Car won't start after warmed up Options

[Hammy]

This is continued from the NARP board a while back. I'm still having the problem so I'm posting here

This is a carbed (dual Weber) 1.7

It happens like this:

I drive the car around town, gets up to full temp, stop at a store to go in real quick, come back out a couple minutes later and turn her over...
Crank, crank, crank, crank. Doesn't fire up

This happens sometimes, and then sometimes it doesn't happen, just fires right up. (IMG:style_emoticons/default/confused24.gif) Also, the car starts fine and easily when the engine is cold.


I can't tell if it's fuel related.
I don't know if it's getting too much fuel when trying to start?
I usually turn the engine over, and step the pedal down half way and it fires up. When this no start problem happens, no matter what I do with the gas pedal it doesn't fire. Sometimes I can get it to fire by holding the pedal down all the way and cranking forever and it'll start and run at like 100rpm, really slow like a tractor. I usually try and lightly tap the pedal to get it going strong, sometimes that'll work and sometimes it'll die.


Then I can't tell if it's not getting enough fuel when trying to start -
Because If I turn the engine over and don't touch the gas at all, it won't start. I normally have to push the gas down half way for a normal start.

Or is it ignition related? Could incorrect timing cause it to do this? Dying battery? Engine seems to turn over fine. I have 12.4 volts across the battery posts with the engine off.

Or Vapor lock? My fuel pump is just below the hell hole.

Also, I've checked for any pinched fuel hose/lines and can't find any. I wouldn't think it was that because once the engine gets started again, it runs perfectly fine. I'm just scared to turn it off.

Any help MUCH appreciated. This is killing me.

[Twystd1]

Well.

Since the car does run and does start most of the time.

That (probably) rules out a bunch of things.

As far as having enough fuel... I bet you do.

Since you have carbs, and they have a built in reservoir (Bowl).
That pretty much rules out a fuel pump issue. As the car will start without the fuel line even hooked up to the carbs if the bowls are full.

So for the moment. Lets rule out the fuel pump.

You did say that you start the car with a half throttle snap. That makes sense. That pushes the accelerator pump on the carbs and pumps fuel into the combustion chamber to start the engine. I do that to on some cars.

So my guess is the same as some of the other fellas......

That is .. When you park the car and turn it off. The ambient heat from the engine is percolating into the carbs... And they are dripping fuel down the intake manifold and into the combustion chamber. And your spark plugs are getting wet from the RICH fuel mixture.. And VOILA.... The dam car won't start.
Cause it is FLOODED...!!!!

I B guessing that a good puff of smoke comes out of the exhaust when this happens and it eventually starts.... Correct?????

Try this next time to see if our theory is right. Next time it happens.

Try this starting technique.

Car won't start after a run. Floor the pedal... YUP.. I said floor it. This does two things.
1) The carbs pumps more fuel into the combustion chamber (bad)
2) Now the combustion chamber can get more air to change the fuel/air ratio to a much more lean condition. Then the little bugger should start. Just don't forget to take your foot off the peddle when it fires up. (IMG:style_emoticons/default/happy11.gif)
Ya see... With the throttle wide open. The carb will dam near STOP sending fuel down into the engine. Thats because the speed of the air going pass the transition ports will be so slow from the open butterfly's (creating less vacuum) . The carbs will send very little (if any) fuel on down into the heads. (We want that to happen)


Assuming this all works. (It might) You know know your carbs have the infamous "Slits drip"

Which simply means you need to rebuild and blueprint your carbs as best you can.

I think you have dual 32s... Am I right????? (cause I forget eveybody's setup)

ALSO: Like one of the other fellas said. If you have "Slits drip" (IMG:style_emoticons/default/blink.gif) in your carbs.

You can handily pull off your air cleaners when this happens. And look down the venturi. You will see what looks like raw fuel slightly dripping down the carb throat.

It only takes a little bit to flood an engine and make it hard to start....

Anyway... Thats my .02 worth.

Regards,

PS... Never ask me why they call it "Slits drip"... You don't want to know.

I can tell you it originated from the following.... (IMG:style_emoticons/default/sheeplove.gif) (IMG:style_emoticons/default/sheeplove.gif) (IMG:style_emoticons/default/sheeplove.gif)

C