Fuel pressure, Solved ! Options

[914itis]

My fuel pressure is set at 30lbs when the car is not running. When I start the car it read about 60 lbs. is that normal?

The car runs fine.

Djet 2.0 (IMG:style_emoticons/default/beer3.gif)

[euro911]

Paul, nominal psi for a standard T-4 FI system is 30. 60 psi is double what you need. What pump are you running?

[914itis]

I have a Bosch 2 port pump, I believe it is stock.

do you read it with engine running?

It is at 30 when i shut-off the engine.

[euro911]

See if you can get a part # off the pump. Is your pressure gauge accurate?

If your gauge IS accurate, the pump may be for a larger displacement engine.

[Cap'n Krusty]

The system runs at about 30 PSI. On shutoff, it usually drops 5-10 PSI and should hold that for at least 20 minutes. If it plunges to 0 on shutoff, there's a leak down problem, either with the pump check valve or the regulator (or, worst case, a fuel leak). Measure it running.

This should be in the garage forum.

The Cap'n

[914itis]

Thanks capt'n , I will try another gauge first. I tried to adjust the regulator and it only makes a difference when the engine is off . The gauge didnt move with the engine running as I turn adjust the regulator.
I think the fuel pressure regulator is the culprit. Are they generic? Can I get one from the FLAPS?


Admin please move this thread to the garage.

[914itis]

Admin please move to garage.

[Cap'n Krusty]

See if you can get a part # off the pump. Is your pressure gauge accurate?

If your gauge IS accurate, the pump may be for a larger displacement engine.

Engine displacement has NOTHING to do with fuel pressure.


The Cap'n

[euro911]

I don't know what '2-port' pump you have installed there, Paul, but it's possible that it's for another make of auto that requires a higher psi (for example, a 3.2L Acura requires 40 psi) (IMG:style_emoticons/default/confused24.gif)

Larger displacement engines require a higher volume of fuel during starting and heavy load, and some have pumps with up to 75 psi.

That's why I asked about the part # so we can see what you have there (IMG:style_emoticons/default/popcorn[1].gif)

[914itis]

I don't know what '2-port' pump you have installed there, Paul, but it's possible that it's for another make of auto that requires a higher psi (for example, a 3.2L Acura requires 40 psi) (IMG:style_emoticons/default/confused24.gif)

Larger displacement engines require a higher volume of fuel during starting and heavy load, and some have pumps with up to 75 psi.

That's why I asked about the part # so we can see what you have there (IMG:style_emoticons/default/popcorn[1].gif)

I will post the part number this afternoon. I don't think it's a wrong pump as it was fine for the past couple of months. I think that the fuel regulator may have went bad. I have a spare one that I will try to replace it after work.

[914itis]

Pump part # is 0580463010

I changed the regulator and it is the same result. Heading to the flaps nor for new fuel pressure gauge

[SLITS]

If you changed the regulator and the problem still exists, you have a pinched or plugged return line.

[914itis]

If you changed the regulator and the problem still exists, you have a pinched or plugged return line.

If a line is pinched or linked, shouldn't the pressure drop ?

[SLITS]

If you changed the regulator and the problem still exists, you have a pinched or plugged return line.

If a line is pinched or linked, shouldn't the pressure drop ?

The pump, "dead-headed" will put out far more than 30 psig.

If the suction line is pinched or plugged you will have little or no pressure at all.

If the return line is pinched or plugged you will see the total capability of the pumps' output pressure.

If you incorrectly hook up the pressure regulator, you will see the same problem ... high pressure in the fuel rails.

[914itis]

If you changed the regulator and the problem still exists, you have a pinched or plugged return line.

If a line is pinched or linked, shouldn't the pressure drop ?

The pump, "dead-headed" will put out far more than 30 psig.

If the suction line is pinched or plugged you will have little or no pressure at all.

If the return line is pinched or plugged you will see the total capability of the pumps' output pressure.

If you incorrectly hook up the pressure regulator, you will see the same problem ... high pressure in the fuel rails.

Great info , checking return line.......
Stand by............

[r_towle]

Stock pumps are 65 PSI out of the box.

Have you possibly flipped the feed and return lines around?
Did you replace the screen in the tank at the fitting? those do get pretty clogged.

The Fuel pressure should be at 30 running....much more than that and you are running way to rich.

The FI systems on these cars have no compensation so Fuel pressure is a key part of proper tuning..
The injectors just open and close.
There is no O2 sensor to give the system any feedback for running to rich...really just the CHT and once it hits a certain running temp its not even part of the equation anymore...

rich

[rudedude]

If the car runs fine "The car runs fine." why are you concerned?
Just curious?

[914itis]

If the car runs fine "The car runs fine." why are you concerned?
Just curious?

Well there has to be a reason why it must be at 30 psi. I was told that too much pressure can snap the fuel hose out of the rails even with the clamp.

[914itis]

You guys rock! You nailed it again (IMG:style_emoticons/default/poke.gif) . It was a kinked return under the tank. Thanks for all the help.