Z4 has an in-tank filter and pressure regulator combo (p/n 16117168284). Working the Z4 tank is a PITA - you have to drop exhaust and shields, empty the fuel tanks (best as you can) and bottom-side mount (so be ready to catch fuel, even if you empty). IMHO I'd replace the in-tank filter while you are there.So just to clarify, it is not necessary to run an inline filter with the z4 pump setup. Lol please pardon me, I do alot alone and I'm trying to map it all out
So why is a check valve needed for the LPFP sensor? In fact it leads me to wonder what the in-pump check valve is actually for? My recollection is the LPFP fires up the moment the door is actuated.If you have no sensor then you won't need a check valve, but if you do just piggy back it of the filter
So why is a check valve needed for the LPFP sensor? In fact it leads me to wonder what the in-pump check valve is actually for? My recollection is the LPFP fires up the moment the door is actuated.
Got it. Makes sense.If you have a lpfp sensor and it doesn't see pressure or very low pressure it could throw a code (speculating and not tested)
LPFP kicks on at least at LK15. So isn't there full pressure all the time at start?Also having pressure at start up will make starting the car easier.
Honestly not a question of money - that's an arbitrary assumption. I was trying to understand the purpose of the check valve anywhere in the system prior to the HPFP (currently in the LPFP, internally). I don't understand its function given the LPFP is turned on and pressurizes the line prior to engine start. Studying the 525/535 spec sheets, it seems that in-pump check valve really has a significant impact on flow. Assuming they are basically the same pump, but one without the check valve.For a few dollars there is no reason not to run one.