abagoz

I am new to the site, I hope someone can help me! Here is my issue, 65, installed a 5.0L fresh rebuilt engine, stock roller camshaft, cam in the straight up position, headers with complete exhaust to the rear bumper. Edlebrock intake and carb. This is a convert. With the top up the Hydrocarbons are killing me, car runs great and very happy with the performace. Jetted the carb down as lean as I can get it, moved timing around, pressure checked the exhaust system, sealed every hole I can find in the firewall and floor, backed out the idle air jets as far as I can. Everytime I take out for a drive I just reek of exhaust, like I was working a dyno running NASCAR engines.

HELP! I am open for suggestions, even thought of putting some catalyst's on this thing..

Waffles

Where in MI are you? I'm in Novi, maybe I can meet up and help check it out for you, but I'll tell you right now, your "exhaust problem" is in fact one of the best parts of these cars. I LOVE smelling like gas, oil, and exhaust. Everyone knows what car I drove that day as soon as I walk in the door.

tx65coupe

These old cars do not have any emissions equipment. That normal, unless it is extremely bad.

Carlos Pineiro

I assume you really mean exhaust and not unburned or raw gas.

You can smell unburned gas if you have no cat converter. Exauhst that goes through a cat smell cleaner.

Raw gas smell comes from leaks in the gas tank, usually from rusted tank tops which also serve as the trunk floor. the fumes will enter through the back seat.

If it's actually exhaust, check that the exhaust pipe tips extend beyond the rear valance. Many exhaust pipes are custom cut, bent, and installed as muffler shops don't carry 400 stock sizes. If the tip doesn't clear the rear valance sufficiently, moving air as you drive the car will direct the exhaust into your trunk and interior.

Try blowing smoke from a cheap cigar on every part of your exhaust from the ex manifold to the rear pipes, and look for leaks. If your exhaust is tight all the way, it shouldn't matter if you have gaping holes in the floorboards or firewall, you shouldn't smell fumes in the car. It's all about the pipes.

Also, any exhaust leaks in front of your mufflers will also be noisy.

Good luck. Tell us how it plays out.

CP

rmodel65

is your hood to cowl seal in place???

Stepman

"backed out the idle air jets as far as I can"


That will make it very rich! I have posted how to set those to where you won't smell the exhaust but, don't want to go thru it right now.

lunarweasel

That's what I was thinking.

wumarshall82

Sometimes I will smell like exhaust after driving my car but I can say that the cowl/hood seal did not help me. I didnt have one on my car until after I painted it but you can still smell the exhaust sometimes. I do need to seal the hole in the firewall where the a/c hoses come into a little bit better though so that might be my problem. Overall, I think the exhaust smell is something that you just have to live with when driving these cars

lunarweasel

I will ask my dad what they were like new. He had a 67 Firebird brand new. Maybe people just lived with it back then

abagoz

Typically when you back out he idle air circut (jets) you allow more air, therefore more air = less fuel. This has always been the case on Holley's (as I can remember) Has anyone every fixed it with modern catalyst's?