My car is a 1982 Trans Am, originally an LG4, but swapped to a new crate 350. Whenever I do any hard driving, I always smell some raw smelling exhaust shortly afterwards. At about 3000 miles on the new engine, a misfire developed so I immediately yanked the plugs and they were totally black. Not only that, but they were undergapped at less than .035". I replaced the plugs with rapidfires at the proper .045" gap and checked the wires and cleaned up the distributor. Timing is dead-on at the stock setting. This seemed to make no difference in the car running rich.
The next thing I tried was changing the rods/hangar back to the set that came stock on the LG4. This also made no difference in the exhaust smell.
One thing I notice is that if I pull off the hose between the carb and the charcoal cannister, it always pours out gas, even if I just ran the car for a short time. Could this have something to do with the running rich problem?
Just for the record, I have replaced a ton of stuff, none of which ever made a difference - pcv valve, the vacuum cannister control valve, the thermal vacuum switch for the cannister, the cannister itself, the exhaust check valves.. I also verified that all of the solenoids in the AIR control valve function properly and there are no vacuum leaks in any of the valves. Aside from the engine being a 350, everything else on the car is stock, including a rebuilt computer controlled quadrajet.
Today, I took a spin with the cannister line disconnected and the hose plugged. It didn't seem to make the post-throttle exhaust smell anywhere near as much. I'm not sure where to take it from here.. The car runs strong otherwise, and passes NJ emissions with flying colors, however that exhaust smell and the plugs turning black so quickly are not something I want to leave alone.
One last note - this car is a 4-speed manual. On deceleration, I notice that blub-blub noise a lot more than I do on my auto transmission LG4 firebird and my crossfire. Is this related to my problem?
-Kevin
The next thing I tried was changing the rods/hangar back to the set that came stock on the LG4. This also made no difference in the exhaust smell.
One thing I notice is that if I pull off the hose between the carb and the charcoal cannister, it always pours out gas, even if I just ran the car for a short time. Could this have something to do with the running rich problem?
Just for the record, I have replaced a ton of stuff, none of which ever made a difference - pcv valve, the vacuum cannister control valve, the thermal vacuum switch for the cannister, the cannister itself, the exhaust check valves.. I also verified that all of the solenoids in the AIR control valve function properly and there are no vacuum leaks in any of the valves. Aside from the engine being a 350, everything else on the car is stock, including a rebuilt computer controlled quadrajet.
Today, I took a spin with the cannister line disconnected and the hose plugged. It didn't seem to make the post-throttle exhaust smell anywhere near as much. I'm not sure where to take it from here.. The car runs strong otherwise, and passes NJ emissions with flying colors, however that exhaust smell and the plugs turning black so quickly are not something I want to leave alone.
One last note - this car is a 4-speed manual. On deceleration, I notice that blub-blub noise a lot more than I do on my auto transmission LG4 firebird and my crossfire. Is this related to my problem?
-Kevin
Supreme Member
Theres definatly something wrong with your evap system. There should never be liquid gas there, only vapors.
Check the lines running to the tank and the carb for fuel.
Check the lines running to the tank and the carb for fuel.
Well.. The vapor line that goes to the fuel tank seems to be okay, I can send compressed air thru there and can see fumes coming out of the tank with the cap off. The cap is brand new as well, and it's a direct part number replacement of the original cap from gmpartsdirect.com. It seems far-out that the gas would source from the tank and get sucked all the way back into the car. It seems more likely that it is somehow coming out of the carb.. But I rerouted the hoses a long time ago and the one coming out of the carb bowl loops up as high as possible before it goes back down, though this seems to have done nothing to for the problem. Another thing possibly related - the air filter on this car gets rather gassy/oily a lot quicker than on my other two firebirds.
Update -
I believe this fuel was coming from the carb.. I noticed a small amount of gas around the shaft for the accelerator pump. Seeing that, I yanked the top of the carb off and messed around with the float, though I didn't really change anything drastically. I was hoping to find some crud in there stopping the needle from sitting properly, but it was very clean. So far after a day of driving it looks like the vapor line is dry. I'll see after some more driving if that really solved it.
I believe this fuel was coming from the carb.. I noticed a small amount of gas around the shaft for the accelerator pump. Seeing that, I yanked the top of the carb off and messed around with the float, though I didn't really change anything drastically. I was hoping to find some crud in there stopping the needle from sitting properly, but it was very clean. So far after a day of driving it looks like the vapor line is dry. I'll see after some more driving if that really solved it.