Do a compression to rule out any mechanical problems. A few months back we had an old VR6 which the owner was no timely on oil changes and the engine was sludge up and the oil pump was partly plugged which inturn seized the cams in the head... need I go further. If there is no or low compression it can only be two things: 1-timing chain problems 2- seized cams & #1.
The car: 93 Passat Wagon GLX VR6, 150k miles
>
> Yesterday the car was running like a top.
>
> This morning I started it, and it growled for a few seconds, like when
> there isn't enough oil getting to the hydraulic lifters, although I
> don't recall it ever being that loud before. But it only lasted a
> second, and then it was fine.
>
> Twice later in the day I started it, and the same thing happened, and
> it went away after a few seconds, just as before.
>
> Later I was driving on the interstate and it was running just fine,
> all signals go, no blinken lights, water & oil temp fine. I pulled off
> at a store. Came back out, when to start it. It growled, stumbled,
> stalled, and then refused to start again. When I crank it, it sounds
> sounds growly at first but the quiets down a little as it cranks.
> Sometimes it almost sounds like it's about to start, but only for a
> second, then it sputters and dies.
>
> Under the hood I found the following potential culprets:
> 1) Vaccume hose missing plug. Actually it had been missing that plug
> for weeks, but I plugged it to be safe.
> 2) Breather hose heater wires broken. I cobbed them back on.
> 3) The hose from the evap carbon canister to the throttle body was
> melted halfway through and stuck to the exhaust manifold heat shield,
> since it had popped out of it's little hanger. I pinched the intake
> end shut with pliars, but it still didn't start. It may have sucked in
> some melted hose, dunno what that might do to the engine. Could it
> prevent the valves from closing fully?
>
> I tried pulling codes out of the engine, but it only threw codes for
> the engine speed sensor and hall sender, which it always throws when
> the engine isn't running.
>
> I did go through somewhat carefully to check that all the major
> components weren't disconnected, like the MAS and the throttle
> position sensor, etc. None of them were. It just strikes me as odd
> that it went from running fine to just not starting, all of a sudden. > Any clues?
>
> Best regards,
> Jeff