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Toymods » Tech & Conversions » Fuel pressure = 75PSI...on a stock 4AGE????What are my options for running new fuel lines???

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WHITCHY
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Location:
Castle Hill
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August 2003
Fuel pressure = 75PSI...on a stock 4AGE????What are my options for running new fuel lines??? Sat, 26 November 2005 11:22 Go to next message
Ever since I put the 4AGE in my Sprinter I have been getting about 200mks to a tank, no matter how I drive. and in the last 6mths it has developed a flat spot between 3500rpm and where TVIS opens at about 4300rpm.
I finally took it to a mechanic to get a fuel pressure test, and it came back as 75PSI constantly!
Can anyone suggest why the hell this is happening?
Mechanic said its most probably a blocked return fuel line, but when I changed the fuel pressure regulators on both ends of the fuel rail the flat spot disappeared for about 10mins then it came back again! Something is screwing out my fuel pressure regulators and its really annoying me!Can a fuel pressure regulator even get broken?don't they just operate via vaccum, so how can they break, let alone be broken within 10mins of installation?
I have a spare fuel rail with pressure regulators but I don't want to put it in just to fuk it out again within 10 mins and have to find another one!

Has anyone had a problem anything like this before?Can anyone help me out with fixing the dam thing so I can get my fuel consumption up to where it should be and more importantly get rid of that dam flat spot! I figure the flat spot is just the engine getting flooded with petrol, and then once TVIS opens it is able to use all that fuel and it picks up again. Sound right?

Thanks muchly to anyone that can help me out with this!
-Whitchy-

[Updated on: Mon, 05 December 2005 11:56]

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thechuckster
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February 2003
 
Re: Fuel pressure = 75PSI...on a stock 4AGE????Can anyone help me out with this? Sat, 26 November 2005 13:59 Go to previous messageGo to next message
is manifold vacuum reference (little pipe on teh regulator) connected to a port on the manifold?

sounds like it's seeing atmo pressure not manifold vacuum... or it's fucked.
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TA22-3SGTE
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MACKAY
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May 2002
Re: Fuel pressure = 75PSI...on a stock 4AGE????Can anyone help me out with this? Sat, 26 November 2005 23:40 Go to previous messageGo to next message
If the regulator fails the fuel pressure will go up but since you have tried another regulator it is probably as your mechanic said and you have a restriction in the return line , Try pulling the return line off the regulator and see if you can blow through it into the tank .

Trevor
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shinybluesteel
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melbourne
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June 2002
Re: Fuel pressure = 75PSI...on a stock 4AGE????Can anyone help me out with this? Sun, 27 November 2005 00:03 Go to previous messageGo to next message
easy way to check the return line, just run a 6mm line from the FPR to a jerry can/petrol tin away from your car and see if it makes any difference.

could try removing the dampener from the fuel feed fitting, i'm not running one and it doesnt seem to matter.
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oldcorollas
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Kita-Ku, Sapporo, Japan
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January 2003
 
Re: Fuel pressure = 75PSI...on a stock 4AGE????Can anyone help me out with this? Mon, 28 November 2005 02:17 Go to previous messageGo to next message
WHITCHY wrote on Sat, 26 November 2005 22:22

Mechanic said its most probably a blocked return fuel line, but when I changed the fuel pressure regulators on both ends of the fuel rail the flat spot disappeared for about 10mins then it came back again! Something is screwing out my fuel pressure regulators and its really annoying me!Can a fuel pressure regulator even get broken?don't they just operate via vaccum, so how can they break, let alone be broken within 10mins of installation?-Whitchy-


well, one end is a damper and the other end is a regulator... do they look different on your rail (stranger things have happened)

if the vac source was rooted, it would go to about 40psi + atm = 55psi ish...

75psi is far too high.

as suggested, try running return to a jerrycan and see what happens... it must be a blocked return if you have changed the reg and it still does it...

they can break... but would be more likely to fail open, giving no pressure?? maybe???

you could also try hooking up the rail inlet to the rail outlet (ie, with no reg) but with a gauge, and see what the pressure is when the pump is freely flowing back thru the return.. pressure should be minimal, but if not, it tells you that there is definitely a blockage...

good luck!
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Norbie
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Re: Fuel pressure = 75PSI...on a stock 4AGE????Can anyone help me out with this? Mon, 28 November 2005 03:48 Go to previous messageGo to next message
What fuel pump are you running? If it's a big aftermarket one it's quite possible it's pushing too much volume for the stock lines/regulator to handle.
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WHITCHY
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August 2003
Re: Fuel pressure = 75PSI...on a stock 4AGE????Can anyone help me out with this? Mon, 28 November 2005 04:07 Go to previous messageGo to next message
Ok, thanks heaps for the suggestions so far!
The fuel pump is just a stock AE82 4AGE pump that came from the same car the engine did.
Yeah the regulator and damper both look different. Is the one on the fuel in end the damper and the one on the return end the regulator?or is it the other way around?

Does anyone know where I can get a fuel pressure tester from?and roughly how much one would be? I just rang my local peps and they said no, its a specialty tool. So I take it I won't find one cheap? Anyone wanna lend me one?
Thanks again!
-Whitchy-
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Norbie
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Re: Fuel pressure = 75PSI...on a stock 4AGE????Can anyone help me out with this? Mon, 28 November 2005 04:24 Go to previous messageGo to next message
Specialty tool? It's just a pressure gauge. I have a VDO electronic oil pressure gauge hooked up to the fuel rail on my 18R-GEU, it works nicely and was handy when diagnosing problems with my fuel system.
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WHITCHY
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August 2003
Re: Fuel pressure = 75PSI...on a stock 4AGE????Can anyone help me out with this? Mon, 28 November 2005 04:41 Go to previous messageGo to next message
So I should be able to just buy an electronic oil pressure guage and hook that in to test it?
How did you hook it into the line?
Thanks.
-Whitchy-
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oldcorollas
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January 2003
 
Re: Fuel pressure = 75PSI...on a stock 4AGE????Can anyone help me out with this? Mon, 28 November 2005 04:44 Go to previous messageGo to next message
Norbie wrote on Mon, 28 November 2005 14:48

What fuel pump are you running? If it's a big aftermarket one it's quite possible it's pushing too much volume for the stock lines/regulator to handle.


i was using a 190L walbro pump (155 at 40psi) with a camry/celica reg of some sort.... off've a 3S something.. most of the toyota ones i saw at pickies seemed to have similar looking ones... both regs and dampers, with the main difference in the piping from the bajo fittings..


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WHITCHY
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Castle Hill
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Re: Fuel pressure = 75PSI...on a stock 4AGE????What are my options for running new fuel lines??? Mon, 05 December 2005 12:11 Go to previous messageGo to next message
Ok, so I finally had the time to pull the return line off and stick the air compressor nozzle down there and blow the blockage away...no luck! It wouldn't budge!
I had the fuel cap off so the air should have just blown the blockage through and the air shouldve come out the filler hole, but the pressure just built up and forced the nozzel out of the return line! so something big is blocking it or there is a pinch in the line somewhere!

So, I am just wondering what my options are if the return line is rooted, or unblockable.
Is it legal to run rubber fuel line all the way along the bottom of the car?or is that too dangerous cause they could puncture too easily?its efi hose so its thick?
and also would it be cheaper/safer to just get a new return line made up?
and can anyone suggest places to go to get the lines made up?

or are there some other options that I can look at?
I am going away on Friday so I am aiming to get it all fixed by then so I don't waste a shitload of money on petrol getting a whopping 200kms to a tank.

Thanks heaps for any info and advice!
Cheers.
-Whitchy-

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thechuckster
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Re: Fuel pressure = 75PSI...on a stock 4AGE????What are my options for running new fuel lines??? Mon, 05 December 2005 13:05 Go to previous messageGo to next message
WHITCHY wrote on Mon, 05 December 2005 22:11

So, I am just wondering what my options are if the return line is rooted, or unblockable.
Is it legal to run rubber fuel line all the way along the bottom of the car?or is that too dangerous cause they could puncture too easily?its efi hose so its thick?
and also would it be cheaper/safer to just get a new return line made up?


no - is not legal, nor is it safe (even using EFI hose) for the very reason you point out.

it might be easier to go to the wreckers and remove the return line off a wreck - bugger paying/making you own new line.

i recall people100 doing this for his old TA22 - except he removed all the lines from the wreck (while you're under the car, gettingdust/n-shit all over you, you may as well grab anything else that might be faintly useful)

have you had a look under the car to look for spots where it might have been squashed?
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mic*
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Location:
Brisbane
Registered:
July 2005
Re: Fuel pressure = 75PSI...on a stock 4AGE????Can anyone help me out with this? Tue, 06 December 2005 00:01 Go to previous message
Norbie wrote on Mon, 28 November 2005 14:48

What fuel pump are you running? If it's a big aftermarket one it's quite possible it's pushing too much volume for the stock lines/regulator to handle.



In line with what stu said tho, you would think the regulator would either regulate, or fuck up and free flow, giving pressure drop...

When did you last, clean the tank? Replace fuel filter?

Blocked return still seems most likely, but the fact that you said it worked for 10min makes me think possibly that crap is getting pushed into the regulator and restricting it.



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