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Exhaust/gas stink!

Hi all,

My 67 Camaro has had a horrible exhaust stink for awhile now. It's bad enough that just starting it up and pulling it out of the garage is enough to make you sick to your stomach, make your eyes water, and stink up your clothes until they're washed again. It's so strong that my wife complains about the exhaust smell when I walk in the door, you get the picture. Odd thing is it runs GREAT! Plenty of acceleration, no bogging, not a complaint in the world performance-wise, it just smells bad, REALLY bad.

Last year I rebuilt the motor thinking the rings were shot (which they were), but that didn't change anything as far as the stink goes. I recently replaced the stock points ignition w/ a Unilite, Powermaster coil, and HyFire box. Still no change. Just replaced the fuel pump this weekend, again no change, maybe worse? It's a more or less a stock motor with headers and a 272H Crane cam. I don't have much knowledge about the old Q-Jets, and I'm sure with the right know-how it would be an easy fix.

If anyone can lend some advice on tuning a Quadrajet (4MV) for less stink, or what to look for, it would be greatly appreciated! I've considered one of Edelbrock's Q-Jet units, but I'd rather save my money since I'm sure it's a simple fix, considering it runs so good right now with the old carb. I've considered a carb swap too (square-bore), but don't want to make that change if there's not a good reason to do so.

Thanks, Scott

PS: I've already checked the operation of the choke and it's fine. It's the style that runs off the heat from the intake. Starts choked when it's cold, then opens up after running for a couple minutes.

Reply to
Doomie
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It can't be running "good" if your eyes water and it stinks like that. That thing has to be a gross polluter.

Have a shop put it on a gas analyzer and help tune it for best emissions and power as a combination. That should help things a bit. Also, make sure all the tuneup components and mechanical health of the engine are in order. Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director '80 Carousel Red Turbo T/A, 27k orig. '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 143k and still going.... '91 S10 Blazer 4.3Z

Reply to
Bigjfig

One thing to consider is if the area you're in has recently changed to oxygenated fuels (the EPA mandated stuff for regions declared non-attainment areas) or if alcohol is being added to the formula. I've seen the change in two different areas of the country and both times I've heard many people make comments about the exhaust smell. Your description parallels those comments with the exception of your mentioning watery eyes. To me the odor started to remind me of rotten eggs but not as strong.

My opinion is that if the carb is set wrong and that is causing your watery eyes then it is too rich. I fix boat engines for a living and do work with a lot of GM engines. The water eye thing is one of my tests for checking my tune-ups. If I can stand close to the exhaust for a minute and my eyes don't swell shut (or I don't fall over and start to wheeze) I figure I've done ok and the fish will probably survive.

Reply to
Ken

First of all if you do not know how to tune a carburetor, you need to take your car to someone who does it for a living.

Have them use an analyzer on the exhaust as Joe mentioned, as well as check the vacuum signals.

Probably your problem is a combination of things. Wrong heat range plugs, air-fuel ratio too far off, cam timing may even be a bit out.

Seat of the pants tuning can only get you so far. Charles

Reply to
Charles Bendig

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