Fuel pressure won't hold!! & Is is possible to ruin a new fuel pump?

[HeißeScheiße2]

1 - I've tested injectors - no leaks.

2 - I just replaced the fuel pump - as far as i know that thing is tip top (suspicious i may have killed it by running it when i had the return pinched)

3 - Maybe its the fuel pressure reg i need to get a new one.

4 - Is there anything else internally in the fuel feed system that would cause the loss in pressure? I have no external leaks

uh yes i'm a little worried. I was troubleshooting a fule pressure problem when i left the hose clamp on the return line and i ran the pump to build up pressure again. The pump made a weird "what the hell are you doing to me" noise. I wasn't able to hold fule pressure with the brand new pump installed anyway but i'm still suspicious that i may have killed it.

Anyway, i guess my real problem is my pressure. I still haven't installed a new pressure regulator and i hear that may fix the problem. My pressure holds and operates at 43-44 psi and then when i shut off the pump it drops after 5min and keeps dropping until it's at 15-20psi (if you leave it long enough). This was causing a vapor lock and consequently my car wouldn't start when engine was hot.

[promp3]

usually that is a fpr problem. there is a wierd set up that bmw uses it has somtype of bypass on it.(its a small box next to the tipicle looking fpr)
I have the compete set up I will sell to you for shipping+paypal fees if you want it, it worked fine on the car. but I am running an adjustable one.

[HeißeScheiße2]

usually that is a fpr problem. there is a wierd set up that bmw uses it has somtype of bypass on it.(its a small box next to the tipicle looking fpr)
I have the compete set up I will sell to you for shipping+paypal fees if you want it, it worked fine on the car. but I am running an adjustable one.

that's too bad i already ordered a FPR. Thanks though i might still need the 3/2 valve system. You're right that thing is weird.

[Steve530]

It sounds like a check valve problem. I assume that's what the 3/2 directional valve is. That would let the fuel return to the tank, so the pressure would fall.

[HeißeScheiße2]

It sounds like a check valve problem. I assume that's what the 3/2 directional valve is. That would let the fuel return to the tank, so the pressure would fall.

all good now pressure holds within bentley manual specs - 20min. however i still have my warm start issues and i'm getting a CEL with the codes Camshaft and Crankshaft fail . Funny thing is they're both brandnew!