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Sep 2, 2011 | 12:34 AM

#16

Slick761

CF Veteran

Joined: Jun 2011

Posts: 2,858

Likes: 1

From: Nor-Cal

Year: 1990

Model: Cherokee

Engine: The venerable 4.0

Quote:

Originally Posted by rrich

Theoretically a higher voltage to the pump would make it spin faster - more pressure. BUT the pressure regulator would cut it back down.
All it really would do is shorten the life of the pump.

The pressure regular uses manifold vacuum, it's job is to maintain fuel pressure in the rail a set pressure above manifold vacuum.
the proper test -- compare fuel pressure in the rail compared to manifold vacuum. It should remain constant no matter what the speed or load.
If the hose leaks, or the regulator is defective, it will give too much fuel pressure - HI CO!

That's what I thought. Vacuum is good Iat coolant temp sensor good. Egr and egr solenoid good. O2 bad. I don't have a fuel pressure guage... its on my list of needed personal tools. I usually use the one at the shop I used to work at but its too far away. Advise replace o2 do tune up and oil change. Drive up to Santa Rosa and back. Retry.

Last edited by Slick761; Sep 2, 2011 at 12:38 AM.

Sep 2, 2011 | 12:34 AM

#17

DFlintstone

CF Veteran

Joined: Aug 2011

Posts: 10,489

Likes: 24

From: Nor-Cal Coast

Year: 90,84

Model: Cherokee

Engine: 4.0,2.5

I'm just not liking that on GP. I would bet it's ni-chrome. Unless the resistor is really physically mangled I don't get it over-volting.

Sep 2, 2011 | 12:38 AM

#18

Slick761

CF Veteran

Joined: Jun 2011

Posts: 2,858

Likes: 1

From: Nor-Cal

Year: 1990

Model: Cherokee

Engine: The venerable 4.0

Quote:

Originally Posted by DFlintstone

I'm just not liking that on GP. I would bet it's ni-chrome. Unless the resistor is really physically mangled I don't get it over-volting.

It is physically mangled lol

Sep 2, 2011 | 12:42 AM

#19

DFlintstone

CF Veteran

Joined: Aug 2011

Posts: 10,489

Likes: 24

From: Nor-Cal Coast

Year: 90,84

Model: Cherokee

Engine: 4.0,2.5

I know a guy, pretty sharp, says to check our rockauto..

Sep 2, 2011 | 12:43 AM

#20

Slick761

CF Veteran

Joined: Jun 2011

Posts: 2,858

Likes: 1

From: Nor-Cal

Year: 1990

Model: Cherokee

Engine: The venerable 4.0

Quote:

Originally Posted by DFlintstone

I know a guy, pretty sharp, says to check our rockauto..

Lol... I got him gettin parts there... hopefully well have this thing ironed out next week. And on the resistor output is 11.5... should be around 8 if I remember right.