Knocking sound from the fuelrail?

i have an issue with random knocking sound from the fuelrail when the car is idling and it seems to be happinging when i rev as well. I can physically feel it in the rail, but no other place on the engine. FPR is mounted 5-10 cm lower on the firewall, but i cant really feel it there.

when the knock sound occur, i get a 10% ish rich spike afterwards, but i cant see any change in fuel pressure.

i do not have a non-return valve, so i tried just running the pump for a while before starting, which seemed to help a bit, but really har du say really.

i saw that my injector dead time was a bit out and have adjusted these now, but not been able to test afterwards.

im guessing this might be air related, but i've optimized the routing with no luck. i've also pulled the plug on each injector and the issue persist.

im also using a 044 pump and have heard that they might cavitate, and the sounds might resemble an hydraulic hammer.

im using emu black v3, 044 pump, and old unused aeromotive fpr that i have had laying around for 15? years.

any tips and pointers would be much appriciated

borrow a pump n reg off a mate n see? just to check.

Fit a Pulsation damper.

Have you considered that it might be one of the Injectors malfunctioning?

don't really have an easy way of borrowing an reg or pump. I do have a bosch 910, but i guess its ish the same as 044 wrt to pulsation.

my system is mostly an-pfte and hardline, so i guess there is an real potential for pulsation in the system. But my impression was that pulsation mainly came out as variation in the fuelpressure, not hard knocking. Though, there is probably air in the system and that will likely not help. I have not seen anything in the logs. What i see is a slow change, but i should check the sampling rate.

But yeah, i should get a pulsation damper. Any tips on any good ones? i see not allot of local motorsport shops carry them around here.

Tested the injectors by pulling one by one plug on the injectors, but the problem persisted, so that seems to not be the issue.

i've just gotten what i need to mount a backflow valve, so i will try that out + try to air out the system to see if that helps.

so after fixing a non-return valve and bleeding the system. No luck.

BUT….

i was sitting with the car on idle and i noticed i got spikes on hte acceleration enrichment.

Long story short. It was triggering async AE for seemingly no reason. I cannot se any reason to why it should trigger aAE. The log shows tps rate at 0 until aAE triggers. Then it goes to -21 somehow.

It helps to set async min tps rate up from 5 to 10, but anyone got any ideas here?