Jim : First verify the engine compression is even on each bank of the engine. If the compression is off verify the camshaft timing is correct. This has 3 timing chains, verify the correct make and links are used when setting up the timing. If the engine is mechanically good, verify the crankshaft sensor signal and the camshaft sensor signal is correct and not erratic. The crankshaft sensor is on the front of the engine and if the crankshaft sensor teeth were damaged from the engine work it may have erratic spark and crank over like its out of time and idle poorly.
Jim : Base on what you have said it sounds like the timing chains are not installed correctly.
Customer: Funny thing is, when it first starts, it runs well for about 30 seconds.
Jim : Then looking at the camshaft and crankshaft sensor would be highly recommended. From everything you have said it definetly sounds like the timing chains were not correct the first time and I am pretty sure they aren't going to be right the second time unfortunately. Was this done at the a dealership or independent shop?
Customer: independent shop. sad thing is, I've known this guy for 40 years and he's always done right by me. starting to sound like he was in over his head at the start. I have a feeling he knows now what he did wrong. this was my worst fear.
Jim : Do you have a dealership near you?
Customer: yes, he has consulted them and assured me they gave him guidance. Could he have destroyed this engine or is it just amatter of redoing?
Jim : I don't want to jump to any conclusions on damage, I would take it in to the dealership and have a diagnostic done.If it is related to a faulty repair then I am sure he will pay to fix it.
Customer: Well, obviously not what I wanted to hear, but thank you for the unbiased info.