Could be a plugged cat?

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Jul 1, 2012 | 01:22 AM

#16

88cherokeepyles

Thread Starter

Junior Member

Joined: Apr 2012

Posts: 92

Likes: 1

From: Portland, OR

Year: 88

Model: Cherokee

Engine: Inline 6 4liter

88

When I take the vacuum hose off of the regulator, it is supposed to go up- I notice no change. What may be up with that? There is noise (hissing) when I take it off, which means I think that it is still doing its thing, but I see no change in pressure. I'm getting 20 steady but it shakes up and down violently, and also drops to 12 ish when revving.

Jul 1, 2012 | 12:42 PM

#17

Parsnip

CF Veteran

Joined: Dec 2011

Posts: 1,050

Likes: 2

From: Roanoke, VA

Year: 1990

Model: Cherokee

Engine: 4.0

Have you checked the relay/fuse already?

Jul 1, 2012 | 09:58 PM

#18

Radi

CF Veteran

Joined: Apr 2012

Posts: 5,302

Likes: 23

From: Wisconsin

Model: Cherokee

Quote:

Originally Posted by 88cherokeepyles

88

When I take the vacuum hose off of the regulator, it is supposed to go up- I notice no change.

It can't go up if the fuel pump isn't providing any more pressure. It can only rise to what the fuel pump supplies, which in your case appears quite low.