ISX15 cm2350 Gear(Lift) fuel pump

[mmssvv]

Hi everyone.Is there any check valve or pressure regulator on this pump to be checked?
When measuring gear fuel pump pressure I see fluctuation.This fluctuation is worse under driving condition and hi rpm 1400-1600.Engine run rough and no power.What can cause this?Fuel system primed,no air in return line and no inlet restriction.No fault codes.
Thanks in advance.

[Rawze]

As far as the main fuel rail pressure is concerned...

How much it is allowed to fluctuate,.. I do not know, but I do know it is normal to go up and down by quite a little bit.

It is normal for the pressure to fluctuate. It is a bypass/charging circuit system with an accumulator, meaning it will charge to a certain pressure,.. bleed off as the fuel is used,.. and re-charge when if reaches a minimum pressure that makes the pump kick back in and top it off again.

[mmssvv]

(01-11-2017 )Rawze Wrote:  How much it is allowed to fluctuate,.. I do not know, but I do know it is normal to go up and down by quite a little bit.

It is normal for the pressure to fluctuate. It is a bypass/charging circuit system with an accumulator, meaning it will charge to a certain pressure,.. bleed off as the fuel is used,.. and re-charge when if reaches a minimum pressure that makes the pump kick back in and top it off again.

Thanks for the replay.I am concerned about this fluctuation because,when I bought the gauge a year ago and try it for first time I remember the arrow on the gauge was steady,no any move 160 psi at idle.Now is shaking +/-50 at idle and up to 150/200 at hi rpm.Do not looks normal for me.