Can leaky injectors cause some smoking on startup?

[Welby]

I've been noticing some bluish smoke on cold starup, and was wondering if leaky injectors could have anything to do with it. The reason I suspect that they might be leaky is after shutting it off, the car won't hold fuel pressure for more than 30-40 minutes or so (I haven't timed it exactly). I could check the car in an hour, and the FP will be back at 0 lbs... They are stock injectors (I assume the original ones, but who knows). The car has 73,300 miles on it.
If I start the car warm it doesn't do it, and I don't notice smoking any other time.

Thanks Mark

 

[steveX]

A leaky injector will more likely cause a no start. Due to the excessive amount of fuel at start-up. Since you mension bluish smoke, this leads me to believe oil is burning inside the combustion chamber (no a good thing). this oil can only leak from two places. One is the VALVE SEALS, Two is the piston rings. If you only see this bluish smoke at start-up, it leads me to believe you may have valve seal issue. if the smoking still continue after warm-up, You should have a compression test/ cylinder leak-down check, or your valve guild are excessively worn out.

A smoky start-up only and will most likly be a valve seal issue. Since the spec on metal clearance changes when heat is apply, most likely what is happening here is the valve stem are expanding on warm up, and contract on cool-down, this is normal when with-in spec. most of the time, replacing the valve seal with quailty VITON seal is the way to go. I would also go the extra step and replace the valve spring (100,000+ miles),since you are going to be removing them to service the seals. good luck.

 

[grocerygetter]

my car had 119K on it when I bought it. It would puff a blueish smoke when starting. It was leaky fuel injectors washing down a cylinder wall or two...thus you get oil and a blueish smoke. Put in 30# injectors and no more smoke and cured my slow start problem. 73K miles=change injectors IMO.

 

[BuickMike]

Your fuel pressure leak could also be either an issue with the fuel pump not holding line pressure, or a leaky hose between the pump and the pickup tube inside the tank (if you have an aftermarket pump).

I'm thinking the blue smoke is most likely the valve seals / worn valve guides.