Is a failing fuel pump the only cause of low fuel pressure?

[AutoEuphoria]

I've been having some issues lately with my car...I've posted in other sections, but I'd like to post this log here to help ask a related question:

Notice the fuel pressure is ridiculously low. I have been babying the car since that datalog waiting for the big monthly bills to get out of the way so I can order another set of fuel pump internals. However, I am just curious if anything else would cause low fuel pressure other than a failing fuel pump? I noticed today that when I got in my car at lunch (cold engine) I saw fuel pressure of <100psi at one point just accelerating lightly up to the speed limit. However, later (after engine was warm) I was seeing fuel pressures of 1600+psi. So, I'm just confused.

My main question, I suppose, is if the MAP sensor or Boost control solenoid would cause low fuel pressure if either were acting up? I didn't notice this kind of low fuel pressure until after I removed the MAP clamp (which tapped into the MAP sensor wire) and manual boost controller (which bypassed the BCS).

Thank you for any help/input/suggestions/etc. (drinks)

 

[bykeryder4life]

if the pressures are dropping like that- dips below 100psi especially your pump is failing. It's got nothing to do with your map clamp and boost controller.

 

[matsuda]

You can disconnect (electrically) the boost control solenoid.
The engine should run fine (with a lower max. boost pressure).

In your graph, when the fuel pressure drops, the WG duty eventually drops to zero. This means that the ECU is trying to keep the boost pressure relatively low.

Do you notice any stumbling or hesitation when the engine is cold?

 

[AutoEuphoria]

Driving normally, no. I don't dare push it even a little bit at this point (when the engine is cold) to try. I will try disconnecting the BCS and see if that changes anything...that is great advice, thank you!

I suspect it IS the fuel pump, but if by some chance it's the cheaper solenoid, that will be very welcome news indeed.

 

[AutoEuphoria]

A bit of an update - disconnected the BCS and still had the same problem, so it has to be the fuel pump. Oh well...stupid expensive hobby

 

[bykeryder4life]

no offense but,.....told you so. Think of it like this, you went out unplugging the boost control solenoid to check this s***- it doesnt do anything for your fuel PRESSURE, volume yes becuase there is lower max boost pressure as Matsuda stated so there wont be the same volume, but if the pressure drops especially like you stated its the fuel pump not keeping up and eventually failing. You need new internals.

 

[AutoEuphoria]

Yup, exactly right. Just hoping it might be that $60 part instead of the $260 part, but oh well. Thank you for all of your help...to everyone who helped me figure out what was going on.

 

[bykeryder4life]

what kind of internals are you running right now?

 

[AutoEuphoria]

I was running the set of upgraded internals that PG was selling when they first came out. I installed via the how-to writeup BEFORE it was revealed to not use gasoline to lube/clean the parts. I'm guessing that led to a premature failure of the part.

 

[essejkcamraw]

I was running the set of upgraded internals that PG was selling when they first came out. I installed via the how-to writeup BEFORE it was revealed to not use gasoline to lube/clean the parts. I'm guessing that led to a premature failure of the part.

if they were the FIRST set that PG was selling that would make them the carpe diems im assuming no? if so thats why they are failing. but theres even a few people with failed KMD internals also. as far as i know. PTPs pumps have worked really well for a lot of people.. maybe look into that.