Puffs smoke and extended crank time (cranks fast and strong) and finally 'catches' and blows a little smoke - only when warm or hot. If shutdown when warm/hot and started within 5 minutes or so, starts without problem.

If car sits for a few hours (like over 4, it's fine)or overnight, starts quickly.
Car idles perfectly, doesn't overheat, and has good power.

I've had a similar problem a few years ago when hot - the ignition coil was bad. Car would crank forever but wouldn't start until it cooled down. Coil has been replaced (stupid accel) with stock new gm coil 2 years ago.

Fuel pressure: 44psi at shutdown. Goes down to 12psi or so after 25minutes. Am I looking at a faulty fuel pressure regulator or leaky injectors perhaps?

 

well if the starter was getting heat from the passing exhaust, then it wouldn't want to fire while hot.. They make heat shield to absorb the heat, do you have one of those on your starter?

Timing being off would also cause that problem, put on a timing light n check where your at.

the smoke is a effect on MOST if not all chevy engines, what color is it? Black? white?

 

The starter cranks nice and quick so I don't think that's the problem. The timing may be another issue. It was adjusted 'by hand' by a good mechanic since I don't have a timing mark on the car. The owner before me who did the timing cover (replaced with Mr. Gasket chrome one) did not put on the timing tab...basically, my timing is done by 'ear'. Never any pinging though, smooth idle and passes emissions tests so I'm guessing it's prety close...

Timing may be something though. Good point. Does the distributor (from the top) turn clockwise to advance or is it the other way around...can't remember. Let me know. I'm gonna make some reference points and give it a shot.

Thanks,
Steve

 

You might also consider a fuel mixture (flooded) issue on hot restarts. If you shut off the engine hot, wait only 10-15 seconds, then restart, does it start normally? What about after waiting 15 minutes? If it doesn't start well after some heat soak, you may have excess fuel from a leaking injector or FPR.

For reference, the distributor turns clockwise as viewed from the top, so advancing the timing would require turning it anti-clockwise.

 

All-mighty Vader. Thanks for the insight.
Let's say I'm stopping at the pumps to put some gas in...no problems, will start without incident. If there's a long lineup, then it'll probably delay just a touch and then start up - this is the sympton that leads me away from the heak soak problem. When the engine is turned off and still hot under there, the excessive crank time should be immediately realized upon restart since everything is good and hot.

If the car sits for say 10 mintues and is warm, it will definitely not start until she's cranked for at least 4 seconds (followed by a puff of smoke).

When completely cold, the car starts very quickly (sitting for hours or overnight).

My fuel pressure bleeds off quite slow - then again - I don't have anything to reference the change against. I know that after 25 minutes or so, the pressure had fallen from 45psi to 12 psi.

 

That's actually a fast bleed-off time. I drop 10 psi after an hour of the car sitting.
I agree with Vader. The regulator or the injectors are suspect. I'd lean towards the injectors myself.

 

Thanks a lot man! I wonder if anyone else can atest to that reading too. It's a pretty slow bleed in that you can't really see the guage move but you I look back a few minutes later and the change is evident. As I said, I'm dropping from 44psi or so right down to 12+/- 5psi after 25 mintues.

Can anyone else provide their readings and if they're similar to Viprklr?

Thanks everyone!

I'm planning on changing the fuel pressure regulator this winter along with the EGR valve so now may be the time to install new injectors. On the other hand, I am planning on going with a 350tpi of some sort a few years down the road (as opposed to my 305tpi) so I wanted to hold off on the injector purchase.

Is there a sure fire way of testing the pressure regulator? I remember reading somewhere about taking of the vac line off the regulartor, plugging it and checking the readings..

Thanks again,,:rockon:

 

Steve,

You can potentially isolate teh problem to either the injectors or regulator by monitoring the fuel pressure at shut down. If you carefully pinch the fuel return hose closed, that will prevent any fuel from returning to the tank through the regulator. If the pressure continues to drop, the likely source is injector leakage. If the pressure maintains, the regulator was probably leaking through (which normally wouldn't cause a rich condition on startup).

Another quick test is to remove the vacuum line from the regulator while the system is pressurized. If any fuel is spilling from the regulator vacuum nipple, the diaphragm is split and allowing leakage to the intake. You can perform that test with the engine running or off.

 

I've got the same exact problem and the only thing mentioned above that HAS NOT been replaced or checked were the injectors and the FPR. May be as good a place to start as any.

 

Quite an embarassing problem - especially at shows.
My fuel pump is only 5,000kms' old too - I read somewhere about a check valve failing to close and allowing fuel to escape back into the tank...can't be related to my problem though, I'm pretty sure I have fuel there - probably too much.