Gsa fumes from exhaust/running rich

[67 GTA]

I need help diagnosing my problem. My 67 is running rough, and really rich. It smokes most of the time. Usually white to grey in color. If I hold my hand to the exhaust tips they smell like gas. Spark plugs will foul out and turn black and smell like gas. Ignition is fine. Looked for vaccum leaks, changed intake gaskets also. Engine is basically stock, except for Edelbrock 600 cfm. Runs fine under acceleration, only runs rough at idle. When I tried to adjust the mixture screws they had no affect. They actually bottomed out without killing the engine. This is why I tried looking for vaccum leaks, but could not find any. What else could cause this? It ran this way when I bought it, but got worse after the intake and carb swap. I have good compression, but do not know what condition the rest of the internals are in. Could it be valve seals?

 

[10secgoal]

Nah, stop worrying. It's not the seats. I would geuss your fuel pressure is just too high. Especially if you had the problem before. My guess is you had a holley before. Edelbrocks are more psi sensitive. The fuel is probably just being pushed past the seats and making it way into the motor without being invited.

 

[67 GTA]

When I bought it, it had a Holley 600 on it. I put the Edelbrock and a Stealth Wieand intake on. How can I check the fuel pressure? What is it supposed to be?

 

[10secgoal]

When I bought it, it had a Holley 600 on it.

If you have rubber hose, just buy a fuel pressure guage. It is a guage that ranges from 0-15 psi and has two male ends to slip between two hose ends. Just cut your rubber hos somewhere and slip it in. Edelbrocks should 5-5.5 psi.

 

[67 GTA]

Well, I bought a fuel gauge and regulator. I put the gauge on first to see what the pressure actually was. It stayed around 5 psi. I put the regulator on since I already had the hose cut. The engine looked pretty clean, and I keep fuel cleaner in every tank of gas. If the valves had carbon buildup they should be clean at this point. I guess I'm leaning toward worn out heads again. That sucks. I figure someone went through the engine before I bought it and did not touch the heads because the compression is perfect. The valve springs and rockers look original. I guess I will wait until it quits and just go through the whole engine.

 

[10secgoal]

Would still look into the carb. If it's not responding to the air idle mixture scres, there is fuel getting in somewhere.

 

[MitchGT]

White smoke is usually oil or coolant. Since compression is still good, the rings are good, so it is less likely to be oil. Since you just changed the intake manifold gaskets and it got worse, I would say it is a coolant leak from the manifold. Check to see if your coolant level is low. If it is, then you know what to do! Both coolant and too much gas can give the exhaust a sweet smell, but gas makes black smoke.

 

[67 GTA]

I have checked for coolant loss, water in the oil, and bubbles in the radiator and did not find anything. That was my first thought before I started on the fuel system. It has a new radiator, but I can smell antifreeze burning sometimes when I have run it awhile, but do not seem to be losing any. It runs between 150 and 180 degrees.

 

[GrandeStang73]

Have you tried to change out your carb jets? I didnt have the same problem, but i ran rich, so i put smaller primary jets in and .1 lager secondaries. It fixed my problem.

 

[10secgoal]

Have you tried to change out your carb jets? I didnt have the same problem, but i ran rich, so i put smaller primary jets in and .1 lager secondaries. It fixed my problem.

Jets will only effect the AFR's when the main cicuit is running, not at idle.

 

[69Rcode_Mach1]

Could also be a powervalve, if you have had any backfires that would blow it. I don't think the edelbrocks come with blowout protections circuits for that do they? Might want to look into that too.