I have a 91 z28 5 speed with a 350. still have the 305 ecu and knock sensor. the injectors are factory 350 injectors. when i sart my car it puffs smoke. Its blue so i know i need to replace the valve steim seals. but its also white ish and smeels like raw fuel. and if i set still and let the car idle it smokes more white ish smoke. and the longer i set the worse it gets. but if i take off down the road it eventually quits smokin. does anyone have a clue what this could be? everyone i talk to says gas smoke is black that it must be burnin oil. but the only time the smoke is blue and smells like oil is when i first start it. after that its all white ish colord and smells like gas. i'm stumped so if anyone has any good ideas let me know. its getting kinda embarassing setting at red lights smoking out the people around me.

 

sounds like your running realy rich. this is prob from a stuck injector. sounds like u need new injectors go to a junk yard and pull used ones unless you want to spend $250 to $350 for new ones.

 

I actually posted something similar to this but was thinking it only happened when my car was sitting over night and then occasionally it would be hard to start. Since that post, my car has been starting perfectly every morning and running great. I am going to measure the ohms on the fuel injectors but the smoke I am getting regardless whether the car starts great or has a hard start morning...which will actually go away if I touch the gas pedal while starting...then pull key..then restart....then runs perfect.

My car only has a little over 50K original miles on it. I am thinking that the old SBC used the umbrella style valve seals and that they have just cracked and as result oil gets past them and this is the smoke that I see when I first start the car. Fuel does look dark grey/black when it is rich. White is supposed to be water...but oil can be a light grey w/bluish tint. I run back and smell the cloud and it doesn't smell like fuel..unless of course the substrate in the Catalytic Converter is changing the smell....substrate in Catalytic Converters has changed significantly in the last 10-20 years.

 

thanks gary ill try that and ill post the outcome.

 

an injector problem is possible.
but first thing i would check is the fuel pressure regulator. pull the vacuum line on the fuel pressure regulator and check for any signs of fuel in the line or the fitting. if you find any liquid fuel there, the regulator is bad and will need to be replaced.

if you do need a set of injectors, i would not get them from a wrecking yard. at best you'll only be getting the same thing as you have now and more than likely they will be worse than what you already have.
you can get a full set of rebuilt bosch 3 injectors which are drop in replacements for the 22# multecs from FIC for around $170.00.
you can get a set for even less at his E-bay store.
http://fuelinjectorconnection.com/sh...&productId=134

 

I have the same problem only mine is a tbi

 

same exact problem but my car is carbureted also idles roughly.

 

What you have the same problem too then