Hype

Well I'm back from Oz attempting to get my summer driver through AirCare (smog check) but...

Here's the history:

Car WAS an LG-4 with stock Qjet, performer intake, CompCams Pure Energy (smog legal with ~210 dur, or so), headers, NO CAT.

Passed aircare, although high-ish readings. A Cat is NOT required on pre-86 vehicles here, although it does have to pass the sniffer. Smog limits are pretty lax on pre-86 vehicles though, compared to newer cars.

I dropped in the 355ci with the specs below. I added the exhaust system below, (was edelbrock TES), system had a cat-cutout with a straight pipe in it at the time.
During aircare, car passed all checks (HC, CO, NOx), EXCEPT CO at idle was 3x the limit. Yeah, 3x. Everything else was passable.

So, I said screw it, garaged the straight pipe and added a high-flow cat in place. Changed plugs, rotor, cap, coil, (prolly needed it anyway), leads, oil, everything!

Still failed CO at idle by 1.5x legal limit, everything else had dropped considerably.

Then I decided to muck with the timing, kinda forgot about that. =). Brought it back down to only 4 degrees initial, threw back in the stock, stiff springs.

Readings even lower now, but still, CO fails at idle, but is now quite close. But the fact is, it shouldn't be anywhere near close with all this recent work.

I have a feeling its running rich at idle, during decelleration, like coasting down hills in 2nd for example, foot off the throttle, there is a very strong sulphur smell, like the cat is working overtime. But HC's at idle are actually quite decent now, so...?

The Qjet has not been dicked with besides bigger secondary rods and hangers. The jetting has remained the same from whatever came on a Canadian(NonCC) '83 LG-4, which I would assume to be calibrated quite lean from the factory, but who knows.

I have since popped off the cap that prevents you from mucking with the fuel mixture at the top of the carb, but then I stop and think that hey, I have no idea what I'm really doing here...

I have no idea if this carb has been rebuilt in its lifetime or not, and if not, it would have 150,000 miles on it. I would like to stay with the Qjet, it seems quite reliable and doesn't give up the gas mileage like my buddys holley 650 does. Yeah I know I'm giving up a few ponies, but...

I've checked for vac. leaks, it's all good there. I was told by an engine builder that the cam might be too aggressive to pass AirCare, but.. c'mon, an XE262?? We've gotten a '78 Malibu /w a 350ci with the old 222/222 ".440/.440" corvette cam (cat-less) through AirCare before, well it took 4 tries and hardly idled through the test after dicking with the Holley, but, it's been done.

Clues, anyone? I know there are some Qjet yoda's out there, and its gotta been in the carb.

Thanks guys!

Street Lethal

iTrader: (16)

Are you sure you didn't pop off the cap to the air-bleed valve (on top) instead?

The quadrajet has two mixture screws at it's base (that might be capped, or might not..... considering from what car it was pulled from, and what year).

You'll need a vacuum gauge bro. Turn the mixture screws (once you find them) until the gauge reads the highest it can. Of course you must do this while the car is in idle, in gear (do NOT have a buddy press on the brakes while you tune.... this obstructs vacuum, and you won't get a proper reading. Just put some bricks behind the wheels to hold her in place), and with the vacuum advance (on the distributor) unplugged....

If you're mixture screws are plugged, you can either find a small set of tweasers and adjust with them (by grabbing the tips of each mixture screw, then turning).

Or you can take them out, and make a slit in each of them with a hacksaw.... then put them back in with a regular screwdriver, and use the screwdriver to set proper mixture...