does this sound like a valve timing issue?

[kunar]

i've have been having problems for a while with my truck. it slowly (month or so) went from normal, to bad mpg/low power/fuel smell, to dead on the road, wont start. after doing a quick compression test i have about 30 psi on cyl #1 and less than that on cyl #3 and #4. i didnt check the other three yet and i wont unless i have to but my best guess is that my timing set has slipped or broken and caused this issue. i had to do a timing set about 6 months ago after the little tooth sheared off of the bottom gear leaving me with similar compression test results. sound like im on the right track?

 

[kunar]

pulled the timing cover, nothing looks out of place. i cranked the engine over and the timing marks line up, nothing has slipped or skipped. anybdoy have any ideas? broken cam shaft???

 

[rickcdewitt]

throw a little oil in and check to rule out the rings

 

[kunar]

throw a little oil in and check to rule out the rings

i thought that too since its been sitting but i should still have more than 30 psi even if it was bone dry, right?

 

[IMenriched]

i thought that too since its been sitting but i should still have more than 30 psi even if it was bone dry, right?

Are you trying to turn this over by hand to get this compression reading? or using the starter?

That would my thought as well "more than 30 psi"...should be some where around 100psi. very healthy is more than that.
so... it is either leaking past the rings, or valves, or out a crack in block or head or the head gasket. possiblity of broken valve springs, or bent valve rods too. you can see that the list gets large quick. concidering that the 2.9 heads are a problem area...well you get the picture.

I'm sure others here will be able to give more info as to how to ascertain where is it leaking/loosing compression with readings form a compression test.

putting a spoon full of oil in each cylinder prior to compression test couldn't hurt.

If your confident that valves ,head and pistion/rings are reasonably solid ...maybe you've lost the roll pin in the distributor gear.

hope that helps

 

[rickcdewitt]

i thought that too since its been sitting but i should still have more than 30 psi even if it was bone dry, right?

the point of using oil is to check it dry then with oil.if it improves you know that rings are at least PART of the problem.