This 2006 Mazda 6 idled just fine, but the 2.3L turbo engine barely performed and exhibited poor power output under cruise and acceleration. The same DTC seemed to show up, but never at the same time as any driveability concern.
Motor Age Technical Editor Brandon Steckler and the technician keyed in on an analysis of PIDs. Get reacquainted with the details of the Mazda 6 here.
Steckler asked fellow technicians to choose from one of four options:
- Reset camshaft timing and re-evaluate
- Inspect camshaft/pump condition
- Condemn FVR (HPFP assembly)
- Condemn HPFP piston/chamber (HPFP assembly)
For those of you who chose answer No. 2, congratulations!
Answer No. 1 is incorrect. Even though cam timing has a drastic effect on HPFP output, the late intake cam timing would’ve yielded higher-than-commanded rail pressure. Answer No. 3 is incorrect as the FVR has been proven to be functional through voltage and amperage testing. Replacing the FVR (HPFP assembly) would make no change to the symptom or data collected. The answer could certainly be a possible fault and the likely cause of the zero HPFP-output. However, we cannot condemn the HPFP until visual inspection of the cam lobes and pump drive has been made. The HPFP was removed, and the intake camshaft was found to be broken at the pump drive cam lobes, preventing the HPFP piston from stroking (Figure 1).
Be sure to keep reading Motor Age for monthly diagnostic challenges, and the answers that solve the problems.