My car SMELLS like Gas???

[orlowted]

Hello all...I have a 65 stang with a new re-built 289 and it runs great. Problem here is - it Stinks...I mean inside the compartment. When I am driving - I get a fresh gas smell - Mostly when I hit the pedal hard. It has a Edelbrock manifold and same carb (650) - just bolted on. My mechanic told me to check the plugs and see what they look like...they are dry, light brown and what I would call clean. I did not do anything to the carb when I installed it...But it seems that I have 2 much gas going to the engine to be burned (explaines the smell??). Maybe this is normal, but I can't get my girlfriend in the car for drives because of the fumes. I can take it but she can't - and what fun is a Mustang alone???
Any thoughts on what I should look at....I am not a mechanic and do not want to mess up the way it runs great by turning dials on the carb housing.

P.S. Just rebuilt the toploader 4 speed myself...if anyone want a Top Notch Kit - Let me know and I can assist.....
TJ

[420nitro]

I am uncertain, but did your car come with a vapor canistor? If not, you may want to get one and install it. This will greatly reduce any vapors you may be coming in contact with. (your nose anyway)
Good luck

[KiltedBanshees93GT]

I dont know that its a carb problem, but something to check:
Is the exaust ok, i.e. not running too rich? My last Holley was way heavy on the fuel, and I had the same prob, along with bad exaust smoke. I couldnt seem to get the air-fuel balenced right, but I'm still figuring out. (believe me, I know the "screwing up the carb" phobia. The best learing tool is lots of research and careful notation of changes you make. If yours is still "out of the box" you have a baseline to go from. Just notate any changes you make,one at a time, and you can always make your way back to "stock" if need be.
Just my .02

J

[orlowted]

How do I know if I have one...vapor canistor? Motor was built from scratch and I know almost every part of the car, but this is a new one to me????
TJ

[420nitro]

Originally posted by orlowted
How do I know if I have one...vapor canistor? Motor was built from scratch and I know almost every part of the car, but this is a new one to me????
TJ

Vapor canister is something that catches the gas fumes from the carb and sends it back to the gas tank. Helps eliminate that raw gas smell coming from the carb and gas tank as well. Car will run well with or with out it, but when you go into the garage first thing in the morning, the first thing you smell is gas and it will seem like you spilled it onto the floor the night before.

So what you do is get a plastic one from any modern mustang and mount it on your car. One hose goes to the gas tank and the other goes to the carb. There will be two vents on top of the canister. Make sure that both are there or you will still have this smell. Now I am speaking of the vapor canister that came on my 92 mustang. I am sure they change over the years. Just go to your local bone yard and ask for one. Pick a year any year . My guess is as good as yours. Do some research or ask any of the other guys/girls if they know if your car came with one.
Good luck and hope this works for ya.

[Jeff65]

You need to isolate where the fumes are coming from. They could be exhaust fumes, gas tank fumes, fuel line fumes or fumes from the carburetor:

Gas tank fumes: old Mustangs have a fuel tank with a thin top in the trunk. If someone dropped a jack on the fuel tank, it can put a pin hole leak in the tank and consequently spread fumes into the passenger compartment. Clean the top of your fuel tank and then put duct tape over every square inch of surface area. If the gas smell goes away then replace your gas tank.

Carburetor fumes: if the float levels in the carburetor are set too high, fuel will sometimes slosh out of vents and onto the carb top areas. This leaves a nasty fuel smell that seeps out of the underhood area and gets sucked into the cowl vents. Use masking tape to seal the seam between the back of the hood and the cowl grille (cover the cowl grille). If the smell goes away with the tape on, then the fumes are coming from under the hood. Inspect the top of the carb and manifold for evidence of fuel leaks.

Gas lines: check every inch of the gas lines to make sure there's no pin hole leaks. Old lines get corroded and sometimes leak fuel. Duct tape any areas found and re-test for fumes. If the fumes go away after taping the lines, replace the lines.

Exhaust gases: A richly tuned carburetor can result in raw gas being expelled into the exhaust system. If there are leaks below the body and before the rear of the car, these can be smelled as if they were in the passenger compartment. Inspect exhaust system for leaks. Check exhaust pipes for evidence of rich adjustment of the carburetor (black sooty exhaust). If you find leaks, repair them. If you have black sooty exhaust, retune the carburetor to a leaner setting (should be grey looking exhaust).

Good luck!

[orlowted]

Thanks for all the great advise....The tank is new and the lines were gone over during the rebuild and much replaced. Carb is new as is fuel pump and all engine components...I do have some funny stuff going on with the exhaust system...long tube headers narrowed down to 2" H pipe using adapters and flanges...and then on to a cheap dual system. I noticed inside the headers there is Black soot type residue...not much - just like a thin coating. I am bandaging up the system this weekend before I puit the trans back in so that might correct the problem. I still have to believe that it is the carb, here is why...
I only notice the smell when I hit the secondarys on the carb (3/4 throttle or more) so I do believe it is not using all the gas being pumped into the carb or it is splashing over somehow. No signs of gas residue anywhere. I also looked for the Vapor Canister, but have had no luck yet.
Lets assume it is the carb....any thoughts. It is an 650 so I don't think it it too much for a 289?

[Jeff65]

Everything is new doesn't mean its correct. Example: when I fired up my new 5.0L (new engine, new everything), the carb float levels were too high causing some venting of gas onto the top of the carburetor. Resetting the float levels correctly fixed this problem.

First look for the obvious, evidence of fuel leaks. If there is no evidence then isolating the source of fumes is a good place to start. A little masking tape over the cowl grille helps. It lets you know if the odor you detect is coming from the engine compartment or from the interior (rear) of the car. The faster you narrow down the problem, the sooner you'll have it fixed.

[induction]

The '65 never had a vapor canister.Check to see or just replace the rubber hose that connects the fuel tank to the filler spout in the trunk. That is if your smelling fuel first thing when you get in the car. Do you have any holes in the floor pan or trunk that arnt pluged ? How ahout the lower shifter boot cover? leaks around the heater box? Is your heater hooked up or do you just have the tubes from the firewall open?

[orlowted]

I think I have found the cause...
I recently replaced the carpet and when I tore the old one out - there were small holes in the floor boards and I noticed there was not any sound deadner installed. I repaired all the small holes, added a complete sound deadner kit and replaced the new carpet. After a small drive last week...I noticed the interior noise was much lower and also that I did not get the smell. The real test will be when I get it on the highway, but for now - it seems that it was the poor insulation on the floor.
TJ