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No Fuel Pressure In The Lines When Engine Is Off

kosmo90

By kosmo90,
in General Maintenance

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kosmo90 Enthusiast

kosmo90

Posted
Posted

Hey guys, just changed my fuel filter and forgot to remove the fuse and crank the engine to relieve pressure.

Didn't matter anyway as there was only a tiny amount came out of the fuel hose when i removed it to get to the filter, last time i did it there was a fair bit of pressure there still.

Iv'e looked around and cant find why, i also don't have the "whoosh" sound when i open the fuel cap if that's any indication.

Walbro gss-342

555nismo injectors

New fuel filter :whistling:

I have deleted the carbon cannister, blocked off the hard line on the drivers side and removed the one on the passenger side (it just stopped near the cat with an open end anyway)

I dont know much about fuel pressure regulators or anything else attached to the system or how to check it.

Theres no leaks and no strong smell of fuel, has anybody got any ideas or tests i could do.

Search wasnt helpful at all, nothing came up for any fuel related queries.

Cheers

kosmo90 Enthusiast

kosmo90

Posted
  • Author
Posted

put your filter in backwards?

or didnt mix your lines to the reg around the wrong way by any chance...

not that I've ever made that mistake before :whistling:

HA that's the first thing i checked on google images, surely everybody cant be wrong :wacko:

MAD082, i was just reading about sealing the filler neck in the FAQ and i'll go and look for a new fuel cap, cheers.

Is the fuel regulator the one on the end of the injector rail? Got a feeling it is but whats the one attached to the body under the master cylinder?? another regulator??

The R33 manual is 3 books of not much help at all.

jiffo Mentor

jiffo

Posted
Posted

You have two different questions happening.

The lack of fuel pressure is probably your pump.

Rail pressure is maintained between the fuel reg and the pump, but to do this many aftermarket pumps need a non return valve fitted.

If the reg is working properly and so long as you can start without a few key on/offs don't worry about it. Pumps like an 044 are notoriously hard to start without a non return valve.

The whoosh at the filler cap is often caused from a poor seal job of the reduced neck when complying. But you've also removed the carbon cannister and its associated plumbing. I'd be more concerned that the tank can breathe as fuel is removed.

kosmo90 Enthusiast

kosmo90

Posted
  • Author
Posted

Thanks Jiffo, yes it does start on the first crank so maybe not a problem after all. I have resealed the filler neck and will replace the cap anyway though.

I might put the carbon canister back together then for breathing purposes, my only concern was the line that ran down the passenger side just stopped around the cat area with an open pipe.

I cant seem to find if it should be left open, i had a look around and cant find anywhere to connect it to.

Quick question: before it was imported, was there a carbon canister on there from the factory? I cant find much info at all on them.

Kinks Grand Master

Kinks

Posted
Posted

Pumps like an 044 are notoriously hard to start without a non return valve.

I wish I knew this when I was fitting my 040 in-tank!! Will have to source a check valve and pull it all apart again so it starts properly. For now I just try and remember to let it prime fully before starting but often I'm impatient and forget. Definitely annoying...

jiffo Mentor

jiffo

Posted
Posted

I wish I knew this when I was fitting my 040 in-tank!! Will have to source a check valve and pull it all apart again so it starts properly. For now I just try and remember to let it prime fully before starting but often I'm impatient and forget. Definitely annoying...

Do a couple of key on/offs to prime the system, it's the cheapest option.

The ecu times out the pump after about 5 seconds and often that's not enough time to fully prime.

The Bosch non-return valve is quite restricting, I'd suggest the tune will need a touch up if you fit the valve to a previously tuned fuel map.

post-73571-0-76202100-1364463951_thumb.jpg

Kinks Grand Master

Kinks

Posted
Posted

hadn't thought about it being a restriction. car still has a standard ECU so not an issue yet. old habits die hard I usually get in the car turn the key and it is running after half a second. having to wait for a daily's pump to prime is painful, and it sounds gay when I forget to wait and it won't start properly.

mad082 Grand Master

mad082

Posted
Posted

just change your routine slightly and that will make life easier for you. just start letting the pump prime before you put your seat belt on. my commodore daily developed an issue lately where it wouldn't start cleanly without priming first, so i just started doing what i said and it made life a little bit better.

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