New engine...lots of smoke out the tailpipe

[93F250]

Just put the first real miles in on a new engine, 350 mild port 230/230 .050 cam, edelbrock 1406.
It did fine the short trips testing and what not but today it started smoking real bad if you let off the gas after giving it more than half throttle, let it idle too long, or dont touch the throttle down hill. At all other times it does not smoke.
At first i thought its burning coolant but it wreaks of gas, i tried re tuning the carb back to completely stock and i tried running it just off the fuel bowl, both with no change.
I checked it over this morning and it Does not appear to be losing coolant but my oil level did rise, it is NOT murky like it has water in it.
I noticed my valve cover breather was also puffing a little smoke at idle, same white/blue color but it is not oily at all. It smells like gas.

Car following me says white smoke, looked like it had a blue haze in the mirror. It seems to have started missing at the same time, could this be a lot of excess fuel not getting burnt?

Its 90 and i drove over 50 miles with no temp issues

Any help is appreciated

Sent from my SM-G935V using Tapatalk

 

[Kennyray]

Does your oil smell like gas? If so it's running real rich.

 

[93F250]

I found that the vaccuum modulator was leaking and cylinder 1 wasnt firing over 2k

Sent from my SM-G935V using Tapatalk

 

[Kennyray]

How's it running now?

 

[OldCracker29]

 

[93F250]

Well one fuel pump, a vaccuum modulator, pcv, oil change, and set of plugs later its running correctly. Still working on the tune, bogs when you mash on it (doesnt even really wanna run out my converter stall). Then its good when it picks up, plugs look great now

Sent from my SM-G935V using Tapatalk

 

[Kennyray]

Well one fuel pump, a vaccuum modulator, pcv, oil change, and set of plugs later its running correctly. Still working on the tune, bogs when you mash on it (doesnt even really wanna run out my converter stall). Then its good when it picks up, plugs look great now

Sent from my SM-G935V using Tapatalk

I think your accelerator pump need to be adjusted. Probably not giving it a big enough shot.

 

[93F250]

Well one fuel pump, a vaccuum modulator, pcv, oil change, and set of plugs later its running correctly. Still working on the tune, bogs when you mash on it (doesnt even really wanna run out my converter stall). Then its good when it picks up, plugs look great now

Sent from my SM-G935V using Tapatalk

I think your accelerator pump need to be adjusted. Probably not giving it a big enough shot.

Tried that. Not making much of a difference, its squirting perfectly though. I richened it up and it helped but its still bad when the secondaries open. Won't even spin the tires

Sent from my SM-G935V using Tapatalk

 

[Cowboy Cadillac]

Try tightening the secondary door spring if its a Quadrajet. Theres an allen screw on underside of spring tensioner on passenger side,back it off, turn in screw with screw driver 1/16 of a turn at a time, tighten, test drive. My mud truck ran like a bag of smashed ass because secondary air door opened too fast. Also check the vacuum "thing" on side still has bar attatched....too many idiots remove it thinking its stopping the secondarys from opening when they rev it up by hand underhood. the secondarys ONLY open up under load!

 

[Black02Silverado]

Glad you found the smoking issue.

It sounds like you need to keep tweaking the carb. All good suggestions above.

Just an FYI but smoking like you described is a classic valve guide seal leak if all else is fine. My 68 Impala with a 327 would smoke like crazy coming down the mountains in PA. When I would get to the bottom and have to give it gas from coasting down the 4 mile grade it would puff smoke and then clear up.