Fuel pressure when car is off...what should it be?

[czo79]

I'm trying to track down this weird problem I've had forever. My car doesn't want to start if it sits for more then 15 min. Sounds kinda like its flooded. I installed a fuel press. gauge after the fuel filter. After the car sits for a bit, it reads zero. I am under the impression that the system should have pressure in it even if the cars been off for a long time. Am I wrong? Anyways, my theory is that one or more of my injectors leaks, doesn't close, whatever when the car is off, bleeding of my fuel press. and flooding the engine, causing hard starting as the pump pressurizes the system and the flooded cylinder clears up. Can anyone tell me ab0out fuel press. when the cars off?
Much Thanks
Micum

PS: Does anyone know of any problems with putting a early (pre 95) wrx engine in a legacy turbo, with the wrx 440cc injectors and such, and running the stock legacy turbo engine managment?

[entirelyturbo]

Yes there should be some pressure after the car sits. The engine certainly needs it to start. It would be similar to starting a carbureted car with the throttle wide-open and the choke off.

That's why you have to relieve pressure by pulling the fuel pump wire and letting the engine use up the last bit of fuel before disconnecting any fuel lines.

I would assume the fuel pressure regulator is faulty. The FPR regulates fuel system pressure by sending extra fuel back into the tank, so it might be allowing all the fuel into the tank after the engine shuts off. The FPR is vacuum-operated so also check the vacuum hose that attaches to the intake manifold.

[vrg3]

Well, if you let your car sit overnight or so, there will be almost no fuel pressure. It's normal for it to eventually depressurize.

When you turn the key to the "ON" position, you should be able to hear the fuel pump power up for a few seconds. If you don't crank the engine, the pump stops. The idea is to repressurize the fuel rails.

[Legacy777]

FPR won't do what he's describing.

I think he's on track with his diagnosis of the fuel injectors leaking down.

What you could do is after an hour or so, pull all the plugs. Take a look at them, see if one is wet, and or see if you smell raw fuel from one of the plug holes.

See what you find and then go from there.

[czo79]

I was thinking about pulling my injectors and sending them to RCengineering to get them rebuilt/cleaned/blueprinted etc. I am hoping it might solve the problem...but thats a good idea legacy777 about checking the plugs, I'll give that a shot first. My question about rebuilding my injectors is, is there a seal/gasket/oring between the injectors and fuel rail that need to be replaced when replacing injectors? I'm worried about this, cause I got 94 wrx 440cc injectors, meaning (i assume) that I won't be able to find any seals or gaskets I might need to do this, cause these injectors never made it to the use.
Much thanks guys
Micum

[Legacy777]

Yeah there's some seals. I believe if you send the injectors off, they'll put new seals on them. I think is the key word. You'd want to ask them for sure.

However I think if you have a leaky injector, that may be something you just want to replace.

See what you find out with the plugs, and talk to RC and see what they recommend.

[czo79]

Josh, (its josh, right?)
You mean replace the injector as opposed to having it rebuilt? Thats going to be a little difficult and expensive, as I probably won't be able to find them in this country. I do have a contact in Tokyo who said he could get them. Expensive. Do you know if I could replace just one? Or should one replace them as a set? Perhaps replace one, and send all of them to be cleaned/rebuilt/ and most importantly, blue printed and flow checked/made equal, whatever you call it. Hey, I wanted to thank you man, you really do a lot to keep this a some other boards nice, running, friendly, helpful places to be. You're always there for everyone with a good idea...thanks a lot! Are you in on the never ending hood/bumper deal?
Micum

[ciper]

I got into the habit of turning the key on to ignition and waiting 5 real seconds before starting the car. This way the fuel pump has time to start. One of my older cars had the exact problem he describes. If I let the car sit for a few seconds it would start on the first click. Never took the time to figure out exactly why it happened.

My first guess would be a failing fuel pressure regulator

[Legacy777]

Micum,

I said replaced because I'm not sure if you can fix a leaking injector like that. RC would be able to give you a better idea.

I'd do the spark plug thing I mentioned and if you deduct one or more injectors are leaking down, call them and see what they recommend, and if they can fix it.

What makes your injectors so special? If you were to replace them, you should be able to find them in the aftermarket.

Thanks for the compliments, I do what I can

No I'm not in on the hood & bumper thing.

[czo79]

It just that the injectors are 94 wrx 440cc injectors. They use different ones on the US wrx and sti and legacy turbo. They never used the 440cc ones here and I think most people who upgrade probably go with sti 560's or whatever they are. I'm sure I will be able to get them eventually, it just might be hard and expensive.
Thanks
Micum