Four of the eight cylinders have no compression

Tiny
THOME9950
  • MEMBER
  • 2004 FORD F-150
  • 5.4L
  • V8
  • 2WD
  • AUTOMATIC
  • 200 MILES
Cylinders 1, 2, 3, 4 have 160lbs of pressure, but cylinders 5, 6, 7, 8 have 0lbs of pressure. Pull valve cover timing chain is fine no worn chain guides, cam is rotating when turn engine.
Sunday, July 15th, 2018 AT 12:46 PM

11 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,896 POSTS
Hi and thanks for using 2CarPros. Com.

First, if all four of the cylinders with no compression are on the same side, I suspect you may have broken one of the two timing chains in the engine. It is not common for this to happen, but it has. Now, if that is the case, the worse news is that this is an interference engine. Basically, that means there is no room between the pistons and valves if timing is wrong. If one of the chains has broken, chances are there are several bent valves which usually means the head needs replaced at minimum.

I have attached a picture for you to see how the timing chains run. You will see there are two, one for each side.

If you have other questions, let me know. However, if there is "no" compression (0), valves are stuck open or there is a hole at the top of all four pistons.

Let me know what you find.

Joe
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Monday, July 16th, 2018 AT 7:28 PM
Tiny
JACOBANDNICKOLAS
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I just realized you said the you have opened the valve cover and the chain is okay and the valves look good. The only other thing could be if the timing chain has jumped time and valves are partially open when the piston reaches TDC.

I am sorry I did not see that first.
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Monday, July 16th, 2018 AT 7:31 PM
Tiny
THOME9950
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So today I checked the timing chain guides they are unable worn but I noticed the cam phaser gear I off the mark. I am sending a picture so you can see.
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Monday, July 16th, 2018 AT 11:07 PM
Tiny
STEVE W.
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From the way that chain is setting on the left side of the sprocket I would say it has jumped time. The guides may be fine but the tensioner may be failing and let the chain move.
Only way to know for sure is to pull the front cover and set the chains in time and see if you get the compression back. I would also use a leak down tester on each cylinder to test for valve damage (likely) by gently rotating the crank and watching for the valves to close, then test. No reason to remove and install the new chains and parts only to discover that you need to pull the heads off to repair the valves.
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Wednesday, July 18th, 2018 AT 2:42 PM
Tiny
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I checked and all the valve are moving I looked in all four cylinders with a camera and all pistons look un touched could the pin on the back of the phaser be shear off causing the gear to move?
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Wednesday, July 18th, 2018 AT 4:00 PM
Tiny
STEVE W.
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Could be but I would still do a leak down test just to be sure. I have seen them look perfect but still have enough of a bend to leak. I have seen the pin sheared, also have seen the phaser itself fail and cause problems when it loses a couple pins.
Should be easy to see if you pull it apart.
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Wednesday, July 18th, 2018 AT 9:12 PM
Tiny
THOME9950
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Okay, I will do the leak down test first and go from there.
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Thursday, July 19th, 2018 AT 11:40 AM
Tiny
STEVE W.
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Would just not like to see you repair the rest and then need to tear it down. I know I do not like doing things twice. Especially timing chains. This engine is not bad compared to some but it is still a bother. Hope they all test good, then it is just a matter of getting the timing correct.
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Thursday, July 19th, 2018 AT 4:19 PM
Tiny
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Did a leak down test did go well air was escaping like it was over lashing. So I took the phaser off and it fell apart in my hand. All pins were broken but before I took it off I set the timing at TDC no1 piston all the way up and the timing lined up.
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Sunday, July 22nd, 2018 AT 12:02 PM
Tiny
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And the end of the cam got damage also.
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Sunday, July 22nd, 2018 AT 12:29 PM
Tiny
STEVE W.
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Looks like it started to get loose and tore things up. Not a big fan of that design or VVT in general as it seems to cause as many problems as it solves. The engineering is getting more complicated by the day.
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Sunday, July 22nd, 2018 AT 1:45 PM

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