Fuel Pump? Or is it me?

[Prsnumbaone]

Alright I was driving to work and car began to sputter a little bit...Then Bam! Cylinder 2 Misfire. I had figure it might be the itv22 spark plugs i had change about 1000 miles ago. So i went ahead and took them out and put the stock plus back in. Turn the car on drive it and partial throttle and i notice my fuel pressure dip insanely into the 600 at around 4500 rpms. Let off and car jumps back up to 1300 while im driving. then BAM! cylinder 1 misfire. So im thinking its the fuel pump now. Luckly i had an extra fuel pump from an older motor. I change the fuel pump turn the car on and i have get over 80 psi at idle ^.- ...(attn) So i decide to try and put the old one back on that was running around 400 psi at idle.. and as soon as i install that one and get the car running it sits at 70 psi...Can anyone tell me what the hell is going on, cause i am beyond lost. Could both pumps be completely shot?

 

[bova80]

could be your relief valve

 

[Prsnumbaone]

I could check that but would that explain while the old fuel pump was holding 400 at idle and now its only pushing ~65 psi :/ when I reinstalled it

 

[bova80]

or it could be the solenoid on top of the valve

 

[Prsnumbaone]

yea possibly... any idea where i could find one for sale?..it just wierd that now the one that was holding pressure at idle wont even go past 100 psi...it wouldnt have to do with the lines not pressuring right would it?

 

[Kiseliok]

Any pressure related issue I've had were all pump related... Mostly because I kept switching pumps and internals back and forth.
I doubt your lines have anything to do with this.
Pressure release valve Could be an issue, but I haven't heard that one go south before. It's a relatively straight forward piece... been f*ckin with it for a bit. haha
Solenoid is a possibility also, but I'd definitely look into the pump first. Got another pump you can borrow from someone, maybe?

 

[m4tic]

intank only pressure means the solenoid on top of the cdfp is not stepping up fuel pressure; check the wire harness and relays... Your original problem sounds like the relief valve became unseated (needs to be replaced)

My RV went bad from raising commanded DI pressure in low load areas