[Crazyfurie]

i need some help, when ever i start my Cadillac, it has either 2 types of start ups.... at one, ill turn the key and it'll nearly instantly start up with 0 problems. and the second type is where ill turn the key, and it'll take like 2 seconds to start up, and when the engine finally starts going, it sounds as if its gonna shut off then it goes back to regular, this is while the key is still turned in the ignition.

it happens once in a blue moon, any ideas what this could be ? bad spark plugs perhaps?

 

[N*Caddy]

Re: what could this be a sign off? *weird start up*

Are those good startups mostly with the engine cold and the bad startups are mostly with the engine warm?
If so (but not only) go straight to the FPR (Fuel Pressure Regulator), disconnect that small vacuum line and watch if there is any moisture (i.e. gas) on the nipple. If so then you need a new FPR.

 

[maeng9981]

Re: what could this be a sign off? *weird start up*

Check your Fuel Pressure Regulator for proper operation. On a 99 Seville, pull the vacuum line off of the FPR while engine running. It should have no raw fuel around the nipple and/or vacuum hose.

 

[N*Caddy]

Re: what could this be a sign off? *weird start up*

Sorry for that maeng9981 I was just providing a service to the community

 

[maeng9981]

Re: what could this be a sign off? *weird start up*

Sorry for that maeng9981 I was just providing a service to the community

Oh no it's ok that is why I like this Cadillac forum; full of people with experiences and they are willing to help others.

 

[Crazyfurie]

Re: what could this be a sign off? *weird start up*

i have no idea where the FPR is, ill have to investigate it, or bring it to my mechanic to have him check it out. any idea how much this would cost me to replace if need be?

Btw thank you both of you for the help

 

[Submariner409]

Re: what could this be a sign off? *weird start up*

Remove the engine beauty cover. The Fuel Pressure Regulator is hairpinned into a socket on the rear fuel rail run. It has a vacuum line attached. You remove the vacuum line to see if there's any raw gas in the regulator or line - if so, the diaphragm in the regulator is ruptured and the engine is getting a much richer fuel mixture.

To replace it, you bleed off the fuel pressure using the Schrader valve (tire valve) under the black cap on the rear fuel rail. UN pin the regulator and pull it out - make sure the small lower O-ring comes out with the regulator. Oil the O-rings on the new unit, push it in and pin it. Connect the vacuum line. Turn the key:ON for 5 seconds, OFF for 10. Do it again. This primes the fuel system.

This picture may not be your exact FPR, but close............talk to Chris in RippyParts (Vendors ^^^) tomorrow morning.

 

[N*Caddy]

Re: what could this be a sign off? *weird start up*

Just remove the 4 black bolts holding the engine cover (the big silver plastic thing on top of the engine with "Northstar 32 Valve V8" written on it).
Underneath you will see this:

I put a red circle around the FPR and a yellow circle around the fuel pressure release valve.

It only takes 5 minutes and ANYBODY can do it:
1. Once the engine cover is removed disconnect the small vacuum line (just pull it out) from the FPR and look for signs of gas on the nipple. Should be BONE DRY. Any trace of gas is a tell-tale sign of a faulty FPR.
2. If you do find the FPR faulty then go to rockauto.com and select your year/make/model and browse to "fuel and air" find the FPR listed in there. Get the AcDelco one no other.
3. When you have the new FPR locate the fuel pressure release valve (see it circled with yellow) and unscrew the cap. It works just like a tire valve, press on the tip and the pressure is released. Be advised the fuel pressure is ~40PSI so have a rag to shield yourself and the engine until the pressure is dumped into the rad (about 2-3 seconds).
4. Now you are ready to remove the old FPR. Remove that clip and pull it out. Make sure all the rubber "O" rings are placed OK and then insert and lock the new FPR in place (a dab of oil on the "O" rings helps). Connect back the vacuum line and put the engine cover back.
Repair done.

P.S.
1) Any time you are opening the fuel line make sure the ignition is OFF.
2) Since yours is a 99, the fuel line is nylon, minor detail, all is the same.

 

[Crazyfurie]

Re: what could this be a sign off? *weird start up*

wow thank you!! prime tutorial

im def going to try this on a nice day *i live in upstate ny so its been raining and snowing here the past weeks * so ill wait till a nice day to do all this,

Thank you guys awesome help

 

[97northstardeville]

Re: what could this be a sign off? *weird start up*

In the upper left hand corner of photo, there is a vacuum line that runs to center far right photo. On the upper end of that line there is a PCV valve that must be cleaned with carb cleaner. If dirty that PCV will make enginerun rough and die.

 

[vincentm]

Thread is 2 yrs old bruh

 

[97northstardeville]

Re: what could this be a sign off? *weird start up*

Thread is 2 yrs old bruh

Yes, these achieved records are here to help anyone beyond those dates searching for solutions, isn't that the idea?

 

[JHowdy]

Re: what could this be a sign off? *weird start up*

Hi, here are two pics of my 1997 STS. I've been having difficulties starting the engine - once in a blue moon just as the other fellow said in the opening post - when the engine is warm and the car has been parked for half an hour or so. My STS seems to have nylon fuel lines (thick black lines), am I right?

I have marked the location of the FPR with a yellow circle. I checked the vacuum line: no visible moisture in the metallic nipple or in the rubber hose end. Bone dry. But when I wiped the end of the nipple with my finger and then sniffed it (the finger) there was a distinct odour of gasoline. So it seems to leak a little and should be replaced, right? Any comments are welcome.

 

[MoistCabbage]

And the thread is back from the dead again.

Yes, any sign of fuel at the nipple, including smell, indicates a leaking FPR.

 

[ewill3rd]

Re: what could this be a sign off? *weird start up*

Start the engine with the vacuum line disconnected. When the fuel rail is pressurized and the engine is running it will leak faster.

 

[JHowdy]

Re: what could this be a sign off? *weird start up*

Yes, nothing wrong with old threads! They are a great help.

Thanks, I'll order a new one right away. ^The other advice is most likely usable too, but I don't wanna ruin the vacuum diaphragm because I need the car every day .

Is there any difference in the quality between AC Delco FPR and say Standard FPR for example? I saw somebody commenting in some other FPR thread that you shouldn't use anything else than AC Delco in this case.

 

[N*Caddy]

Also replace the fuel line with the metal one. There is a recall on it and GM dealer should do it for free.
The thing is that if it lasted so far then will never have issues. The recall was because of a bad batch of lines from one of the suppliers and GM had no good batch control so is not clear what line went in what car thus the safest thing is to replace all. However not all lines are the bad one (yours for example).

Go always with AcDelco.
The parts are expensive in these cars but the labor is even more expensive so you save 10% on part but pay 2-3 times the labor...is basic math.

 

[Submariner409]

The Fuel Pressure Regulator for our cars is made by Robert Bosch in Germany and packaged by AC Delco service parts division.

Running rail pressure is listed as 41 - 47 psi.

You will not affect the regulator diaphragm if you run the engine with vacuum to the regulator disconnected.

 

[JHowdy]

N*Caddy, now you got me a bit confused. Do you mean that in principle the nylon fuel lines should be replaced by metal lines (because of the GM recall) but since mine haven't broken yet, there's no real need for it? I wouldn't touch them if I don't have to. I checked ebay and there were FPRs from different manufacturers (different brands) and the FPR itself seems to be different for the nylon and for the metal (steel) lines? I know if I contact a US car parts agent here in Finland they will most likely offer me something else than AC Delco and I wouldn't like to bother them with these stupid questions, because I'm not likely to buy from them anyway. Fair is fair...

 

[Ranger]

The FPR is a fairly simply device. It is one of those things that I would not hesitate to use an aftermarket part. Not 100% positive, but I thought the only difference between the nylon & SS rail FPR was the retaining clip.

The fuel rail recall was for the '95 - '97's. I think it was U.S. only. I'd pick up a stainless steel rail on Ebay and swap it out. You don't want to risk a fuel leak in the engine bay.