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Discussion Starter #1
After driving the car and shutting it off the car will not restart for at least 1/2 hour or more. The car will then start and drive fine.

Looking for ideas to fix this problem.

Thank you,

Orson
Long Beach, CA
71 240Z
 

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Classic vapor lock and percolated fuel.
The heat from the exhaust basically is boiling the gas in the fuel bowls ‘percolating ‘ and lines. So there a just bubbles or gases and the fuel pump can’t push it to the carbs either.
If you notice 260s had an auxiliary electric pump to help pushing cool fuel from the tank.
Also you will notice early z’s have a heat reflecting insulation on the fuel lines.
I bypassed the stock ‘puller’ pump mounted on the head running off the the cam.
I use an old quiet cheap Mazda rx7 pump below the gas tank to push the fuel.
It has worked with SUs and Mikunis. With the heat of headers.
Additionally I added the fan that a lot of ZXs had that mounts to the engine and blows air over the cam cover onto the intake and exhaust. A heat shield above the exhaust manifold helps too
 

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Discussion Starter #4
Classic vapor lock and percolated fuel.
The heat from the exhaust basically is boiling the gas in the fuel bowls ‘percolating ‘ and lines. So there a just bubbles or gases and the fuel pump can’t push it to the carbs either.
If you notice 260s had an auxiliary electric pump to help pushing cool fuel from the tank.
Also you will notice early z’s have a heat reflecting insulation on the fuel lines.
I bypassed the stock ‘puller’ pump mounted on the head running off the the cam.
I use an old quiet cheap Mazda rx7 pump below the gas tank to push the fuel.
It has worked with SUs and Mikunis. With the heat of headers.
Additionally I added the fan that a lot of ZXs had that mounts to the engine and blows air over the cam cover onto the intake and exhaust. A heat shield above the exhaust manifold helps too
Thank you so much for your reply and information. I really appreciate it. I'm looking forward to fix the problem.
 
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