Fuel Pressure Regulator

[DurocShark]

Found vacuum leak #2 today... The fuel pressure regulator.

From reading the Bentley, it appears that there's a single diaphragm that is operated under pressure by a spring and assisted by vacuum to drop pressure about an additional 7psi during high vacuum conditions (decel).

I yanked the vacuum line and plugged it. Now my part throttle stuttering is gone. (The idle was fixed by new points and the aux air regulator elbow.) I can live with losing a bit more fuel during decel for now.

Now here's my question: Does the fuel ever touch the diaphragm the vacuum is pulling on? Because if it is, then it would have to be leaking. But I cannot find any sign of leaks.

[spiffy]

Now here's my question: Does the fuel ever touch the diaphragm the vacuum is pulling on? Because if it is, then it would have to be leaking. But I cannot find any sign of leaks.

I am going to say that the fuel definitely touches the diaphram on the other side of the spring....it looks like it adjusts the pressure by changing the volume of the chamber on the front (front means front) of the regulator.
Let me know if you want the regulator and I will hook you up.

[DurocShark]

Now here's my question: Does the fuel ever touch the diaphragm the vacuum is pulling on? Because if it is, then it would have to be leaking. But I cannot find any sign of leaks.

I am going to say that the fuel definitely touches the diaphram on the other side of the spring....it looks like it adjusts the pressure by changing the volume of the chamber on the front (front means front) of the regulator.
Let me know if you want the regulator and I will hook you up.

Crap. I'm hitting the road for CO first thing in the morning. Grr...

[spiffy]

Now here's my question: Does the fuel ever touch the diaphragm the vacuum is pulling on? Because if it is, then it would have to be leaking. But I cannot find any sign of leaks.

I am going to say that the fuel definitely touches the diaphram on the other side of the spring....it looks like it adjusts the pressure by changing the volume of the chamber on the front (front means front) of the regulator.
Let me know if you want the regulator and I will hook you up.

Crap. I'm hitting the road for CO first thing in the morning. Grr...

I also referenced vwbusrepairman's fuel injection manual.....

Consolation...I drove my bus for a 2 years with the regulator hooked up to the throttle body (damn PO).....I am chasing a fuel delivery/hot head temp problem and I have a HUGE trip coming up in two weeks...I feel your pain

[DurocShark]

Now here's my question: Does the fuel ever touch the diaphragm the vacuum is pulling on? Because if it is, then it would have to be leaking. But I cannot find any sign of leaks.

I am going to say that the fuel definitely touches the diaphram on the other side of the spring....it looks like it adjusts the pressure by changing the volume of the chamber on the front (front means front) of the regulator.
Let me know if you want the regulator and I will hook you up.

Crap. I'm hitting the road for CO first thing in the morning. Grr...

I also referenced vwbusrepairman's fuel injection manual.....

Consolation...I drove my bus for a 2 years with the regulator hooked up to the throttle body (damn PO).....I am chasing a fuel delivery/hot head temp problem and I have a HUGE trip coming up in two weeks...I feel your pain

Well, I'll call around to find one but I don't have a choice on leaving in the morning. :( Sucks. No wonder I'm getting 13-15mpg.

[DurocShark]

Holy crap! $90 for a new one!!!!

(EDIT: $60 at Napa. The $90 price was from BD.)

[vdubyah73]

Napa is so cool they gots all kinds of stuff.

Bill

[spiffy]

Napa is so cool they gots all kinds of stuff.

Bill

Do they have GL4?

[vdubyah73]

Yes they do or so I've read on that other site. Search it on there and with patience You'll even be able to find the part number. It won't be that old maybe a couple weeks back.

Bill

[spiffy]

Yes they do or so I've read on that other site. Search it on there and with patience You'll even be able to find the part number. It won't be that old maybe a couple weeks back.

Bill

Sweet, thanks.

[Amskeptic]

Does the fuel ever touch the diaphragm the vacuum is pulling on? Because if it is, then it would have to be leaking.

If the pressure regulator is leaking on the vacuum side, it does not necessarily have to be a hole in the diaphragm where the fuel is indeed pushing against it. It could leak vacuum between the diaphragm and the crimp on the housing. I haven't seen one leak fuel or vacuum. I have seen the ball check lose its ability to hold back the fuel pressure when the engine is shut off and not throttle back the pressure under vacuum.
Colin

[DurocShark]

Does the fuel ever touch the diaphragm the vacuum is pulling on? Because if it is, then it would have to be leaking.

If the pressure regulator is leaking on the vacuum side, it does not necessarily have to be a hole in the diaphragm where the fuel is indeed pushing against it. It could leak vacuum between the diaphragm and the crimp on the housing. I haven't seen one leak fuel or vacuum. I have seen the ball check lose its ability to hold back the fuel pressure when the engine is shut off and not throttle back the pressure under vacuum.
Colin

Thanks.

I confirmed it's leaking vacuum, but cannot find any sign of fuel seepage at all. Even after driving home from CA. So it'll do as-is for now.

[VWBusrepairman]

I also referenced vwbusrepairman's fuel injection manual.....

1. It wouldn't be online without the help of Durocshark to host it
2. I served some jail time for the copyright enfringements for that stinkin' manual
3. glad it has been there to help you all
4. I am glad for numbered lists and fuel injection!

[DurocShark]

2. I served some jail time for the copyright enfringements for that stinkin' manual

Sooo... How's Bubba?

[spiffy]

2. I served some jail time for the copyright enfringements for that stinkin' manual

Sooo... How's Bubba?

Thanks to both of you....that manual is very handy.

What's that you say about the 'sisters'?