So i have been troubleshooting my 7 (S4 NA to turbo conversion) after a rebuild, and i have confirmed that i have spark and fuel, so now i am looking at my air/vacuum.
I can put my hand on the air inlet before the throttle body, and feel the pulsing of the cranking, but if i take any vacuum ports off and check them after the throttle body...on the UIM... you feel nothing.
My throttle body has already had the mod done to it and there doesn't seem to be anything sticking, so i am at a loss here.
Should there not be a strong vacuum presence on the UIM?
thanks

 

Yeah should be around 18hg or -8psi for a healthy engine at idle, probably a lot less when youre only cranking the engine. Its also normal for a fresh rebuild to have low compression. What the issue? Cant get it started?

Do a boost leak test. Make sure you dont have any leaks. You could also try a tablespoon of oil in each spark plug hole, its going to smoke like a **** tho

 

Bingo... I am having a hell of a time getting it going, but I have been pointed towards the timing being totally off and out of wack, so I will be troubleshooting that again, as I have already done the TDC process. I can get it right to that hump, but not over it to get it to start.

 

Definitely pull the CAS and restab it if you're have any question.