the valve can burn if it does not seat properly and exhaust gasses make it past the seat, in that case it can also damage the injector. to give you an example, if the seat was not machined "in-line" with the valve guide then it would not seal, gasses would make it between the valve and the seat and cause the intake valve to overheat and possibly bend. It can also be the other way around too like yous say if the injector is bad and the gas temps go too high in the chamber. Until they take off the valve to check the seating side would be hard to tell, in most cases you see a section of the valve being burned off which is not your case.
Well, this got me thinking...
I DID NOT have any injector problems until after I added the new/re-manufactured cylinder head. Two days into running the engine with the new head, things went bad. None of the injector codes showed up until that point. Immediately prior to replacing the injectors, I was getting a code for P0201, P0202, P0203 and P0204. Again, no problems with the injectors before the head switch.
Compression check yesterday showed zero compression on # 4. The remaining cylinders had acceptable compression when turning the engine over with the fuel pump relay removed. I then connected my shop compressor tank (leak down test) to the remaining 3 cylinders @ 110 p.s.i. and heard a hissing sound coming from every single cylinder. I did this with the rocker arms removed so as to ensure all the valves were indeed shut. Still, air escaped.
This isn't cool and at this point is costing me a boat load of money.
