'91 100q 5 injectors replaced - now car wont start

[Steve B]

I believe that when the lifters have no oil the valve will NOT open as intended.  The situation I had heard about was somehow due to an overpressurization of oil in the gallery, which opens the valves prematurely (or may not ever close).  Could it have been due to some failure of a pressure relief valve???  I only have a very fuzzy recollection, and no BTDT, but I do remember that it could happen without opening up the engine.  

Steve Buchholz

Andrew Muff <andrew at muffster.com> wrote:

>+1 on the hydraulic lifters. I've done that myself. But it was during a head rebuild. If you let the oil leak out of the hydraulic lifters during a rebuild, you need to soak them in oil overnight to get them working properly. In my experience it's possible to get 1 or 2 of the valves to not work correctly. But unless you intentionally tried to remove the oil from them by squeezing it out, I highly doubt you would be able to get all 5 cylinders to not hold compression. 
>
>Since you didn't go anywhere near the valves, this is not a realistic cause in this case. 
>
>Andrew
>
>
>On Jul 2, 2013, at 1:36 PM, "Steve B" <urq at pacbell.net> wrote:
>
>> I have heard tell that there is a way for the hydraulic lifters to get pumped up in a way that the valves never close ... 
>> 
>> Steve Buchholz
>> 
>> ... and I second the comment that if a mechanic tells you they need to pull the head to figure this one out that you should shop for a new mechanic!
>> 
>> 
>> 
>> Huw Powell <audi at humanspeakers.com> wrote:
>> 
>>>> The mechanic told me that the engine is definitely shot but is
>>>> unable to diagnose it unless he takes the head off.
>>> 
>>> Whoever mentioned that the "mechanic" should find a new line of work was
>>> on the right track.
>>> 
>>>> I'm betting that the key sheared and the pulley no longer reads zero
>>>> with #1 at TDC.
>>> 
>>> Or the pulley shifted on the harmonic damper, either way, this is so
>>> easy to check.
>>> 
>>>> If that's the case, there is a slim chance that  the valves escaped
>>>> damage
>>> 
>>> Not really a problem.  This is not an interference engine.
>>> 
>>> The only way to lose compression on all cylinders from one "event" is 
>>> for the valve timing to be off (ignoring the washdown theory, which has 
>>> been tested in this case).
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