shroeder valve replacement

[furyus65]

I just bought the fuel pressure regulator or shroeder valve and woudl like to know if there is anything I need to be careful of while doing it. like seals or certain ways to install or remove. I could use a refresher course on reducing fuel pressure and I know I need to disconnect the battery before I even start on it.

I'll try it on Saturday so any help between now and then would be appreciated.

thanks,

Jason

[azkkn]

i usually put a rag around the valve and use the tip of a phillips screw driver to relieve the pressure. then just pop out the valve using a core removal tool and continue with the instalation of your parts.

[Injuneer]

Re: shroeder valve replacement

Originally posted by furyus65
I just bought the fuel pressure regulator or shroeder valve and woudl like to know if there is anything I need to be careful of while doing it. like seals or certain ways to install or remove. I could use a refresher course on reducing fuel pressure and I know I need to disconnect the battery before I even start on it.


Jason

The fuel pressure regulator (FPR), and the Schrader valve are two different things. You can change the FPR, you can't change the Schrader valve unless you buy a new fuel hard line.

If you are changing the fuel pressure regulator, relieve the fuel pressure as noted above. I generally don't disconnect the battery when doing something that doesn't involve any electrical wiring. Remove the vacuum compensation hose from the FPR. Then release the clamp that holds the two hard lines to the intake manifold. There is no need to relase the plastic lines from the hard lines.

Then remove the C-clip that holds the return hard line to the FPR and pull the line out of the FPR. Remove the single screw (T-27) that hold the FPR to the back of the intake. Twist the FPR gently and pull outward from the rail. The hard line and the FPR will have O-rings on them. Make sure the new AFPR has the O-ring on it, and simply reverse the above procedure.

[Rob B (shoebox)]

As always, it never hurts to have a visual reference (if it is a 94-97 rail). Screw #11 that holds the regulator on is a T-30 torx, #17 is a T-25.

[furyus65]

thanks guys for the information I'll let you know if I have run into any problems.

Jason

[Flash 97 WS/6]

As long as you don't have a strut tower brace, you might find it easier to just pull the whole fuel rail out to work on this... I hate trying to work back in that area where you can't see.

I just replaced my FP regulator on mine about 3 months ago, I painted the intake and polished my fuel rails while I was at it .

[furyus65]

fp regulator vs shroeder valve

saying that these two things are different got me to thinking.

1) no one recommended the fuel pressure regulator and I seem to have good fuel pressure since the car seems to run fine. Am I wasting my time putting this part on? Could this be the culprit because it smells like gas under the hood?

2) since I have 150,000 miles on it does the fuel pressure regulator have a shelf life or replacement time? I ask this because the part is $70.00 and I could put that money towards other repairs on the old girl.

3) should I do both the shroeder valve and the regulator? If so how hard is it to remove the metal fuel line? I think it may be time to break down and by a T/A repair/service manual and toss my chilton's book.

I have the next few days off to do the repair so a quick response this weekend would of course be appreciated. Then again, that is a redundant request becasue you guys are always quick to help.

thanks again,

Jason

[Injuneer]

Re: fp regulator vs shroeder valve

Is there a specific problem you are trying to solve? Is it concern over a fuel odor? Have you checked all the lines, the fuel pressure regulator, the core of the Schrader valve, and the vacuum line from the intake manifold to the fuel pressure regulator.

I wouldn't just start randomly replacing parts in the hope you find and cure the problem... that's what most of the dealers do.

As far as the Schrader valve.... it is a metal fitting swedged to the hard fuel line. It can leak at the base where it connects to the fuel line. It is not "replaceable"... although I have seen people replace it with a couple lengths of rubber hose and some clamps... not a great idea, but possible. But again, its not something that will generally "wear out", and it is not something that will just suddenly start leaking, as long as you haven't been trying to screw some sort of fitting or fuel pressure gauge onto it. The Schrader valve is just like the "tire valve" that you use to put air in your tires. It has a srping "core" that can be tightened with a valve core tool. It can also be removed and replaced with a valve core tool. But you need a specific replacement core, not a tire valve replacement core. Again, it is very easy to see if the core is leaking.... take the plastic cap off and feel for fuel.

Another possibility is a ruptured diaphragm in the fuel pressure regulator. This would show up as a problem with the fuel pressure. HAVE YOU CHECKED THE FUEL PRESSURE? If not, don't go replacing parts willy-nilly unitl you have made the proper checks. I leaking diaphragm will often show up as liquid fuel in the vacuum line that runs from the intake manifold (passenger side) to the nipple on the fuel pressure regulator. Pull that line off and look for liquid fuel in it, and smell it for signs of fuel having been in there.

If you have a fuel pressure problem, or fuel in the vacuum line, you replace the regulator. But not otherwise.

Where are you buying these GM parts? Are you aware there are sources that will sell them to you for about 1/2 of list price, plus shipping?

Also be sure to check the fuel lines that emerge from the fender, and connect to the clip on the side of the throttle body linkage cover. Then check the "quick connects" back at the rear of the intake manifold. There have been problems with the lines breaking away from the throttle linkage cover, falling on the exhaust manifold and starting fires. But leaks in these areas would be extremely visible.

As a general suggestion, the more you can post about the problem you are trying to solve, what you may already have done to try and solve it, etc, the more meaningful help we can give.

Fred

[furyus65]

thanks Fred

Fred, what a great post you gave. very enlightening and very helpful. No I have not checked the fuel pressure yet but I will go buy a fuel pressure tester tomorrow. My lines appear to be dry and not showing any leaks. However, the fuel pressure regulator nipple seems to have a blakened line from the nipple to the edge of the botton of the canister (like gravity would pull oil down a oil pan when a leak fromt the rear seal is noticed) So I just assumed that was the problem. (maybe I too can be a GM Good wrench mechanic with my replace all the parts until it stops mentality). I am so used to older cars and knowing what to look for with fuel leaks and such so I am undoubtedly coming off as an idiot when looking under the hood of my T/A right now.

Anyway, here is my plan for tomorrow.

1) check for fuel pressure (now just need to know how much pressure I should have)

2) check the rubber line from the fuel pressure regulator for wet fuel or a fuel smell. If there is one put in my fuel pressure regulator.

3) If it does not appear to be the fuel pressure regulator, check all fuel, and other rubber lines for leaks, breaks or burned marks and replace as necessary.

4) check the schroeder valve (tire valve type part for fuel while checking the fuel pressure)

If I find nothing wrong but I still smell gas it could be because I have put too much gas in at fill up and I may need to replace the ventilation canister or let the fumes vent themselves on their own.

Fred, the reason for my writing about this in the first place was because I smelled a strong odor of gas for over a week and could not use my heater or a/c because it would actually bring in more gas fumes. Since I did not see any obvious fuel leaks, I assumed that it was from me overfilling it as one fellow board member had stated it could be. The smell is not as strong as it was before and either I am getting so used to that I don't notice it or it is subsiding is still unknown. I saw a little mark of what could be called a carbon like drain line from the nipple of the FP regulator (which I thought to be the schroeder valve) and figured this was the culprit.

I called to the local auto store and it was 70.00 for this part so I called the dealer and the part was only a few cents cheaper than the local discount auto store and I bought my part directly from the dealer.

1) is there a cheaper price for this part that you guys are aware of?
2) is their a part that they make for better performance than the stock fp regulator and if so what is its cost? where do I get it?

again thanks for yoru help so far and I hope that I am not burdening you guys too much with thsi issue.

Jason

[Injuneer]

Hook up the fuel pressure gauge. Start the engine, and remove the vacuum line from the FPR (plug the line). Fuel pressure should be 43.5psi +/-2.5psi, so anything from 41-46psi is acceptable.

Attach the vacuum line. That will pull down the fuel pressure in proportion to intake manifold vacuum. Typical drop is 6-8psi, so you will see 35-38psi at idle.

Drive the car... the fuel pressure will vary with throttle position (or manifold absolute pressure). At wide open throttle (WOT) fuel pressure should return to the "no vacuum" measurement you got above. It should hold tha pressure to engine redline.

GM parts are available at about 1/2 dealer cost + shipping from:

Dal Slabaugh at Van DeVere Olds
lockitup@bright.net
800-362-9494

Jason Cromer at Sam Taylor Buick/Cadillac
staylorservice@cybertron.com
877-726-8295

There is no advantage in anything other than the stock FPR, unless you have a 1993.