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Fuel pressure!


78 280zcar

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I'm not versed in Z EFI but I do know GM EFI very well. 30 psi at idle should be okay. The manifold vacuum is probably used to control fuel pressure at the injectors at any given rpm/load. If you gun the engine the fuel pressure should rise upwards to the 37-38 psi and then settle back down to 30 at idle again. When accelerating or cruising at high rpm's the fuel pressure is probably in the max range. A fuel pressure gauge in the cockpit would prove this. As a side note, NEVER run fuel lines into the cockpit for ANY reason! Only use an appropriate isolator! Fuel pressure dropping (it should hold for a few hours anyhow) quickly once the engine is shutdown is caused by one of three things, a bad check valve at the pump, a leaking injector, or an external leak. The last would be very obivous....

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I dont mean to be a dumb a--. But how do I do that pressure leakdown thing?

I'm just referring to the same test you've been doing. Check the pressure while it's running and then turn it off and see if it holds. But using the adjustable regulator since from what I understood, it ran at 40 psi. Just adjust it down to the factory spec.

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