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Fuel Pressure Tests

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Old Mar 9, 2025 | 08:46 PM
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pizzaguy's Avatar
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Default Fuel Pressure Tests

There has been discussion on Facebook about what pressure the car should show and for how long after the key is off.

Here are two videos I made of my car, working fine, first one is a "engine start" test:
 
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Old Mar 9, 2025 | 08:47 PM
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Default Re: Fuel Pressure Tests

And a "No Start" test...........
 
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Old Mar 12, 2025 | 09:15 AM
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Default Re: Fuel Pressure Tests

What are we to learn from this?

Did you check pressure on no start after two hours? One day? How long does it take to drain back down to near zero?

I was fooling around awhile back with my car and it also showed no pressure after setting for a couple weeks. I think it is prudent if one has not started the car in a couple days to delay the key at point three (dash lights all on, but no start) for a few moments before turning the key to point 4 to engage starter. Thus giving the fuel pump a moment to run, build pressure before starting car. That should help prevent any rough idle or air entrapment at the injectors at startup.

 
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Old Mar 12, 2025 | 02:53 PM
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Default Re: Fuel Pressure Tests

I have a manual fuel regulator with no mods i set my pressure at 50 with mods 65 to 75.,,mine has an automatic return line and goes to 20 psi when i shut off the car , i aways turn on the key for 3 seconds for the fuel to build up,
never checked a stock except for running pressure and yes 59 to 60 is correct for the stock regulator
 
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Old Jun 9, 2025 | 09:25 AM
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Default Re: Fuel Pressure Tests

To add a bit more info on this subject I measured the pressure after one hour and it dropped to about 25 ~ 30 lbs. om my car which is running fine with no DTC. It will continue dropping to near zero as time passes.
 
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