CEL P0091 - Fuel Pressure / Hesitation under revs

Mitchyp

Mitchyp

Greenie N00B Member
Hi guys,
New member from Australia, I own a Mazdaspeed 6 - Autotech HPFP internals (6 months old), Accessport V3.
Running a Freektune.
Over the last few weeks I have been receiving check engine light code P0091 which points at fuel pressure sensor.
The first time with the code I changed my map back to the standard tune and the code seemed to go.
Just today I had the code again, but this time I had actual drive problems with the car hesitating and spluttering under normal revs, like it was misfiring.
(Side note: After 6 months of running my AP i've only just learned of the 'need' to run 1 step colder plugs and a smaller gap, so plugs will be changed to Denso ITV22's)

I checked my fuel pressure at idle and it was measuring around 3000psi, or not dipping below 3k.
Any ideas?
I was thinking of first replacing the sensor
Would anyone know the Bosch Fuel Pressure Sensor model code?
 
Hey just seeing this now, hoping you already have it fixed.

I'd recommend NGK over Denso. NGK LTR7IX-11 (6510): 1 Stage Colder Heat Range
NGK LTR6IX-11 (6509): stock heat range.

If you're Basically stock with just hpfp and a tune then stay with stock heat range especially if you're tuned for that just make sure they're gapped .026-.028" which is probably the gap Justin @ freektune sent you. That being said if Justin as your tuner is recommending swapping then absolutely do it.

As for your P0091, possible causes:

• High pressure fuel pump connector or terminals malfunction
• Short to ground in wiring harness between the following terminals:
- High pressure fuel pump terminal A-PCM terminal 2F
- High pressure fuel pump terminal B-PCM terminal 2G
•Spill valve control solenoid valve malfunction
•PCM connector or terminals malfunction
•Open circuit in wiring harness between the following terminals:
- High pressure fuel pump terminal A-PCM terminal 2F
- High pressure fuel pump terminal B-PCM terminal 2G
• PCM malfunction

Go through and check your connections something could have come loose, full shop manual with diagram and detailed diagnostics for each item is available in the metal member section (viewable after donation, we do this to pay for hosting the forums and raffles).
 
Do you ever find the solution? I have P0091 code and i'm lost, I have good fuel pressure readings from both fuel pumps, checked grounds, shorts, open circuit and nothing...
 
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