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New 040 Fuelpump = 120psi Fuel Pressure = Bad!

CEF11E

By CEF11E,
in Engines & Forced Induction

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CEF11E Veteran

CEF11E

Posted
Posted

OK.

I have just fitted an 040 to my car and powered it vai direct feed from the battery using a relay to trigger the pump to turn on.

The pump is in and working, providing fuel pressure and starting the car. The problem is the pressure. I have a fuel pressure guage that mesures fuel pressure right after the fuel filter. (the silver round thing in the picture at the top left on the line marked fuel supply) My standard pump was providing 38psi. the new bosch 040 is providing well over 100psi!!!!!

OK so that is probably normal right?

I am really worried that the enging is seeing 100psi fuel pressure. I started the car and black unburnt fuel is coming out the exhaust.

engine.jpg

If you look the engine photo you will see that the fuel pressure regulator is in the RETURN line going AWAY from the engine. The fuel supply line does not look like it goes to the reg at all. it goes under it somewhere and I think strairgt to the fuel rails.

so it goes fuel supply>fuel rail>injectors>fuel pressure regulator>return to tank.

I am really confused and need help.

are my injectors getting 100psi fo pressure? They are hose and tail injectors and I don't want to even start the car with that kind of pressure.

CEF11E Veteran

CEF11E

Posted
  • Author
Posted
should be fine, as the excess fuel is directed back to the tank.

if your really that worried, get a quick dyno readout done to check your afrs

I just drove the car and it is running so rich it will not accellerate under boost at all and clouds of black smoke come uot the exhaust. :P

looks like the reg can not cope. Can I put a reg inline just after the fuel filter? will that fix the problem?

CEF11E Veteran

CEF11E

Posted
  • Author
Posted

Ok, Bit of an update....

When you start the car it stays on 46pis for about 10 seconds and then WHAM~~~~~ in an instant the guage goes to well over 100 psi (off the reading)

so I am thinking the reg can't hold the pressure of the pump and it shits itself.

So I guess I need a new pressure regulator.

Can anyone tell me where the hell I can get on in canberra today?

Cheers!!

BHDave Grand Master

BHDave

Posted
Posted

The first thing i'd do is check that the return line to the tank isn't blocked. If it isn't move on to step 2

To get that sort of pressure (without a blocked return line) your reg would have to be stuck shut. I have an 044, stock reg and have base pressures below 40psi.

Don't get a reg before checking the return line! Oh yeah, you fuel hose probably wont be too happy with you either at those sort of pressures, partiularly if you haven't replaced it recently.

CEF11E Veteran

CEF11E

Posted
  • Author
Posted
The first thing i'd do is check that the return line to the tank isn't blocked. If it isn't move on to step 2

To get that sort of pressure (without a blocked return line) your reg would have to be stuck shut. I have an 044, stock reg and have base pressures below 40psi.

Don't get a reg before checking the return line! Oh yeah, you fuel hose probably wont be too happy with you either at those sort of pressures, partiularly if you haven't replaced it recently.

Thanks BHdave, you were on the money with one thing.

I put the return line in a bucket and started the car. It flowed perfectly for 5 seconds and then nothing. the stopping of flow happend at exactly the same time as the guage went from 50psi to well over 100.

So the reg is just locking shut about 5 seconds after the engine is started.

'd be a bit careful with that sort of high extreme pressure

if one of the lines fails, shit will go bang big time with fuel going everywhere.

off topic, what engine ?

Yep there is no way I am even starting it again till I have replaced the reg. paulr33. The engine is a VG20DET with RB25 hiflowed turbo and methanol injection... and now a bloody rooted fuel reg :D

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
should be fine, as the excess fuel is directed back to the tank.

if your really that worried, get a quick dyno readout done to check your afrs

You've got to be kidding :D

Anyway, what BHdave said, he beat me to it :)

Pressure RISE is due to the reg, or something after it.

Poor pressure before the reg

CEF11E Veteran

CEF11E

Posted
  • Author
Posted (edited)

thanks R31Nismod...

I laugh every time I see your avatar :D

I am thinking one of these sard regs will do the trick. I am not going to buy a malpassi as I have been told they are shit... Do these look genuine? seems like a really cheap price.SARD FPR

Edited by CEF11E
R31Nismoid Grand Master

R31Nismoid

Posted
Posted

:D it is most amusing. Although it was put there by a certain admin and is most amusing, i think im a victim.

Whats wrong with using another stock reg?

RB25 stock regs are perfect for huge power

Im no VG expert, but i dare say its probably a very similar (if not the same) reg.

CEF11E Veteran

CEF11E

Posted
  • Author
Posted

I am afraid if i get another stock reg it will do the same thing. Also the reg I have at the moment is twin entry so an rb25 one will need to be teed into.

I have already ordered one of the sard ones for $130. if it sucks I will cut it up into little pieces and set fire to it...

dangerous_daveo Grand Master

dangerous_daveo

Posted
Posted
I am afraid if i get another stock reg it will do the same thing. Also the reg I have at the moment is twin entry so an rb25 one will need to be teed into.

I have already ordered one of the sard ones for $130. if it sucks I will cut it up into little pieces and set fire to it...

LoL if it sucks man, your car might set it on fire for you :)

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