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Vapour Lock


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Has anyone had really bad Vapour lock on there 240Z. I cannot drive the car if it is over 28 Deg C. does anyone have any ideas on how to fix this. My car is stock.


1972 240z

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i started to get it the other day when my car was running hot, turns out the fuel line was resting against the bottom radiator hose AND my fuel filter wasnt flowing well enough.

adjusted the line so it wasnt sitting against the rad hose and bought the biggest filter i could find and it solved the problem.

the more pressure you can get in your lines the less chance vapour lock will happen. if you have a mechanical fuel pump that wont help to much either.

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Here is a link on the site that explains it and does lead to some retification ideas.

I know it is common on the Zed's (mine does not have the problem though:D ) as you can see a lot of people using relfective tubing to prevent the heat issue.



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I've never been a fan of the mechanical fuel pumps used on the L Series motors. It seems every single one of them I've come across leaks fuel or oil (or both) ....

I think it was about 2 months after I bought my 240Z that I fitted a Carter low-pressure electric pump to the car. (Which is now the priming pump for the EFI system)

All that aside, check the lines & filter for blockages, also - is the stock heat shield installed?

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Check the fuel rail and line to see that it is not in contact with the engine or as brett said not against the water hose. In stall a electric pump, the factory did this starting in '73 . your car is wired already for a electric pump back by the tank where the fuel line comes from the tank you will find the wires rolled up and taped. I installed a pump from a RX-7 they work great and are cheep at the bone yard , just make sure that it is from a carberated car NOT FUELINJECTED.:classic: this should cure vapor lock.

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  • 3 weeks later...

I have had a Electric fuel pump put in and heat sheilding on the fuel lines under the bonnet. I got a factory heat sheild and had that put back on. I hope this gets rid of the vapour lock problems. Thanks guys

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