FUMES FUMES FUMES

[bs383cuda]

So i am still relatively new to mopars but i am lost and can't get a handle on this. so when my car is at idle it has fumes that can peel paint. i know that it is a combination of jets idle fuel mixture and timing but for some reason i cannot get it set right. first off i have a 1970 Cuda with a 383 4 speed. it has full msd ignition, a purple cam, stock bottom end, ported and polished cast heads, standard comp cams push rods and lifters, edelbrock worker intake, holley double pumper, and dual exhaust going out the rear valance. the drivetrain has around 4500 miles on it total. has anyone had this setup and knew what to set everything to? i could use the mopar families help! thanks

[70chall440]

Are you taking about with the car in a garage or out in the open? Exhaust fumes can give you an indication of the car running too rich (smells like raw gas or close to it), however if your set up is close or at where it needs to be, you are still going to get some very noxious smell regardless (I went through this same issue thinking my car was too rich or had some issue, then put a O2 sensor on it and realized it was actually on the lean side). We tend to forget that old cars give off some rather nasty exhaust as we have been dealing with modern cars with catalytic converters etc on them which reduces most of this.

I am not saying your car is set up right, however I would not necessarily think it wasn't based off the exhaust fumes. Check it out methodically; start with the fuel side; is the carb set up correctly, are the plugs burning right (light grey/white), then go to ignition; set your initial and total timing. The main cause of the fumes is typically timing (not burning everything), however what you may be smelling might just be a hot mopar...

[HP_Cuda]

AFR will tell you everything you need to know.

 

[Markp]

Are you taking about with the car in a garage or out in the open? Exhaust fumes can give you an indication of the car running too rich (smells like raw gas or close to it), however if your set up is close or at where it needs to be, you are still going to get some very noxious smell regardless (I went through this same issue thinking my car was too rich or had some issue, then put a O2 sensor on it and realized it was actually on the lean side). We tend to forget that old cars give off some rather nasty exhaust as we have been dealing with modern cars with catalytic converters etc on them which reduces most of this.

I am not saying your car is set up right, however I would not necessarily think it wasn't based off the exhaust fumes. Check it out methodically; start with the fuel side; is the carb set up correctly, are the plugs burning right (light grey/white), then go to ignition; set your initial and total timing. The main cause of the fumes is typically timing (not burning everything), however what you may be smelling might just be a hot mopar...

I personally love the smell of a 70s Challenger or Cuda no cats exhaust smell. It's the smell of muscle.

[cudabob496]

what do plugs look like?

exhaust leak?

try increasing idle speed

[bs383cuda]

the car runs great and yes the fumes are out in the open. it was bad enough to cause 2 people in the car behind me have to cover their faces with their shirts when sitting in traffic. yes their windows were up too. although they were driving a honda so who knows. haha. i do too love the smell of carb'd engines but this seems to be a little excessive but shoot maybe its a hot mopar. this is my first so it is all new to me and i am used to working on my 81 cj8 with amc 360. spark plugs look a little rich but not horrible and there is no exhaust leak.

[70chall440]

If that is the case, I would say your timing is off somewhat. In my own efforts of setting up my EFI system, I have noticed that the exhaust fumes definitely intensify in smell with variations in timing. In essence, the spark is occurring a little late in the cycle and not completely burning everything before the exhaust valve opens which pushes all those unburned hydrocarbons out the exhaust pipe which is what your Honda friends were smelling. It doesn't take much to make this happen, a few degrees off will produce this effect. Now, having said that; your initial timing might need to be where it is in order to achieve the overall (total) timing you want for performance when you hit the go pedal. In short, this is a compromise and you need to figure out what you want and can live with.

[Fern]

You can always mask the smell

https://www.summitracing.com/search/brand/power-plus-lubricants/product-line/power-plus-fuel-fragrances?SortBy=BestKeywordMatch&SortOrder=Ascending

[cudabob496]

last time my car did that, carb was way out of adjustment

[EMCD]

So, mine does the same thing. I checked AFR and its within spec. I believe I'm too used to new cars and the lack of smell. Everyone that owns classic cars says I'm crazy and that the stink is normal. I swear at a stop light I lose 2000 brain cells huffing those fumes.

[cudabob496]

once car is warmed up, its not as bad.
But the carb idle circuits need to be set up correctly

[70chall440]

So, mine does the same thing. I checked AFR and its within spec. I believe I'm too used to new cars and the lack of smell. Everyone that owns classic cars says I'm crazy and that the stink is normal. I swear at a stop light I lose 2000 brain cells huffing those fumes.

 

[RCCDrew]

Is it true that the fumes are greatly reduced with FI?

[Katfish]

the car runs great and yes the fumes are out in the open. it was bad enough to cause 2 people in the car behind me have to cover their faces with their shirts when sitting in traffic. yes their windows were up too. although they were driving a honda so who knows. haha. i do too love the smell of carb'd engines but this seems to be a little excessive but shoot maybe its a hot mopar. this is my first so it is all new to me and i am used to working on my 81 cj8 with amc 360. spark plugs look a little rich but not horrible and there is no exhaust leak.

Same situation for me, unfortunately I think it's normal.  I've tuned mine with minimal improvement.  The crappy ethanol gas and the open venting system design these car have is a bad combo for fumes.
I always have to leave my garage open for an hour after coming home to clear the air.

I have used that gas perfume in the link provided and it works, but it gets a little expensive.

[73440]

l. I swear at a stop light I lose 2000 brain cells huffing those fumes.

Iuse the same 110 leaded in the Harley as in the Barracuda and I take the gas cap off the bike at the light and smell it. Im probably past worrying about brain damage , well anymore brain damage that is.
Love that smell!!