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**Safety Guy** · 01-26-2011, 10:19 AM

From what I'm reading, without manifold pressure, the fuel pressure regulator is at its most closed (but shouldn't be closed completely). Fuel should still flow through the rail. Perhaps at that point, when the valve is almost closed, there is gunk I need to clean out more thoroughly.

I might be taking the whole rail back out and into work to give it a thorough cleaning.

Karl

**resuwrecked** · 01-26-2011, 10:26 AM

im thinking check your fuel pressure. sounds like either a weak or dying pump. assuming fuel was the problem it would still run with max fuel pressure (regulator return somehow blocked completley)

please dont spend $58-$92 on a regulator

double check for constant b+ at the fuel pump when cranking

**Safety Guy** · 01-26-2011, 10:34 AM

Thanks. What's "b+"?

Should I look for a tee to splice into my fuel line up front to get a pressure reading?

Karl

**festivaWES** · 01-26-2011, 04:42 PM

Same thing iam battling with my b6t swap. No fuel from return rail out of pressure reg. I pulled the injectors and they are soaking in straight injector cleaner for 72 hours... Then, I plan on doing a DIY injector cleaning.

I called for a B6t fuel pressure regulator and they want 130 in my area! I'll get a billet rail and adjustable AEM reg before i buy from McAuto parts stores... Do the injectors pulse while cranking???

**crazyrog17** · 01-26-2011, 05:14 PM

I don't want to sound like an idiot but i've only got a few minutes (can't search this myself) and thought maybe it could help...?

I've read in some other parts of the forum that a simple mistake of hooking up the fuel lines backwards produces this issue.

Disregard this comment if it makes no sense, please.

**lessersivad** · 01-26-2011, 05:41 PM

Originally posted by Safety Guy View Post

Thanks. What's "b+"? Karl

I believe it's referring to constant 12 volts.

Which could have simply been typed as 12v.

Sure it would have taken up an extra space, but at least it would have been more clear.

**Safety Guy** · 01-27-2011, 11:40 AM

Here's what I did this morning:

Put another 2 gallons in the tank, since guage showed empty (I recall hearing gas swishing around in tank upon install, but who knows how low the pickup tube may go?

Tried to start Aqua: no go.

Undid fuel hose from top of fuel filter, put cup underneath, and cranked for about 1/4 second. Got almost an inch of gas in coffee cup (McDonald's medium size foam cup). Poured it into gas can before it could eat cup.

Seems to me that I was getting good gas. A co-worker had suggested last night that maybe there was a kink in the fuel line somewhere. I had to test that. I think this eliminates that possibility.

Next I removed both hoses from rail. Still no fuel present at the return line! FUEL IS NOT GETTING THROUGH RAIL TO RETURN HOSE CONNECTION.

Next I removed the fuel pressure regulator (FPR) from the rail. Used canned air to blow through rail. RAIL IS CLEAR. Both ways!

Tried blowing air through FPR. No go! Tried carb cleaner. No go! Currently it's sitting upside down on table with carb cleaner inside it to soak a bit.

QUESTION: Should air or liquid cleaner not go through the FPR when detached? It seems to me that it is indeed clogged. However, it may not work that way and be perfectly normal.

Does anyone know if the FPR should pass at least some gas or air from the fuel attachment pipe to the mount hole or vice versa? (Note: I'm not using the vac pipe part!)

I'm thinking this now: Either my FPR can be cleaned out or I need a new one.

What say ya'll?

Karl

**Pu241** · 01-27-2011, 12:03 PM

Karl, without the FPR on the fuel rail do you get fuel into the rail?

It is my understanding, though I'm not certain, that the FPR opens to return fuel to the tank when the pressure in the rail exceeds a prescribed limit.
Meaning it is closed till the pressure reaches the set point.
So I would expect no fluid (air or liquid) to pass through till the pressure exceeds some limit.

**Safety Guy** · 01-27-2011, 12:14 PM

Okay, John. Even though I seem to be getting good "flow" from my fuel line, it may not be building up enough pressure, right?

If the FPR does not let gas through until a certain pressure, then my "test" with it outside the car is useless.

I looked at the cutaway picture of the FPR in my manual to understand it. It doesn't say if the valve is completely closed at rest. It may be.

I'll be letting it soak overnight. Tomorrow I may then check it again to see if it "flows" either air or fluid. I can then reinstall it and then I see three choices:

1. Get a pressure gauge for my fuel line (either separate or install in car) to check FP.

2. Try a known good fuel pump (Twin's) to see if that starts the car.

3. Get that mobile car tech to come back and show me how to diagnose the problem (if he can). Cost: about $170! If it comes to that, it comes to that! I need Aqua running...yesterday!

Any other ideas?

Thanks John!

Karl

**lessersivad** · 01-27-2011, 12:19 PM

Note; I am by ant means an expert.
On the B3 the regulator opens more under higher vacuum conditions. I would think the B6 regulator would also.

I would try applying a bit of vacuum and see if any fuel/cleaner can make it's way thru from fuel inlet to outlet ports. If it don't then I would say you have a bad/plugged regulator. Plus if it does open it would allow the cleaner to get deeper into the ports to help desolve any crud that may be inside.

**resuwrecked** · 01-27-2011, 01:40 PM

Originally posted by lessersivad View Post

I believe it's referring to constant 12 volts.

Which could have simply been typed as 12v.

Sure it would have taken up an extra space, but at least it would have been more clear.

b+ refers to battery voltage, sorry to confuse you.

**Pu241** · 01-27-2011, 02:05 PM

Originally posted by lessersivad View Post

Note; I am by ant means an expert.
On the B3 the regulator opens more under higher vacuum conditions. I would think the B6 regulator would also.

I would try applying a bit of vacuum and see if any fuel/cleaner can make it's way thru from fuel inlet to outlet ports. If it don't then I would say you have a bad/plugged regulator. Plus if it does open it would allow the cleaner to get deeper into the ports to help desolve any crud that may be inside.

I do not believe the FPR is in anyway controlled by engine vacuum.
It is solely controlled by fuel pressure, which in turn is supplied by the fuel pump.
A spring inside the FPR is set to open at a pressure above a certain point, so that the correct amount of fuel is injected.
If the pressure in the fuel rail is too high, then when the injector opens, more fuel than necessary is injected causing rich running and poor MPG.

**lessersivad** · 01-27-2011, 06:25 PM

Originally posted by Pu241 View Post

I do not believe the FPR is in anyway controlled by engine vacuum.
It is solely controlled by fuel pressure, which in turn is supplied by the fuel pump.
A spring inside the FPR is set to open at a pressure above a certain point, so that the correct amount of fuel is injected.
If the pressure in the fuel rail is too high, then when the injector opens, more fuel than necessary is injected causing rich running and poor MPG.

Are you talking about the B6 specifically??

According to my Festiva shop manual, vacuum plays the part of controlling the amount of fuel in the rail that's available for the injectors. The high vacuum (deaccelerate) pulls the diaphram against the spring pressure which inturn opens the FPR return port keeping the fuel pressure at a preset level, and low vacuum closes the return port (accelerate) alowing the injectors to get enough fuel.

So the vacuum may not be all inclusive of the fuel pressure but it does play a roll into how much fuel is available.

**Pu241** · 01-27-2011, 06:29 PM

Then I'm wrong, and the B6 is different from the B3 FPR.

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