help checking fuel pressure

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Mar 28, 2011 | 07:31 PM

phlounda

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From: Whitman MA

help checking fuel pressure

How do i correctly check fuel pressure in my 87 coupe?
I have a fuel pressure tester.
What are the correct pressures?
What should I see on startup versus acceleration etc?

Thanks
Ed

Mar 28, 2011 | 08:14 PM

Bucs34

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First off, itll be handy to have a tester with a decent length hose on it to tape the gauge on your windshield to monitor pressure while driving. There will be a metal cap (looks like he cap on a bike tire) I cant remember exactly where it is but I want to say its on the passenger side towards the back of the fuel rail. Once you find that cap, unscrew it and then attach the fuel pressure tester to that nipple. You want to look at the pressure in a few different situations.

-key turned to the accessory position but car still off
-idle while cold
-idle while warm
-while driving under load (this is where tape comes in handy to attach the gauge to the windshield)

I forget the exact psi readings you should get but Im sure someone else can chime in with that. Hope that helps some!

Mar 28, 2011 | 08:18 PM

Bucs34

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From: None None

This is what I was looking for! The link to my fuel pressure testing experience. I have an 85 but most if not all the info should help.

http://forums.corvetteforum.com/c4-t...s-in-gear.html

Mar 29, 2011 | 08:28 PM

redrose

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From: backwoods upstate ny

should show abt 40 psi with eng not running (only 'abt 40' , most gauges do not come 'calibrated' when new, if you have a 'laboratory service' gauge we can talk in specifics)...after 12 hour sit, should still show 10 psi min (further drop may/may not indicate a big problem)

pressure should remain the same under load.

when the gas pedal is depressed (eng running) the pressure should INCREASE.

Mar 29, 2011 | 09:40 PM

phlounda

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From: Whitman MA

Thanks guys.

If the pressure decreases?

Fuel pump?
pressure regulator?

Ed

Mar 29, 2011 | 09:54 PM

Bucs34

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My problem with fuel pressure ended up being the pump. My fuel pressure was fine until I tried to accelerate hard. Replacing the fuel pump is very easy! It all comes up out of the tank through the fuel fill neck. Just have to remove the fuel door and it comes out that way.