~Cadillac Deville Concours 59,000 A DISASTER??~

[submariner409]

Yeah, I ran that through my FPR search and figured that, if the lower O-ring was squashed instead of the tip seated in it, she wouldn't have been able to push the FPR far enough down to install the hairpin retainer.

(Got your PM. WILCO.)

[Cadillac_Cutie]

~It WAS very hard to get the FPR to go down inside the "WELL" far enough to attach the pin. Took a couple trys and some pushing down. I thought maybe it was because the NEW piece was taller than the OLD piece. Now Im thinking I SQUASHED the little black piece instead of it going onto the tip like it should be. No gas leaking around it but Im still concerned...so this morning I will remove it...fish out the black rubber ring and install it again hopefully the RIGHT way this time. Better safe than sorry. Yea she does seem to be driving a bit different. Nothing major or anything anybody driving her for the first time would notice. But she did drive real smooth before and now she feels sorta "bogged down" or not as much power? Make any sense?~

~Well I will re-do it this morning and see how it does the rest of the day! Let u guys know....and no I dont have a steth but I will definatly get one haha sounds interesting. I live right on a busy highway. I can imagine the looks I will get when Im "LISTENING" to my motor haha. "Wow look at that dumb female trying to diagnose her car like a DR". I already get major looks when Ive got the hood popped and my hands underneath. Im like a pedophile in a playgound...touchy feely with my motor haha!~

[submariner409]

Nice to correspond with a car wrencher who has a good attitude.........my .02

[Ranger]

Cutie, I think you are on the right track. Remember, that plunger on the bottom of the FPR is supposed to seal when it is fully extended. Keep that in mind as you look at it and put that O ring on it. When vacuum is applied, it pulls the plunger up off the seat. If you envision that, it will help you understand it and get it installed correctly. Good luck and keep us updated.

[Cadillac_Cutie]

~Sorry I havent replied yet I havent gotten around to fixing the problem until this morning.~

~Okay so I took off the FPR and fished out the little tiny O ring and put it on the FPR. I put the FPR back into place and the PIN went on alittle easier this time so Im pretty confident I didnt have the O ring seated right before because it was much harder to get the clip on before.~

~Started right up no leaks no problems but I havent driven her yet. Im still a bit clueless as to what you mean by its susposed to seal when fully extended. I slide the O ring on the tip just like in this picture. Was I susposed to leave some space between it and the little screen looking thing?

See pic where I circled that is exactly how I have it. The tiny O ring is completely up against the little screen wheel looking thing. I left no gap or space then I put it back on the car.



ALSO what is the reddish/white striped thing on the picture pointed to in blue? Mine doesnt have that. Is that another ring or just a difference in parts?

[submariner409]

You have it in correctly. The flat ring thing was a nylon or teflon guide ring that is not installed on my spare replacement FPR either.

[Ranger]

Im still a bit clueless as to what you mean by its susposed to seal when fully extended.

The FPR is a spring loaded pressure relief valve. If you pushed on the plunger where you put the O ring it would have retracted. It forms a seal when extended. Let me try to put this in simple terms. The fuel pump puts out 45-50 psi fuel pressure, too much at idle, so some of that fuel needs to get returned to the tank. The FPR opens and closes based on manifold vacuum (WOT = low vacuum. Idle = high vacuum). It keeps the fuel pressure constant across the injectors so that you don't bog down when you go WOT (high fuel demand) from lack of fuel and returns the excess unneeded fuel to the tank at idle (low fuel demand). Does that make a little sense and help you understand what it does, how it does it and why it does what it does, or did I just confuse you more?

How'd I do Sub?

[submariner409]

That's how a Fuel Pressure regulator works.

But I'll throw a curve: These FPR's operate EXACTLY the same as an EGR valve in that there's an orifice in the bottom of the stationary brass tip. Inside the tip is a pintle (spring-loaded taper valve) driven by the diaphragm which is controlled by engine vacuum supplied to the infamous nipple that started this whole thread. SO, at high engine vacuum (idle, low rpm cruise), the FPR diaphragm lifts the pintle, lowering fuel pressure and volume by bypassing a significant portion through the round screen to the tank return line. As vacuum drops on power demand, the pintle closes at a calibrated spring/vacuum rate, raising both fuel pressure and delivery volume.

CC, it's all magic.........

[Tommy Deville]

CC, listen if its been working & you aren't smelling fuel than don't mess with it.

[Ranger]

Based on her last post I think she has it installed correctly now.