg and they'd still want me to run it through AirCare. I get a year freebie at most and then after that I need ye ol' sniffer up the rear.

New plugs, wires, air and oil filters, checked the rotor and dwell and that kind of thing, checked timing, checked compression (pretty even 150-165 across the board). The only reason I've never replaced my vacuum advance module is because the P/O replaced the distributor - a new one - with what I believe to be from a dentside but I can't read the part number on it and quite frankly the truck ran well enough for me to not care as I knew I'd be replacing the whole thing soon enough.

The exhaust leak is only causing an inconsistent lean condition on acceleration. At idle it's not enough to do anything. The truck actually smells rich the longer you let it idle, and from looking at my report I could see that my HC became progressively worse through the 30 second test. I have an Autolite 1100 with a single adjustment screw. I couldn't lean out the truck any more or it wouldn't idle high enough.

I thought about using that never fail stuff but I wasn't sure how well it would work.

AirCare is being ended in December so I'm quite alright with driving it for another three months and parking it.

 

Yep, exact same problem I had. I never got it fixed. That 2100 I have is just screwed...

Could you just do an exhaust gasket? Use some copper rtv to help seal it up if needed.

 

The answer to this is yes, but there's a reason I haven't done it already. To pull my exhaust, I have to lift my transmission, pull out the cross member, lower the transmission and rest it on something, wiggle the exhaust out, install the gasket, spend all day trying to get my exhaust back in (not easy), raise the transmission, insert the cross member, then lower the transmission. It's a pain. A month ago when I was dead set on actually having my new exhaust system installed, basically on the day I was going to have it done, my hood flew up as you know so out went my exhaust money, and pretty much all my money because I bought a BMW on that day as well. It's just something I never got around to doing because I'd always been expecting to replace the whole system.

But, seeing as how I won't be installing duals any time soon, I'll probably just get it over with and throw in a new collector gasket.

 

Oh geez, yeah I wouldn't want to do all that either.

 

Part of the problem with making the adjustment yourself Jackson is that your HC and CO numbers do not necessarily correlate to a perfectly running engine. My '66 352 passed HC but failed CO, just the opposite of yours. I also passed the driving test. I adjusted everything using a vacuum gauge and tachometer and it seemed to me to be idling perfectly. I have been told by an expert that the idle settings are a delicate balance - a small adjustment might cure the HC problem but create a CO problem, and vice versa. One solution, although slightly expensive, is have a shop with a smog machine adjust it to "pass" readings and fly down to Aircare.
Eric

 

I used a vacuum gauge to tune mine. It's got 22" at idle.

I guess I'll just get my '73 going. I don't want to spend money on the truck just to pass emissions.