06 F250 5.4, low contribution on the right bank

YukonTyler · June 28, 2013

I have an '06 F250 in my bay. 65 000 miles on a 5.4 ..... came in running rough and check engine light on. p0316, p0300, p0303, lean bank 1 and rich bank 2.

customer requested plugs and a fuel filter prior to diag. did those - no change - and then went ahead with diag - power balance shows the entire right bank weak with the entire left bank strong. this all occurs at idle - no phasing of the cam shafts.

when left to sit and cold soak the engine has a rattle on restart - akin to tensioners bleeding down oil pressure. the noise is quite noticeable, and given the poor performance of the right bank i thought that it may have jumped a link on the chain due to a faulty tensioner. pulled the front cover and found the left tensioner blown out and very weak, but the right one to my surprise was good. changed tensioners, chains and guides while i was in there instead of doing just the bad one. timing was bang on before and after this part of the job.

left to sit and i still get the rattle on startup, and i still have weak contribution from bank 1 (though that was expected once i saw its tensinoer was good).

dropped the exhaust for giggles - no change to the right bank. i get the odd flatline on my upstream bank 1 02 sensor. i am going to play around there for my driveability.

any great ideas for either my rattle or my driveability? i'm going to start banging my head against the wall soon.

YukonTyler · June 28, 2013

more info ....

relative compression

1 - 1% down

2 - 5%

3 - 1%

4 - 7%

since it was like this before i did the timing chains and tensioners i don't think that i timed it incorrectly. soooo ..... broken locating dowel on the phaser? bad phaser? i wonder if that would be responsible for my perceived oil pressure leakdown and rattle on startup. ... multiple bad valve springs?

Jim Warman · June 28, 2013

Whenever you see one bank rich and the other lean put cats high on your list of suspects. Uncork your pipes from the manifolds, and see what you get.

YukonTyler · June 28, 2013

- that's where my gut went first jim. no change when i dropped the pipes earlier.

- i'm in the process of using the vmm to scope my cam signals. let's see if anything's off.

YukonTyler · June 28, 2013

Posted Image

^^^^ to see the images in thier full size: http://tpiwwp.com/out.php/i9214_camsoff.jpg

http://tpiwwp.com/out.php/i9215_scope.jpg

i think that's off just a bit. they should mirror each other @ 180 degrees.

i know that i put the chains dead on the marks - double checked before i put the cover back on. i wonder if i have a sheared dowel pin on the phaser or something like that.

Aaron · June 28, 2013

Whatcha got for base oil pressure on that animal on startup?

Crank end play? Wasn't there someone on here having some messed up mod motor issues and it came down to low oil pressure or something? I'm reaching here but can't quite put my finger on the original thread.

YukonTyler · June 28, 2013

i have seen crank end play on these, but usually that comes in to play with low oil pressure hot, and we all know that condition tends to manifest itself as phasers going crazy under load. in fact, the last one that i saw with slop the crank had bad main bearings @ 40 000 km - and again that showed up as bucking under load when hot. still, it's something worth checking. i'll put the pry bar and dial indicator on it tomorrow morning.

also, after my wonky bank 1 relative compression i did a manual compression on holes 2 and 4 .... got 200 psi after a four 'cranks'. that's plenty to fire.

the base oil reading will be interesting. i know that the pass side head is last in the line for oil pressure, but the fact that the running rough happens at idle lends itself to not being vct/oil pressure stuff.

*shrugs* .... more stuff to check i guess. i'm looking for ideas, so thanks for the ideas!