Should fuel pressure regulator hold vacuum?
Thread Starter
Racer
Joined: Sep 2001
Posts: 266
Likes: 7
From: Sumner WA
Should fuel pressure regulator hold vacuum?
I'm diagnosing some strange idle problems and one of the things I did was put a mighty vac on the fuel pressure regulator vacuum line. When I pumped the vacuum once it very quickly went back to 0. Is this normal or is the diaphragm needing replaced? I don't have gas coming out of it when I run with the vacuum line disconnected.
I instaled an adjustable fpr about 7 years ago but reused the diaphragm.
It's an 88 L98 with 186k miles.
Ron
I instaled an adjustable fpr about 7 years ago but reused the diaphragm.
It's an 88 L98 with 186k miles.
Ron
Safety Car
Joined: Dec 2008
Posts: 3,588
Likes: 10
From: North New Jersey
I am not completely sure but I think that it should not hold a vacuum. If the vacuum line is disconnected then it should lose all of the vacuum it built up. Maybe you have leaky injectors causing a strange idle???
Race Director
Joined: Apr 2003
Posts: 17,697
Likes: 1,666
From: moraga ca
If your MityVac line going to the vacuum pump is not leaking and you are losing vacuum, then the diaphram must be bad. No air should leak around the diaphram. If you take it apart, you will see how it is a sealed unit and should hold vacuum
Thread Starter
Racer
Joined: Sep 2001
Posts: 266
Likes: 7
From: Sumner WA
That's what I was thinking. Thanks.
