New pressure regulator in the fuel rail. 3.4 V6

No leaky injectors

Fuel pressure is 40 psi with engine running. Shut off engine & pressure drops to 0 is less than 30 seconds.

Isn't to stay at 40 psi with the engine off?

quote Originally posted by 30+mpg: New pressure regulator in the fuel rail. 3.4 V6 No leaky injectors Fuel pressure is 40 psi with engine running. Shut off engine & pressure drops to 0 is less than 30 seconds. Isn't to stay at 40 psi with the engine off?

It should hold pressure once the engine is off but will eventally bleed down. Maybe thte rergualtor is bad and causing the problem. I have a AFPR on the rail already for sale if you need one for your setup.

quote MstangsBware:It should hold pressure once the engine is off but will eventally bleed down. Maybe thte rergualtor is bad and causing the problem. I have a AFPR on the rail already for sale if you need one for your setup.

How long is eventually? 3 minutes, 30 minutes, 3 hours, 30 hours, 3 days or 30 days?

How can thte rergualtor (the regulator) be bad if I've just installed a new diaphragm kit in it?

quote Originally posted by 30+mpg: How long is eventually? 3 minutes, 30 minutes, 3 hours, 30 hours, 3 days or 30 days? How can thte rergualtor (the regulator) be bad if I've just installed a new diaphragm kit in it?

I would say it should hold pressure for at least 30 minutes. I have seen differant regulator hold for differant amounts of time. Maybe the diagram go installed wrong, pinched, is defective.

Actually the pressure loss is due to bleed back of fuel thru the pump back into the fuel tank.

Isn't there a check valve on the fuel pump? Isn't the fuel rail to hold pressure indefinitely?

If not, why do the repair books say to relieve pressure first when working on the fuel system?

Where's Whuffo when you need answers?

[This message has been edited by 30+mpg (edited 12-26-2008).]

I guess it could be a bad pump. It sounds more like the conector from the pump to the sending unit. If it can bleed down there, it will.

It sounds like it is in your tank either way. You never see any fuel due to it is just leaking right back into the tank.

That Todd Guy

Yeah, I've confirmed that it is not the regulator by disconnecting the return line from the fuel rail, get the pressure up to 40 psi and watch the needle on the gauge drop with the ignition off. No fuel comes out of the return hole where the line plugs into or drips from the injectors.

So tell me more about the fuel pump connection.

Do two tests: Jumper the ALDL terminal to bring pressure up with engine off, then pinch off the supply fuel line and watch pressure. Pressure should decrease very slowly or not at all. If it decreases quickly then the regulator is bad or an injector is leaking. Do the same test with the return line pinched off. If it drops quickly then either the check valve in the pump is bad or an injector is leaking. Also, disconnect the vacuum line to the regulator and check for the presence of fuel or fuel odor; if any, then the regulator diaphragm is perforated.

JazzMan

quote JazzMan:Do two tests: Jumper the ALDL terminal to bring pressure up with engine off, then pinch off the supply fuel line and watch pressure. Pressure should decrease very slowly or not at all. If it decreases quickly then the regulator is bad or an injector is leaking. Do the same test with the return line pinched off. If it drops quickly then either the check valve in the pump is bad or an injector is leaking. Also, disconnect the vacuum line to the regulator and check for the presence of fuel or fuel odor; if any, then the regulator diaphragm is perforated. JazzMan

The regulator is not bad, it has a brand new diaphragm kit installed as stated in my second post & the injectors don't leak. Please read my previous post.

[This message has been edited by 30+mpg (edited 12-26-2008).]

quote Originally posted by 30+mpg: The regulator is not bad, it has a brand new diaphragm kit installed as stated in my second post & the injectors don't leak. Please read my previous post.

Don't rule out that a new parts is not the problem--Myself and others can asure you that we have installed new parts that where bad. Or installed a new part and damaged it in the process making it into a bad part.

quote MstangsBware:Don't rule out that a new parts is not the problem--Myself and others can asure you that we have installed new parts that where bad. Or installed a new part and damaged it in the process making it into a bad part.

I fail to see how the regulator can be bad. You have failed to comprehend my previous posts. So here goes again:

1. The fuel rail has been removed from the manifold.
2. The injectors remain in the fuel rail.
3. The ONLY fuel line connected to the the fuel rail in the one from the pump.

4. The return line IS NOT CONNECTED.

5. Using the ignition, the fuel rail is pressurized to 40 psi.
6. With the ignition off, the pressure rapidly drops to zero.

7. No fuel is observed to drip from the injectors or EXIT the return port.

If the regulator is bad shouldn't one expect to see fuel coming out of the return port? Since it is NOT, the problem is clearly not the regulator.

I still think it is in the tank.
If you pull the sending unit (without messing with the pump or connector and submerge the bottom of the pump in fuel (preferably in something clear like one of those glass cake pans from the kitchen ) And cap off the supply line with a short piece of hose w/a bolt stuck in the end of it. (hose clamp the bolt in) Give the pump 12 volts and see if fuel shoots into the yard next door. Saftey glasses might be a good idea at the begining of this test. It shouldn't need power very long so be prepared to kill power very fast.

That Todd Guy

quote Originally posted by 30+mpg: The regulator is not bad, it has a brand new diaphragm kit installed as stated in my second post & the injectors don't leak. Please read my previous post.

Good luck with your hunt!

JazzMan

[This message has been edited by JazzMan (edited 12-26-2008).]

quote thefierofarm.com:I still think it is in the tank. If you pull the sending unit (without messing with the pump or connector and submerge the bottom of the pump in fuel (preferably in something clear like one of those glass cake pans from the kitchen ) And cap off the supply line with a short piece of hose w/a bolt stuck in the end of it. (hose clamp the bolt in) Give the pump 12 volts and see if fuel shoots into the yard next door. Saftey glasses might be a good idea at the begining of this test. It shouldn't need power very long so be prepared to kill power very fast. That Todd Guy

Each time the ignition is switched on, the relay provides electricity to the fuel pump for a couple of seconds. It takes 3 separate switchings of the ignition to get the fuel pressure up to 40 psi starting from zero. So the pump is providing the pressure, it just doesn't hold pressure after the ignition is switched off. (And NO the problem is NOT the regulator, for any who failed to read or comprehend my previous posts )

I totally get what JazzMan is saying. I can't tell you how many new parts I have installed have been bad. There is nothing more frusterating than finding out three days and many other parts that the first part you put on was bad.

with that said- I agree with the idea that with the fuel rail out and loose you would see fuel if it was leaking past the injectors or out the open return port if the reg was bad. Please do check the vacuum line for presence of fuel.

JazzMan- feel free to correct me if I am wrong.

That Todd Guy

quote thefierofarm.com:I totally get what JazzMan is saying. I can't tell you how many new parts I have installed have been bad. There is nothing more frusterating than finding out three days and many other parts that the first part you put on was bad. with that said- I agree with the idea that with the fuel rail out and loose you would see fuel if it was leaking past the injectors or out the open return port if the reg was bad. Please do check the vacuum line for presence of fuel. JazzMan- feel free to correct me if I am wrong. That Todd Guy

The vacuum line is not connected since the engine is not able to run with the fuel rail & injectors removed. No fuel from the vacuum port either. The only place left for the fuel to go is back up the line from the pump.