Inpa fuel pump test, pump noise coming from engine bay?

[E46 M3]

I'm trying to diagnose a dead check valve as I have to crank the car twice again ( Hella replaced 3 years ago)

For the life of me I cannot hear the pump priming on cold start / first start so I thought I would try to activate it manually via inpa so I can at least hear it.

However I'm not sure if this is the right test, when I activate it the pump sound is coming from the engine bay which makes no sense... to me it sounds more like the SMG pump?



Is my INPA messed up? I have a Aus spec M3 so no EKP for the pump.

[karter16]

I know what you mean - it's the same for me when I activate the fuel pump at full duty using MSS54 DS2 Tool. I thought that the noisy bit was the fuel return valve which is a lot further forward than the pump. I'm confident the sound in my case isn't the SMG pump, they're not the same sound.

Also I'm pretty certain the SMG tests are via DS2 direct to the SMG control unit not the DME, so wouldn't be possible for one to trigger the other anyway.

[jos440]

If the pump activation in INPA is making noise from the engine bay, I’d also suspect it may not be the fuel pump test you’re actually triggering. On the E46 M3, the SMG hydraulic pump can definitely be heard from the front/engine bay area and can be confused with other components.

The fuel pump should be audible from the rear of the car (near the right rear seat/fuel tank area) when it primes. A quick test would be to remove the rear seat cushion and listen directly above the pump access cover while commanding the pump on.

Also, don’t rely only on hearing the prime check actual fuel pressure after the car sits overnight. A leaking check valve, injector leak-down, or pressure regulator issue can all cause extended cranking even if the pump itself is working. A gauge on the rail will tell you if pressure is bleeding off.

Since the Hella pump was replaced 3 years ago, I’d verify the basics before replacing parts again.