Hard Starting, Take Two
 

As a follow up to my earlier post on the problem (2011 MS3, 91000 miles, stock), I replaced the plugs, ran a couple of tanks of "good" gas through, and I still have sporadic long crank times before the car fires. Sitting in the heat (90 plus every day in Georgia) seems to be a part of the problem, but there's no clear pattern. Is there a check valve in the fuel system that's designed to hold pressure after shutoff? Can fuel in the line be evaporating due to temps? Once started, the car runs fine, pulls strong to redline, and isn't showing any codes.

If you've tried all the log fuel pressure after turning off the key stuff, then I would check the HPFP connector to make sure it's tight, look for signs of leaks, etc. Just for the heck of it, you might remove your spill valve and clean/inspect it.

Sounds similar to my issues I had years ago: http://www.mazdaspeedforums.org/foru...ml#post2486931

Here are the symptoms I had:
- hard starts when warm (45 min, up to 2 hours after being turned off from being up to temp)
- Vacuum at idle on my external boost gauge was reading -15 to -18 PSI.
- AFR at idle fluctuating between 14.2 - 15.2
- More knock than usual


The issue ended up being my EGR valve was dirty and didn't fully close which caused all the issues. I then did the EGR bypass and the car fired right up every single time.

Exact issue I had on my 2011 with ~65k miles. EGR valve was stuck, so I did a bypass and lived happily ever after.

OP, definitely consider this. The EGR can be cleaned, but you'll want to remove it from the car to do so. Not a big task by any means.