Is there a pressure spec for the fuel pump before the regulator?

What is the best spot to check this?

let's see... you have D-jet so the pressure before the regulator should be 32 psi and there is a post on the fuel rail that feeds the cold start valve on which you can clamp a pressure gauge to measure the fuel pressure.

before the regulator....like alot. it's just going to pour and pour and pour.

measure it from the center fitting on the fuel rail on the driver side of the engine....put a meter there....it's okay to disconnect the cold start valve, watch for gas though.

b

The spec for the fuel pressure, measured anywhere "downstream" of the fuel pump and "upstream" of the fuel pressure regulator, is 2 Bar. 1 Bar is about 14.5 PSI, so the spec pressure is 29 PSI. This should be the pressure the whole time the fuel pump is running; after the pump stops the pressure can and will drop.

Tap into the high-pressure loop of the system pretty much anywhere. The 2.0s have a separate single hose going to the cold-start valve, and that can be a convenient place to tap into. The 1.7s have a CSV that is "in line", so it's not as easy to tap into that. If there is an extra fitting on one of your fuel rails, you can remove the bolt in the fitting and hook up to that. Otherwise, you might need to build a "T" and put that in the middle of one of the fuel hoses.

--DD

When the ambient temp is over 70 and after the car has warmed-up the engine stalls. I've tapped into the cold start valve and when this happens there is no pressure on the fuel rail. Pump is still running though when I crank it over. After about 10-15 minutes it has pressure and will start up.

Is this common for a fuel pump failure?

Could it be something else such as a clogged in-tank filter? The inline filter is new.

thanks
dave

QUOTE (germaneighter @ Nov 8 2005, 01:47 PM)

Could it be something else such as a clogged in-tank filter? thanks dave

Yes, rust builds up and clogs the sock screen in the gas tank or a gooey crap from bad gas.

Can you blow compressed air back into the tank to clear the sock?

QUOTE (germaneighter @ Nov 8 2005, 02:01 PM)

Can you blow compressed air back into the tank to clear the sock?

No need. Once the tank is drained and you remove the line from the fitting, it just pulls out of the tank and can be cleaned or replaced. You'd have to drain the tank and pull the line to get the compressed air there, anyway, so you're already there.

The socks aren't attached all that well, and are frequently missing. Look down the gas filler hole into the round baffle, which is where both lines are. You can usually see the sock if it's still there. You can also see how much junk there is in the tank and decide if you need to pull the tank (another 10 minutes after you've drained the tank and disconnected the lines) and clean it.

Some have said a commonly available VW part can be used to replace the sock.

The other problem, btw, you may be facing is a blocked or pinched tank vent hose, which will allow the car to run for a bit, then it will die from fuel starvation as the pressure drops in the tank.

I fought a cold start problem for months.

I only traced it down once I teed in a pressure gauge that I could watch at all times.

It turns out that the check valve on the fuel pump would intermitantly stick, (sometimes fuel pressure sometimes not).

Your condition sounds similar. I think it's worth looking at.

Greenie

my engine would barely run (only bc it was carb'd) pinged like crazy no matter what i did. turned out to be a kinked fuel line.


b