2004 Liberty 3.7L high fuel rail pressure

[04Liberty#!]

Thank you
yes, probably not related, except for running the engine hard to test.
Should start a new thread for this?
Once resolved I can come back and finish this thread?

1st thing I thought I try, is, switch plug and coils on #1 and #2 cylinder to rule them out.
Plug gap on cylinder 2 was ~0.0375". I understand it should be 0.04. Close enough?
New plugs are Iridium BK6REIX-11, Old Plugs were Champion 3318.
I'm learning not to trust online lower cost parts.

Might be a week before I can get back into this.

Regards

 

[Intermechanico]

Thank you
yes, probably not related, except for running the engine hard to test.
Should start a new thread for this?
Once resolved I can come back and finish this thread?

1st thing I thought I try, is, switch plug and coils on #1 and #2 cylinder to rule them out.
Plug gap on cylinder 2 was ~0.0375". I understand it should be 0.04. Close enough?
New plugs are Iridium BK6REIX-11, Old Plugs were Champion 3318.
I'm learning not to trust online lower cost parts.

Might be a week before I can get back into this.

Regards

I’d leave it all here in one place. When we eventually get to the bottom of it, the relationship between failure modes will be helpful for others.

Good luck, keep your chin up.

 

[04Liberty#!]

Will do. Thanks!

Cleared P0302 codes.
Also cleared a P0113 (Intake Air Temp Sensor 1 Circuit High Input)

Swapped Coil and Plug from Cylinder 1 and 2.
Ran it with low reves just long enough, to get Engine light.
DTC P0302 indicates issue remains with Cylinder 2.

I will pick up an extension for compression tester and report back.

 

[04Liberty#!]

Update:

I: pulled the fuel Pump fuse and bleed off fuel rail pressure.
Removed #2 plug and coil.
Threaded in compression gauge assembly into #2 spark plug socket
Cranked engine; Pressure gauge moving between 120 and 150psi
When I stopped pressure held at 140Psi
Relieved pressure. Repeated and got same results.

I: Removed compression gauge assembly.
put a little oil in cylinder 2 through the spark plug port.
Reinserted compression gauge assembly into cylinder 2 spark plug port.
Cranked engine; Pressure moving between 140 and 150 psi
Cranked again and pressure moving between 150 and 170 psi.
When I stopped pressure held at 170psi

I: relieved pressure, did multiple very short cranks, until cylinder 2 pressure jumped.
removed compression gauge assembly, inserted long slender rod into spark plug port.
Marked rod where it lined up with dip stick.
With socket and rachet rotated crank shaft from under front of liberty,
a little at a time in both directions checking rod mark at dip stick to find TDC of Cylinder 2.
Pulled rod. Removed Shrader valve and gauge from compression gauge assembly.
Installed male air hose connector into compression gauge assembly hose, in place of gauge with on hand adapters.
Installed the modified assembly into Cylinder 2 spark plug port. Set shop air pressure regulator to 120psi, shut shop air valve.
connect shop air hose to modified assembly, slowly opened shop air valve.

I had a lot of air leaking from the #2 spark plug port and pressure stayed at approximately 100psi.
When I shut off the shop air valve pressure fell slowly to 30psi. Then stayed at 30 psi.
I then released remaining pressure, reconnected assembly to Cylinder 2 spark plug port and opened shop air valve.
Connection at spark plug port seamed good no leaks no sounds. Pressure held at 120 psi.
I listened to; exhaust, radiator fill port, head/valve cover, air intake, etc. and did not hear or sense any leaks.
When I shut the shop air valve pressure fell slowly to 30psi and stayed there.

I think:
170psi compression is in range, and # 2 rings are ok but should test all cylinders to compare.
Bleed test did not indicate other issue. Tapping noise at #2 makes suggested removing valve cover to inspect #2 rocker arms a good next step.

Thoughts?

 

[Intermechanico]

Update:

I: pulled the fuel Pump fuse and bleed off fuel rail pressure.
Removed #2 plug and coil.
Threaded in compression gauge assembly into #2 spark plug socket
Cranked engine; Pressure gauge moving between 120 and 150psi
When I stopped pressure held at 140Psi
Relieved pressure. Repeated and got same results.

I: Removed compression gauge assembly.
put a little oil in cylinder 2 through the spark plug port.
Reinserted compression gauge assembly into cylinder 2 spark plug port.
Cranked engine; Pressure moving between 140 and 150 psi
Cranked again and pressure moving between 150 and 170 psi.
When I stopped pressure held at 170psi

I: relieved pressure, did multiple very short cranks, until cylinder 2 pressure jumped.
removed compression gauge assembly, inserted long slender rod into spark plug port.
Marked rod where it lined up with dip stick.
With socket and rachet rotated crank shaft from under front of liberty,
a little at a time in both directions checking rod mark at dip stick to find TDC of Cylinder 2.
Pulled rod. Removed Shrader valve and gauge from compression gauge assembly.
Installed male air hose connector into compression gauge assembly hose, in place of gauge with on hand adapters.
Installed the modified assembly into Cylinder 2 spark plug port. Set shop air pressure regulator to 120psi, shut shop air valve.
connect shop air hose to modified assembly, slowly opened shop air valve.

I had a lot of air leaking from the #2 spark plug port and pressure stayed at approximately 100psi.
When I shut off the shop air valve pressure fell slowly to 30psi. Then stayed at 30 psi.
I then released remaining pressure, reconnected assembly to Cylinder 2 spark plug port and opened shop air valve.
Connection at spark plug port seamed good no leaks no sounds. Pressure held at 120 psi.
I listened to; exhaust, radiator fill port, head/valve cover, air intake, etc. and did not hear or sense any leaks.
When I shut the shop air valve pressure fell slowly to 30psi and stayed there.

I think:
170psi compression is in range, and # 2 rings are ok but should test all cylinders to compare.
Bleed test did not indicate other issue. Tapping noise at #2 makes suggested removing valve cover to inspect #2 rocker arms a good next step.

Thoughts?

Yep. Let’s get eyes on those rockers.