Ive got an '89 Formula 305 tpi with 50k miles. When I start it when it has sat for about 30 minutes after running, it puffs a little smoke about 5 seconds after it starts. Can't really tell what color but it doesn't look blue and dissapears rather quickly. I don't notice any smoke when it is cold. You guys think this is a leaky injector or valve seals? And one of the injectors looks different than the others, maybe it was replaced?

 

a leaky injector would look rather black.

If it's more white, depending on where you live it could just be condensation in the intake overnight.

Of course if it has a bluish tint, (and smells like oil burning) it's your valve seals.

 

My 305 did that same thing from 80xxx to 107xxx and never seemed to loose a bit of oil on the dipstick. Everyone I know with a 305 has the same little puff on startup. I wouldnt worry about it unless oil is showing up on the plugs.

 

My old 4.3 did the same since the beginning of time. Oil never showed on the plugs tho so I never messed with it...

...well, you know, until I took the whole engine out

 

Maui,

That's the "Chevy Salute". It happens quite commonly on SBC engines. My '86 started doing that at less than 18,000 miles. The oil level never diminishes and there is so little oilbeing burned that it will not foul the plugs, oxygen sensor, or cat converter. Unless the smoke is a real annoyance to you,you really don't have to do anything to repair it. Just maintain the vehicle normally and enjoy the extra valve and upper cylinder lubrication on startup.

If you think that is a problem, cruise down to your local air field and watch the ground crews walking the props around on some of the old DC-3s and -6s and other radials before startup. This is done to expel the accumulated oil from the lower cylinders before starting to avoid hydraulically locking the cylinders. When they first fire up, hold you breath if you don't like the oil smoke, because it's gonna spew...

I know you have some air fields in Wichita, and even though the manufacturers there have forgotten about radials, they still fly.

 

Is it common for it to puff some smoke when it is warm and not sat that long?

 

I dont remember if mine did that when warm or not.
You can do a resitance check on the fuel injectors with an ohm meter. Its not the most accurate way to check them but it will point out really obvious problems with them.
unplug each injector and put a meter on the 2 prongs. All of the injectors should be close to eachother . I had a set go bad and they were like 16ohm and the next one would be like 2ohm and then 35ohm. They were all over the place. I dont remember what the spec was on the value but you could post on the boards about it someone will know. Or do a search for it I know its been discussed on here before
They are on 2 circuits left bank and right bank. Its been my experience that if one is bad it takes the others out with it.

I would keep and eye on the plugs and oil level that should rule out the possibility of oil leakage and help you narrow it down.
Sounds to me like the typical Chevy Salute