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[cavell]

motor was not running when i got it. pulled heads. bent intake valves. cyl 3 had a major amount of black carbon crud. 1/16" layer on exh valves faces. cyls1-5 looked normal. almost no buildup. front head or 2-4-6 looked ok. talking combustion chamber appearance. i also noticed the front bank O2 sensor had a white buildup while the rear head sensor had a normal black sort of sooty look. coolant leakage? cracked block? cracked head? no i did not have heads pressure tested since it was a bad timing belt that was my main issue.

[Kevin Wood]

If it's just been rebuilt then expect the lifters to be noisy. They can take 20 minutes' running or more to quieten down.

[Marks DTM Calib]

After the valve replacement did you check the valve seat seals with a bit of liquid in the combustion bowls?

Also, the fact that one of the cylinders was showing fouling may suggest a weak spark and poor combustion.

As Kevin said, it can take a while for the lifters to fill following head work.

[cavell]

thats true. what happens in cylinder? fuel is injected and spark ignites it. too much fuel and/or weak spark can work together or independently to cause the issue. does cyl also have good compression? i cant really verify ring condition unless i do a leak down test. i got vue as a flip. fix obvious issues. i didnt feel like putting in a rebuilt motor.

[Marks DTM Calib]

So from personal experience of this power plant (not that I know much..... )...

The blocks are pretty bulletproof and the heads plus block don't suffer overheating issues.
I am yet to see a cam belt failure result in only 12V to be damaged......
As per all petrol engines, they are sensitive to poor or failing coils packs, not as noticeable as many engines due to the six cylinders so can be a possible. (early engines had DIS and its common on reassembly for the leads to be connected wrongly but later are coil per plug)
To much fuel is very unlikely (given the operating method of the engine).

[cavell]

Started vue this afternoon. It purrs now. Clatter sound is gone. With 100% new exhaust, vue is so quiet. So, how do you verify weak spark on cyl #3? I have no misfire codes. But combustion chamber looked bad when I pulled head. Should I just try another coil to be safe?

[Marks DTM Calib]

You need a test plug to try the coil whilst its disconnected from the plugs, at atmospheric pressure you should be able to get a spark of 35mm+. You could rig something up to do this also, if its 20-30mm max the coil pack is getting tired.

[cavell]

my vue use the 3+ coil pack for each bank. i do not know what the test procedure is for these types of coil packs. another tech says my heavy carbon/crud residue is probably due to bad rings on that cyl.

[Kevin Wood]

It's very rare to get any bottom end problems / wear at all on these engines, unless the piston ring top groove has been crimped by valve to piston contact. Does it burn any oil? I'd expect consumption to be considerable if there's sufficient getting by the rings to cause a noticeable issue in the combustion chamber.

Might be worth pulling the plugs after a decent run to see if there are still signs of a problem there?

[cavell]

i bought the vue for parts really. new exhaust and tires. i wanted to see if i could fix the heads actually and move on. i only plan on driving it to verify it is fixed. 1-2 weeks than its gone

[Marks DTM Calib]

my vue use the 3+ coil pack for each bank. i do not know what the test procedure is for these types of coil packs. another tech says my heavy carbon/crud residue is probably due to bad rings on that cyl.

Heavy crud might be but, a carbon coating is generally poor combustion.

Plus this power plant has little issue with rings etc.