Take what you want from this.
Okay, So quite some time ago I mentioned the car was stumbling in the top end. I merely blamed it on three possible reasons and they were; crap fuel, crap intake and the possibility of having a dirty Air sensor. Alas it was neither of these. In fact it is actually the fuel pump not being able to support the need of fuel the engine longs for.
This pinching/choking whatever you want to call it never went away. That said it never occured on a consistant basis. Car would choke occasionally, mainly around 5000-5200RPM. The feeling is like it is hitting the rev limiter except that isn't where the limiter is.
What most of you probably don't know is that there was a TSB (technical Safety Bulletin) released in North America, Mexico and Canada detailing the following;
Applicable Models:
2007-2008 MS3
2006 -2007 MS6
2007 -2008 CX7
Description:
- Rough idle, stall and/or hesitation under cold conditions
- Intermittent lack of power during accleration when engine is hot.
- MIL turns on DTC P2177/P2187 (fuel system to lean at off idle)
caused by;
1: The drive of current PCM is not enough for some fuel pumps.
2: Some fuel pumps have slower response.
Models with build date prior April 2007 require warranty vehicle inquiry using eMDCS system and COMPLETE REPLACEMENT OF FUEL PUMP.
Full TSB Report
The DH log below shows the issue perfectly. A log showing 1600-1700 on FuelPresDI is a good pump, anything less is a faulty pump!!
NOTE: FAULTY!!!!!
For the benefit of all of you that have mods and access to a dashawk PLEASE log your fuel rail pressue. No matter what mod or ecu option.. IINCLUDING THE XEDE BOYS!!!
Due to the CDFP not being able to deliver the amount of fuel required, the PCM limits the amount of boost to correct the air drawn into the engine. This ensures that the PCM maintains a correct AFR. At no point, does the AFR go lean. Power is sacrificed, in order to save the motor from a lean mixture.
Mazda Australia are aware of this issue, they simply have done nothing about analysing the CDFP but rather have just provided a PCM update that does NOT rectify the issue. It merely clears the stutter and provides more hesitation.
I really want people to be aware of this issue, modifications or not!!! tune or not!!!
Wayne and the guys testing this tune are very aware of this issue. It is likely they will log cars before a tune to ensure they are suitable. Also, Wayne is likely to import kits from the USA to modify and uprate the CDFP.