Can't get this thing running!

[NickFerrell]

I've been helping a friend with his 1980 (manufactured in October of 1979) fuel injected Spider.
It had sat for a while, so here's what we've done-
Dropped and flushed the tank
New Gas
Fuel filter
Plugs and wires
Ignition rotor

Still cannot get her consistently running! We discovered this evening that it will run very rough with the gas cap removed, and not run at all with the gas cap on. In fact, if we put on the gas cap while trying to crank it, the engine makes a "thud" and stops cranking.
With starting fluid, it starts up and runs beautifully for a few seconds.

We have the cold start injector unplugged, but doesn't seem to make any difference whether it's plugged in.
Last thing--when the engine gets running and is reved up, it fills a city block with white smoke, but it doesn't smell like antifreeze.
Help?

[So Cal Mark]

if it's been sitting for a long time, the injectors are probably stuck shut

[NickFerrell]

Pulled the injectors, cleaned and bench tested them. They're 100% now.
Reinstalled them, and it fired right up with no smoke. That is, until about 4-5 minutes of running, then the extreme white smoke started again. Any suggestions? Can't wait to have this one on the road!

[NickFerrell]

Also, the smoke doesn't smell like antifreeze. I know that sweet smell. Had it many-a-time on other vehicles. This smoke seems close to odorless as possible.

[azruss]

may want to check the relief valve on the fuel rail. may still have fuel contamination from the fuel lines.

[majicwrench]

white smoke = water, coolant, antifreeze, not much else. It's got a blown gasket among other issues.

[NickFerrell]

Figured it out! The main issue was the fuel pressure regulator. Was shooting gas through to the vacuum line. Replaced it, and she purrs like a kitten.
The smoke is still there, but I've identified it as oil burning. Smells like oil, blue tint. It's oil.

I'm sure everybody has dealt with this. Where to begin investigating?

[spider2081]

If the car sat for a while the rings might be stuck in the pistons. Some people like to use sea oil additive in fuel. Some pour automatic transmission fluid into cylinders and let it sit for a few days. There is a small chance one of those might work. When engine is at temp. Run it at high RPM for a bit then lug the engine in 5th gear a few times and see it that frees them up. I'm sure others will have more ideas on the issue.

[majicwrench]

My 72 almost always puffs after sitting. THis spring when I fired it up, it smoked quite a bit, even the first few miles on the road. Then it cleared up, and is back to puffing a bit on startup sometimes.
Glad you got er goin

[azruss]

could also be worn valve guides and seals.

[NickFerrell]

After 35 minutes of running, the smoke cleared up. False alarm?

[4uall]