Warm start long crank.


Jun 16, 2017
2009 335xi E90
Ok so here's the deal. About a month ago I started tuning on e85. Had long warm cranks from the start of e85. But they were about 3 or 5 seconds long. Then I upgraded turbos. I also replaced all o2 sensors and replaced the already index 12 injectors with new index 12 injectors. But now the long crank is starting to last longer. Long enough that I have to push start button twice because it doesn't start on first push.

I run MMP pi with bigger injectors. And i have dual walbro 450. One running off Hobbs switch. I got in the car and checked the psi on both pumps before starting. HpFP was around 80 something. And LPFP was around 72. As it is cranking I am watching the hpfp go up to 2300psi before it starts up.

The LPFPs are both new. The HPFP has about 5k on it max. I get the 2aae and 2aaf shadow codes but from what I have read it's normal. I am trying to find another point to start looking into.


Lieutenant General
Staff member
Aug 11, 2017
E89 Z4 35i, F10 535d
As it is cranking I am watching the hpfp go up to 2300psi before it starts up.
Someone else will know, but I'd have to check my car to verify - I would imagine this happens almost instantaneously, and one would not be able to watch it go up so-to-speak. Lots of slow start (and getting worse) posts in the past have pointed at the HPFP. But there have been others that have complained about slow starts on the N54 which have ended up being things like crank position sensors (post #3), and you might want to check your battery health (amperage specifically).