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vacuum and fuel pressure specifications.
Posted: Tue Mar 29, 2022 7:35 pm
by Bookworm
I'm having a hard time tracking these down. I'm seeing 38-44 PSI for fuel, but zip for what the vacuum should be at idle (to check for vacuum leaks)
Re: vacuum and fuel pressure specifications.
Posted: Wed Mar 30, 2022 12:21 am
by jolt
Here, this link may help explain things about engine vacuum:
https://www.motor.com/magazine-summary/ ... uum-gauge/
There are so many things that can effect vacuum, like altitude, camshaft timing, exhaust systems, etc... that manufactures have not listed vacuum spec's for decades now.
Re: vacuum and fuel pressure specifications.
Posted: Wed Mar 30, 2022 4:48 am
by joatmon
The 03 Matrix manual (attached) says fuel pressure of 44-50 psi at idle, but I can't find anything about measuring vacuum.
Re: vacuum and fuel pressure specifications.
Posted: Wed Mar 30, 2022 9:18 am
by Bookworm
Automotive engineers (and companies) drive me nuts.
It's another round of "It's a vacuum problem". "Okay, how do you know?" 'we just do'.
Determine vacuum problem: How, measure vacuum at different areas with things blocked off. What's it supposed to be? "Oh, we won't tell you. We just know".
Re: vacuum and fuel pressure specifications.
Posted: Wed Mar 30, 2022 7:07 pm
by Bookworm
I think I'll hook up my Mityvac to one of the vacuum lines and use that to give me some pressure readings.