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Residual fuel pressure?

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Old Apr 24, 2023 | 03:59 PM
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Question Residual fuel pressure?

Having fuel issue. I should have residual fuel pressure that SLOWLY over a few minutes returns to zero after I turn the car off, correct? ...It's a GSL-SE

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Old Apr 24, 2023 | 07:42 PM
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Car keeps flooding and won't hold fuel pressure after shut-off, which makes me think stuck injector.
I have spark and air..

Gonna do FSM injector service procedure next.
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Old Apr 26, 2023 | 10:54 AM
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Injectors are fine. Not stuck open and not leaking.
They're both at 2.2 Ohms and actuate with 12v.
I could blow thru them when activated so not clogged.

Still need to check continuity between trailing coil neg ignition terminal and U terminal of ECU.
Main relay clicks when ignition turned so EGI main link is good.
Car won't run so i can't listen for the injectors actuating :/
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Old Apr 26, 2023 | 12:13 PM
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From: https://www2.mazda.com/en/100th/
Originally Posted by Johnny_Cracker
Car won't run so i can't listen for the injectors actuating :/
you could plug in a distributor, and spin it by hand, it should then fire the injectors
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Old Apr 30, 2023 | 03:30 PM
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Cool. I'll give that a shot if this comes up again... I ended up securing them to the fuel rail and had the wife crank it a few times. I got equivalent simultaneous pulses of fuel from each (which I'm assuming is normal. I was expecting them to be staggered so learned something new there..) I also checked continuity between trailing coil neg and ECU terminal U and do have continuity so am assuming the injectors are fine at this point.

As for the loss of fuel pressure I've found it's definitely coming from the rear somewhere on the supply side. The FSM (page 4B-62) shows a "ventilation and check valve" on a separate line from the main fuel supply line. Is this what maintains pressure when the pump is off?

Last edited by Johnny_Cracker; Apr 30, 2023 at 03:31 PM. Reason: typo
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