How to test the fuel pressure (Page 1/1)
danahart MAY 29, 05:58 PM

{EDIT}
Problem solved. I found the autopart rental gauge was broken. I borrowed a different one and it works.



Hi guys, I have no idea what I'm doing wrong here but I expect it is something simple. Background - I'm new to Fiero and car mechanics in general but trying to learn and using the Fiero as my classroom...

I need to test the fuel pressure in my v6 1988 Formula. I borrowed a fuel pressure test kit from the autoparts store and found the test valve. I don't think I need any of the adapters, so am using the valve end attached to the gauge. I thought it was just a simple screw it on and it shows the pressure. But when I get it on there, nothing. Started the car, still nothing. If I poke the stem inside the pressure valve, gas squirts out so I assume it is under pressure and should show something. So, based on that assumption, I must be using the gauge wrong. But it looks so straightforward I'm stumped as to what I'm doing wrong. See photo attached of the end I'm trying to screw onto the test valve. Maybe I need one of the adapters but none look like they would work.



[This message has been edited by danahart (edited 05-29-2024).]

Patrick MAY 29, 06:33 PM
It's been quite awhile since I've tested the fuel pressure on my Fieros, but from what I recall, you don't appear to be doing anything wrong.

When screwed on, the fitting needs to be pushing down the center pin of the valve. Within reason, are you tightening the fitting down all the way? What is that beside the valve that appears to be getting chewed up?

[This message has been edited by Patrick (edited 05-29-2024).]

danahart MAY 29, 07:41 PM
Found out it was a bad gauge. Different one works. Thank for the reply!


quote
Originally posted by Patrick:

It's been quite awhile since I've tested the fuel pressure on my Fieros, but from what I recall, you don't appear to be doing anything wrong.

When screwed on, the fitting needs to be pushing down the center pin of the valve. Within reason, are you tightening the fitting down all the way? What is that beside the valve that appears to be getting chewed up?


[This message has been edited by danahart (edited 05-29-2024).]

jumpmonkey JUN 04, 01:25 PM
A somewhat redneck way to test the pressure is to see how far the gas squirts up when you release pressure via the schrader valve. Prime the fuel pump 2-3 times and then stick a screwdriver into the schrader valve. It has to be one quick motion, or you won't let out all the pressure at once. If the fuel shoots up 5-6+ inches, you have good fuel pressure. Not an exact measurement by any means, but enough to move on to solving other fuel related issues, from my experience.

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Jumpmonkey