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



Cadillac_Cutie
04-28-08, 06:55 PM
~I just purchased my first Cadillac 3 weeks ago and its been a complete disaster ever since. Within the first week the car started failing to start on the first try....sometimes taking 2-3 trys to start up. Took her to the shop and they replaced the fuel relay switch. Was okay for about a week or so and then 2 days ago it started doing the same thing...hard to start...taking a couple times. Before I could take it back to have it rechecked for that I ran into yet another problem.~

~While sitting at the school waiting to pick up my kids I was running the AC as it was pretty humid outside. I only live 4-5 blocks from the school so once I picked up my girls I headed home. About half way home the car started to overheat. The Engine Coolant light came on, the check oil light came on, check engine light came on and the car started cutting out and being hard to steer. I pulled over to let the car cool off. It was in the 270's so I let it cool and tried to make it block by block home. I stoped 3 times to allow it to cool down but I finally made it home.~

~Popped the hood to find the (I believe) serpentine belt torn to shreds. Called the shop and they towed it in. I just picked the car up and was told my water pump belt was broke and they fixed it. Yet its still hard to start at times and the 0% oil life light is on still. Just a week ago the oil life said 80% so could the light be wrong? Also it's making this slow missing noise at idle.~

~What does it sound like is still wrong with my new Caddy? I was so excited to get my new baby but Im now ready to drop it off at the nearest doorstep haha! Im not great with cars and things like that and being a female the local shop tends to take advantage that I dont know what's going on with my car. Please if anybody can help me out with why such a low mileage car is having so many problems....Id greatly appreciate it!~

Ranger
04-28-08, 07:51 PM
Ok cutie, first tell us what year it is so we know if it is a 4.9 or a Northstar. Add that info to your profile so we don't have to ask and it will always be available. Wait a minute, did the Concourse have the Northstar? I forget. The Northstar has a separate water pump belt. If it broke you would loose cooling and thus overheat. The overheating is why you oil life went to zero. The oil was cooked. Get it changed immediately, if not sooner. i suspect you may have a 4.9 though, because the serpentine belt operates the P/S pump as well as the water pump, which would explain the hard steering. Now the question is, what caused the belt to go. Have the belt tensioner and idler pulleys checked. A bearing may have seized. Not sure what to say about the "missing noise".

As far as the starting goes. The fuel pump relay sounds like it was the problem. Not sure why it would fail again, but have them check the spade contacts where it plugs in for corrosion.

Let us know how you make out.

misfit6794
04-28-08, 09:12 PM
All years of the concours had the northstar, including 94-96. Chances are with that low of mileage it was your orginal belt, and there are probably alot of original parts on the car. Your starting problem sounds alot like a fuel pressure regulator, its about a 70 dollar part and 5-10 minutes of labor. Definetly have the oil changed as it has been cooked.

Ranger
04-28-08, 09:35 PM
OK, if it is a Northstar, you have 2 belts. The big serpentine belt on the front of the motor drives the P/S pump, alternator & A/C compressor. The water pump is driven by a small belt on the rear of the engine. Which belt went?

ejguillot
04-28-08, 10:08 PM
As to the idle miss, I would suggest a change of spark plug wires and spark plugs as well (you're in there already). The mileage on the car is low, but the wires (depending on the age of the car) are anywhere from 9 to 14 years old. If most of the 59,000 miles were city miles, those wires have a lot of hours on them.

Ranger, what do you think?

Also, if you have any mechanical ability at all I encourage you (if you're able) to learn to fix the Caddy yourself. You'll understand what's going on under the hood better, and as such are much less likely to be misled by a dishonest mechanic (for those jobs you can't handle).

Besides, there's a satisfaction in fixing it yourself! :)

Ranger
04-28-08, 10:35 PM
If cutie is talking about a misfire, then yes, could be plugs or more so wires. Could also be a vacuum leak or EGR pintle valve not closing completely.

Ranger
04-28-08, 10:44 PM
being a female the local shop tends to take advantage that I don't know what's going on with my car.
Check with us first. If nothing else, we can educate you a little or at least give you intelligent questions to ask. They may not be so quick to try to take advantage of you if they think you know what you're talking about.

Cadillac_Cutie
04-30-08, 11:05 AM
~Thanks for all the great comments. Sure helps when you know more about whats going on under the hood when you talk to the mechanic. Yes it does have the Northstar. Also the belt immediatly to the right side of the moter was the one that broke but Im confused now because you say the water pump belt is in the back? They told me they replaced the water pump belt. Im not too happy with the mechanic that did my car because he completely didnt even check the fuel relay switch like I asked him to and I wasnt aware that he didnt until I already picked my car up. Now I have to make another appointment and Im assuming will cost more because its another trip instead of while they are already under the hood.~

~I havent changed the oil yet....he didnt even check all the lights that were coming on because I just called him to ask him about the oil lights coming on and he said "I didnt even check that...just changed the water pump belt".~

~So I will go IMMEDIATLY and have the oil changed. It still isnt running 100% like it should. Nothing in particular just not as smooth as it was before. Since they replaced the fuel relay it worked fine for a few days starting up immediatly but then started back being hard to start shortly after that. There isnt any way the part they just put on has already gone bad is it? So I need to tell them to check the spades contacts for corrosion? Im going to check with another shop because this one doesnt seem to take me seriously when I tell them to check for certain things. Sounds like they just fixed what they needed to get it back running...but not running right. Maybe trying to ENSURE I will need to use them again real soon when something else goes wrong.~

Submariner409
04-30-08, 01:28 PM
If you have a Northstar V-8 the water pump belt is the small 3-rib belt under the guard at the top right (from the front of the car) of the engine area. The main drive belt is the 6-rib, long one wrapped around everything at the end of the engine on the passenger side. The water pump belt costs around $5 - $8, while the main belt is around $30 +.

What year is your car......? Look in your owner's manual for the correct grade of oil to use, and stick to that in a name brand oil. You won't need any additives or supplements so don't get talked into snake oil. Don't let the shop overfill the oil. The engine takes 7.5 quarts TOTAL with a filter change. 8 quarts is too much

There should be instructions in your manual on how to reset the oil life monitor.

Ranger
04-30-08, 04:57 PM
Also the belt immediatly to the right side of the moter was the one that broke but Im confused now because you say the water pump belt is in the back?
Cutie, remember the engine is a "sidewinder" (transverse mounted). The front of the engine faces the passengers side and the rear of the engine faces the drivers side. The "right side of the motor" would be up against the firewall. No belts there. Right and left is always as seen from the drivers seat, unless you are talking about the engine itself as I mentioned above. Do I have you totally confused yet?

Cadillac_Cutie
05-01-08, 02:46 PM
~Well I had the oil changed bright and early this morning. They told me they put in 7 quarts. Also they had to send out for the oil filter as they didnt have the type my car has on hand. Was there about an hour but finally they finished. They reset the oil indicator. I still have to take it back next week for them to try and figure out what's causing the car to not crank right up ont he first try sometimes. It doesnt do it all the time. Usually first thing in the morning and anytime the car has been sitting for over an hour. If you have started it within the last 30 minutes or so it cranks right up but other times takes a couple trys and you can smell gas when it does.~


~Not sure what kind of oil they put in it. They didnt tell me~

~Hmm I get you on the sidewinding moter thing. Took me a second but I got it. So the belt they replaced was on the BACK of the engine as it was on the RIGHT side if you are standing in front of my hood. They charged me $170.00 to do the belt....with labor. Seem's quite high now that I find out the part isnt all that expensive. GRRRR:nono:~

Submariner409
05-01-08, 03:39 PM
CC, I'm gonna ruin your day. The rate (labor) for replacing the water pump belt on a late Northstar is 0.4 hour and a dealer belt cost of $14.47, so at an $80 labor rate, that's $55 maximum.

Ranger
05-01-08, 05:29 PM
Yeah, I hope they kissed you to.

tateos
05-01-08, 05:32 PM
I think that your starting problem could be a leaking fuel injector

Dadillac
05-01-08, 06:39 PM
They charged me $170.00 to do the belt....with labor.
Did that include the tow to the shop also?

Don

misfit6794
05-01-08, 07:06 PM
I really think your starting problem is the fuel pressure regulator. There is a write up on how to check it and replace it in the tech tips section, with pictures.

Cadillac_Cutie
05-02-08, 10:03 AM
~Yes that included $45.00 towing fee. Can somebody send me the link on how to check the fuel pressure regulator? Yup I think next time I go to Mc Cartys Auto Repair Im going to ask them to take me on a date first before they pull out the vaseline :(~ Im definatly going to be getting to know my Caddy on more of a personal level so I can access things myself and who knows possibly fix it :) Thats the only way I will know Im not going to get screwed.~

~Thanks for all the great info and Im going to be asking quite a few more questions later on when I start inspecting my girl~

misfit6794
05-02-08, 04:08 PM
http://www.cadillacforums.com/forums/cadillac-tech-tips/61600-how-check-faulty-fpr-fuel-pressure.html

Ranger
05-03-08, 10:55 AM
Cutie, check the link misfit gave you. No need for a date or vaseline. You can do this yourself.

Tommy Deville
05-03-08, 12:21 PM
She still hasn't told us the year of the car.:hmm:

Cadillac_Cutie
05-04-08, 11:17 AM
Its a 1996....and Im posting on the link given. Havent figured out how to release the pressure and where in the heck is the NIPPLE?

Submariner409
05-04-08, 02:04 PM
The vacuum line, maybe plastic with rubber angle connectors, comes from the top of the throttlebody and runs about 8" back toward the fuel pressure regulator (remove the engine beauty cover). If you carefully twist and lift the connector on the little round thingy in the right rear of the fuel rail you'll see the vacuum connector nipple. That connector and the end of the hose you pulled off should (must) be dry.

Cadillac_Cutie
05-05-08, 06:24 PM
~Wow I just had a scary experience. Thought my Caddy was going to catch fire on me. I went out to run to the store and took extremely long to crank. The first try it didnt start but when I let off the ignition a loud POP came out from under the hood....and immediatly seen SMOKE coming out too. I popped the hood and under the "Beauty Cover" smoke was coming out. The Check Engine light also came on. She started right up after that....but now the Check Engine light is off. What in the hell happened just now? Does it still sound like the Fuel Pump Regulator? Smoke came from under the Beauty Cover but not exactly sure from where. Is it safe to check the FPR mid day like it is right now? I smell gas pretty strongly~:confused:

Cadillac_Cutie
05-05-08, 06:41 PM
http://item.slide.com/r/1/193/i/-pg3NZU55z8KfacbG5eO0XRPpq3YlwGV/


Shoot my camera batteries went dead before they saved the pics of my FPR but heres the one of the inside of the cover where you can see it burnt/singed the black cushioning inside it.

I will get pics tomorrow. Im a BLONDE so you will have to explain to me in BARNEY terms what youre talking about. I removed the little rubber hose coming out of the top of the FPR and there was alittle wetness of gas there inside the rubber hose. Also my FLR looks to be welded to a metal pipe there. How do you remove it if its welded together to the pipe? I will post pics tomorrow because my batteries are dead and its getting dark outside now.

fubar569
05-05-08, 09:36 PM
we are talking about releasing the pressure through the schrader valve on the fuel rail. it will have a cap on it. before you do this i suggest picking up a fuel pressure gauge with a push button to relieve the pressure. it should have a hose with it to drain the fuel into another container of your choosing. there shouldnt be alot, but it's worth having a catchcan for.

the FPR (fuel pressure regulator) should be held on to the rail by a clip. if you remove this clip, it will pop right out with little effort.
my 97 was this way and i doubt your 96 would be much different.

that pop could've been a backfire of some sort. fuel/oil puddling, reversion, ignition...BOOM...likely popped the pressure valve on the intake and the snapped it right back shut...

Cadillac_Cutie
05-06-08, 05:38 AM
~Could somebody give me a Carfax on my vin? 1g6kf5297tu297784
Service history etc so I can at least have an idea of whats been going on with my car. ALSO could the recalled fuel rail have anything to do with my problem? How do I find out if my car falls under this recall?~

Ranger
05-06-08, 10:06 AM
Cutie, Your description sounds like a leaky FPR. There should be no gas on the nipple or vacuum hose. Raw gas is leaking into the manifold. That is what you are smelling and what caused the backfire. Have it changed.

Cadillac_Cutie
05-10-08, 11:43 AM
~OK I think I made a boo boo on a very simple FPR test. I de-pressurized the thing that looks like where you air up your tire. Had a rag under it and used a screwdriver wrapped with another rag. An oz or so came out. Then I pulled the little rubber hose off the FPR and turned the key until the lights came on the dash but not to start it. I washed the little nipple thing and after a few seconds a SLOW drip started to form on the tip of it. So I guess my FPR is bad right? ~

~My problem started when I went to take the FPR off. I removed the clip but then all this gas started coming out from under it so I had to hurry and clip it back down. What did I do wrong? I de-pressurized it before doing all of this? Why is there gas coming out of it?~:thepan:

Cadillac_Cutie
05-10-08, 11:53 AM
~Heres a few pics...they arent very CLEAR but just to show what I did. Umm sorry I didnt get a pic of the gas squirting everywhere haha kind of was freaking out and trying to clip it back in place so that my car didnt CATCH on fire haha. My motor was pretty HOT so I was nervous thinking I was about to catch my Caddy on FIRE!~

You can see pics here

http://www.slide.com/r/vAX4NYTp4z-UEXlwFOUWllZzf77KIuzF?previous_view=mscd_embedded_ url&view=original

Cadillac_Cutie
05-10-08, 04:30 PM
~lol OK so I changed out the FPR. Quickest 5 minutes of my life. Wow I cant believe I paid $45.00 for the part and did it myself instead of spending $160.00 for the auto repair place to do it. So far its starting like a dream. Cold and hot starts. Only thing was the NEW FPR only had 1 rubber seal and was alittle different looking than the old one. I started her up and nothing was leaking...so I guess all it needs on the new one was the one seal. The old one had 2 rubber rings but so far this one is doin great. Will know tomorrow....trying to drive her around and then let her sit to see how it goes. ;) You guys are the greatest! Would NEVER have attempted to change it myself if I hadnt come to this group~

Submariner409
05-10-08, 05:09 PM
CC.....good on ya'. If you remember, did the new FPR have a groove for the second O-ring ? There should be 2 rings: 1 small one in the groove in the brass tip, and a larger one in the groove around the plastic body. The larger ring is a safety seal, sort a backup of the small one, to prevent gas from leaking onto the engine if the small ring fails (the fuel pressures run around 45 psi.

Hate to ask you to do the job over, but you might have to, salvaging the larger ring from your old unit. Gently roll it off using a wood toothpick or bobby pin to lift part of it out of the groove. When you put it all together use a smear of engine oil or household oil on both rings: things will slip together much easier.

Do it cold.......and if you're pretty sure there isn't a second groove in the new unit, don't sweat it.

Ranger
05-10-08, 08:31 PM
Maybe the O ring was left inside the fuel rail cup (for lack of a better word)?

The reason you had fuel squirting out after depressurizing it is because you turned the key on afterwards. That energizes the fuel pump and repressurizes the system.

Cadillac_Cutie
05-11-08, 12:30 AM
Well the old FPR had a rounded O ring and another ring but it was flatter and wider than the old ring...and alittle smaller in size. The new one came with the larger skinny O Ring but not the flat one...and the flat one wouldnt fit on the new one....Hmm should I take it off in the morning and check it out again? Will it be ok with just the one? The new part looked a bit different than the old....maybe it doesnt need 2 rings? The flat one wouldnt fit on the new part. Wonder what I should do. Let me know and I can take it off in the morning and recheck but I couldnt get it to fit today.

No pressure at all in the morning after sitting all night right? The DE-PRESSURIZING was the MESSY PART haha :(

fubar569
05-11-08, 10:09 AM
i've found my car acts much like a self-absorbed female some days...completely fussy, refusing to start, running like crap...etc........then i take it out on the highway and through the twisties and show it who's boss...then she loves me again...15-19mpg city and upto a new personal best of 33mpg highway...

speaking of the FPR...i need to check the one AJ had me install...been having a stupid hard time starting mine lately after sitting for awhile and having the same symptoms as cutie did...

doesnt help i'm also running slightly higher fuel pressure on a stock tune with stock injectors either...as soon as the master gets his 96-99 stuff perfected im sure we can work on this part too...

Submariner409
05-11-08, 10:10 AM
CC......Before you rip into the FPR again, take a pic of the old unit and post it. (You might also be able to see a pic of the new (upgraded ?) replacement in www.rockauto.com.)

CC, Call off the dogs!! I just looked at your FPR in RockAuto and it looks a bit different from the post-2000 units. You're good to go as-is. If it ain't broke, don't fix it !!!!!!! Jim

ejguillot
05-11-08, 10:10 AM
Good to see you're doing so well with your own repairs!

Remember the easy way to depressurize: Pull the fuel pump fuse or relay and start the engine. When the engine quits there will be very little pressure left in the fuel system.

Submariner409
05-11-08, 11:00 AM
CC........Take a look at RockAuto and see if your replacement unit looks like the two examples for your car....when I click on the pics I swear there are two O-rings.

hate to keep you jumping around, but as you know, pressurized gasoline is something to keep under control.......sorry for the bum post at 10:10 in #35.

Cadillac_Cutie
05-11-08, 10:05 PM
Ok so now Im worried. The little tiny rubble ring on the end was NOT on my new part. Only the larger O ring. Can I go back to the part store and tell them or what? Will they make me take the part off and swap for a whole new one? On the old part when I pulled the screen looking piece out I think maybe there was a tiny little rubber ring down inside the opening that I didnt get out. So if thats the case its down inside there but not sure if its on the little center thing or not or just pressed down in there against it??

Tell me what I need to do. The little tiny rubber piece is the one missing from my NEW part and thats the NEW one I have. The OLD part had a flat round rubber ring and a regular O ring but no little rubber piece. The flat ring wouldnt fit on the new part.

http://info.rockauto.com/SMP/PR207_FULL.jpg

Cadillac_Cutie
05-11-08, 10:11 PM
http://198.208.187.182/servlet/com.entigo.acdelcocatalog.servlet.ProcessImageServ let?languagecd=EN&countrycd=US&user=InternetUser&mfgname=null&prodlinecd=null&acpartnbr=12570622



Ok check the pic above. See the flatter ring? Thats and the other large O ring was on the OLD PART. The NEW part came with only the large O ring not the flat one and wouldnt even allow the flat one to fit on it. The SMALL O ring was not on either. It MAY been down inside where I took the FPR out of....I believe I did see a little black ring. Maybe I should take it all off tomorrow and fish out the little ring and install on the tip like it should go....OR would putting the FPR down inside there not slide it on the tip anyway??

Submariner409
05-11-08, 10:17 PM
CC....It appears, from your description, that the smaller O-ring remained in the FPR "socket" and the new unit slipped into place. That is entirely possible, given the shape of the FPR "snout". If the car runs satisfactorily with no fuel leaks, you're OK.

Put it this way: "You lucked out". Don't obsess...check the area a couple of times over the next week or so, and if all is dry and the car continues to run correctly, you're fine. (You can leave the beauty cover off until you're satisfied with your work. Good job.)

Cadillac_Cutie
05-11-08, 11:33 PM
~I drove it immediatly after replacing the part from KY to Indiana about an hour away and back with no problems. No starting problems anymore either so I know it fixed my original problem. What sucks is they replaced the fuel relay and charged me like $160.00 and it didnt even need it. They were GUESSING at what was wrong and I repeatly told them to check the FPR and they said "I DOUBT THATS IT". Im going to drive down to the shop tomorrow to let them know it WAS it and that me...a girl...natural BLONDE at that fixed it myself haha!~

~So I can leave the cover off this week without causing any problems until Im sure I have no leaks? Its not much work to take it off and on just a pain really considering if I need to check it often this week for leaks....to keep removing and replacing. So if the small O ring isnt seated in the right place I will have leaks from the nipple again or around the entire FPR? Just want to be sure of what Im looking for. Also if it does leak or become faulty while Im driving can this cause a fire hazard? Want to make sure what Im dealing with. I about had a heart attack when I had the gasoline shower after forgetting to re-depressurize it when I removed it lolol...if you can even imagine. Hot Motor+unexperienced :tisk:female+gas shower= 1 paranoid CHICK! :eek:~

fubar569
05-11-08, 11:55 PM
now wait till you start modding it...the addiction is very real and hard to shake!

Tommy Deville
05-12-08, 07:43 AM
Glad you got her runing to ur liking cutie.

Submariner409
05-12-08, 09:33 AM
Leave the cover off for a week: won't hurt a thing. Take a look once in a while. It would not leak from the vacuum nipple but around the side, where the big hairpin retainer clip goes around it. If you've driven the car a couple of hundred miles and all's well, you're good to go. Don't sweat it.

Do you have a stethoscope ??? If so, for your own entertainment, with the engine running at idle listen to the top of the valve/cam covers to get an idea of what the valvetrain sounds like. Sort of a busy clicking. Listen just next to the oil fill cap: timing/cam chain whirr. Listen to the top of a fuel injector at the metal fuel rail. Each tick is when the injector atomizes gas into the intake air stroke. (Keep hair and other stuff out of rotating machinery.........:rolleyes:)

Ranger
05-12-08, 11:21 AM
Sub, the one thing that concerns me is if the O ring was left down in the "well", for lack of a better word, maybe the FPR valve is not seating correctly. That said, I suppose if that where the case, fuel pressure would be low as fuel would be bleeding off into the tank return line and cause drivability problems. Agree?

Submariner409
05-12-08, 11:25 AM
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
05-13-08, 07:47 AM
~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
05-13-08, 08:20 AM
Nice to correspond with a car wrencher who has a good attitude.........my .02

Ranger
05-13-08, 11:14 AM
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
05-17-08, 08:37 AM
~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.
http://item.slide.com/r/1/11/i/-0fc8hK76D_hYgCAuWgw2ePfTBH1i8OT/


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
05-17-08, 08:56 AM
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
05-17-08, 11:35 AM
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
05-17-08, 12:37 PM
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.........:highfive:

Tommy Deville
05-17-08, 01:57 PM
CC, listen if its been working & you aren't smelling fuel than don't mess with it.
:tisk::thehand:

Ranger
05-17-08, 04:07 PM
Based on her last post I think she has it installed correctly now.