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Fuel pressure increases with engine temp

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I’m running a holley 750 double pumper with a n electric fuel pump and a holley pressure regulator. Have it set to 6psi but after 30 min of driving and engine temp of 190 it won’t restart and the pressure is climbing to over 10 psi. Regulator is hot to the touch and after it cools down it fires right up. Any help 😃

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  • 2 weeks later...

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If memory serves, Holly fuel regulatators need to be adjusted with the engine running. That is because electric fuel pumps are driven by voltage. When your car is running cold/at start up, the pump is getting 12V, but when you are driving the car around town, you should be producing closer to 14.3V, hence the fuel pressure goes up because the pump is pushing more fuel. So you need to adjust your regulator's pressure down with the engine running and the engine warm.

Hopefully that helps. Pontiacs can also have a heat soak hard/no start condition too. So let's try to fix your fuel issue first. If your hot no start condition persists we will move onto something else. I assume you are running headers too, correct?

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Yes I am running headers. I replaced the dead head fuel pressure regulator with one that allowed fuel bypass back to the fuel tank. This seemed to have taken care of the problem, and I also insulated the fuel lines. Took it out for about an hour and a half drive and no problems. That you for the input and I will stay in touch. 



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If you experience a hot no start, it is probably the starter absorbing too much heat from the wrap around headers. If that is the case, you will need to put some sort of heat insulation between the starter and the headers.

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I went with a mini starter so it does crank even after driving. It would crank over fine but no start as if flooded

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  • 7 months later...

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