5.4 3v Engine Noise, Misfire Codes

[blown99]

2005 F-350 5.4 3v.

Came in with codes p0340, p0300, p0303 p0304  

Customer had it elsewhere and told him the phasers were bad due to the p0340 code

The phaser is not making any noise until it is up to temp.  Cylinder balance shows a cyl 1 and 5 a bit on the lower side.  Relative compression shows #3,4 down around 15%.  Cranking is uneven.  My question is, can a cam phaser cause the compression to be low in a cylinder?  I have yet to check base engine oil pressure.  Engine has 95k on it, truck is well worked.

[8WA Sman]

I would check base oil pressure then go from there. I can't think of a way cam phasers would be the cause of uneven cranking.

[jw33]

Usually if a phaser is causing timing issues it affects whole bank not just 2 cylinders

[forddieseldoctor]

I would check base oil pressure then go from there. I can't think of a way cam phasers would be the cause of uneven cranking.

 

I've seen it. But the root cause was low oil pressure. The oil pressure dropped while the pin was unlocked and it was unable to lock the pin. Truck ran horrible and when I went to restart it you could hear that the compression wasn't right.

[blown99]

Well, the base oil pressure was low.  Down to 20 psi  at 150 degree oil temp.  You can here the rod bearings clattering around just after start up.  

[jw33]

Thought spec was 15 psi hot

[forddieseldoctor]

Spec is 15.

[sneakypete]

but you need at least 25 psi for proper vct operation.

[jw33]

Can't remember part number but thought I read the new vct solenoids were made to operate at 15 psi that's why spec was lowered to 15

[sneakypete]

that could be. I haven't heard that. very interesting.