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  #1  
Old 04-13-2006, 08:04 PM
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Default Easiest way to relieve fuel pressure

I want to change the fuel filter and want to know the best and easiest way to relieve the pressure in the fuel system to allow for the filter change. 2000 4.3L CPI not that that would make any difference. Someone told me you just have to remove the gas cap but I dont' think that is accurate. What about the Schrader valve behind the throttle body, between it and the dist.? Can you just use a screw driver or better yet a small dis. wooden dowel?

If I just crack loose the nut on the inlet side of the filter will that work or blow gas all over along with damaging something?

tia
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  #2  
Old 04-13-2006, 09:58 PM
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Default RE: Easiest way to relieve fuel pressure

I do this by pulling the fuel pump relay and attempting to start the engine. It probably won't start, but you also won't get fuel anywhere other than when you pull the filter... But atleast it won't spray.
  #3  
Old 04-13-2006, 11:41 PM
 
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Default RE: Easiest way to relieve fuel pressure

Sounds like a better way than actually looking for the silly little valve that is found on some of these cars. Can never be quite sure where it is and sometimes its hiding so far down its impractical to use it. I see you found it< USE IT. Yes a small anything that wont damage it will work fine. Engine off, cap open, use valve. DO NOT BELIEVE THE PRESSURE IS GONE. Be careful.

I have a bad habit of not doing anything like that, I just turn the wrenches SLOWLY while wearing safety glasses. NOT the right way. I do have an excuse, I want to see the fuel that comes out, and I dont want it to stay in there either. I repeat, not the right way.

Be aware that a small air valve looking (Schrader) kind of thingy may well be on your motor in the fuel line to release pressure. If you have a book that tell you to do this then I hope it also tells you where it IS???? Many books will have instructions on how to do this for individual motors. I would rather see folks using them, but I have a terrible time finding them. (This is written for the general public that reads these posts.)


Just 2 days ago I had the audacity to start removing the fuel injection on a 2.8. I needed to get the manifold off; taking whole engine apart. So I get the darn TOP off and (Oh this had 6 injectors, whatever) here I finally see the silly fuel pressure relief valve. I couldnt believe how far I had this thing apart before I found it. I had taken a large pair of cutters and snipped right straight through the rubber sections of the high pressure lines and DARN SURE HAD RELIEVED the pressure, HAHA. By the time I found it, it was on an engine stand. I always cut all hoses, when removing donor parts, even brake lines, so I dont use them over.

Dont do what I do, do what I say!!!!!!
  #4  
Old 04-14-2006, 01:50 AM
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Default RE: Easiest way to relieve fuel pressure

Actually I have found it and it is directly behind the throttle body in from of the dist. I have an old setup from my diesel days that was for pressure testing the holes. The attachment matched a Detriot injector. Big ol' SOB too.. but it has the quick disconnect on it already and all I need is the schrader as it has a guage n it already too... I would just like to find out exactly what valve fitting I need to fit over the valve to may it fly. Thought someone miht have the info..
TIA
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Old 04-14-2006, 02:06 AM
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Default RE: Easiest way to relieve fuel pressure

i've heard the gas cap thing too... i dont know if the schrader valve would relieve pressure, but if it did you'd have to let out quite a bit
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  #6  
Old 04-14-2006, 07:20 AM
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Default RE: Easiest way to relieve fuel pressure

I can relieve the pressure with my fuel pressure gauge as well, but then I have to clean out the gauge... LOL I'm lazy. I'd rather pull the relay. I'd have to take a look at the paperwork that came with my gauge to see what size the valve is.
  #7  
Old 04-14-2006, 11:43 AM
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Default RE: Easiest way to relieve fuel pressure

swartlkk>>
If you could do that for me at your convenience I would appreciate it. I would like to confirm that pulling the gas cap off is all I have to do to relieve pressure to facilitate the filter exchange? I want to be sure that the little quacks are in a row before I delve into this. I know it is only a damn fuel filter, but I just don't want any problems or to screw something up.
tia
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2000 LT 4.3L, 2WD,
1999 Saturn SW2 ??
1972 .75t Cheyene Super 402/350/327
2003 FLSTF (FATBOY/Heritage)aka FATITAGE 88'(for now)
1969 ElectraGlide (Custom) BIG (sold)

Organ Donation: The Gift of Life
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  #8  
Old 04-14-2006, 12:32 PM
 
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Default RE: Easiest way to relieve fuel pressure

Removing the gas cap won't do it for you. My Haynes manual just advises to place a towel over and around the valve with room for a screwdriver to depress the thing. I did this and it worked just fine, the rag caught all the fuel. I have also pulled the fuse for the pump and cranked the engine a couple of times and this worked too. Either way, use eyeware as there is a good amount of fuel left in the filter that will come out.
Will
  #9  
Old 04-14-2006, 02:07 PM
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Default RE: Easiest way to relieve fuel pressure

Okay, one last question and this IS a stupid one,... but..... after taking loose the nut and fitting from the fliter, what keeps the fuel in the tank from running?
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2000 LT 4.3L, 2WD,
1999 Saturn SW2 ??
1972 .75t Cheyene Super 402/350/327
2003 FLSTF (FATBOY/Heritage)aka FATITAGE 88'(for now)
1969 ElectraGlide (Custom) BIG (sold)

Organ Donation: The Gift of Life
Please get and sign a donor card
  #10  
Old 04-14-2006, 05:16 PM
 
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Default RE: Easiest way to relieve fuel pressure

I think that's a good question. I'd say keeping the fuel filler cap on would do it. Kinda like keeping your finger on the end of a straw, it prevents air from filling the potential vacuum of the exiting fluid.
Will
EDIT: plus, the fuel line exits out the top of the tank and then curves down, so only the fuel in the line that's below the tank fluid level would leak out, not the whole tank.
Old 04-14-2006, 05:16 PM
 
 
 
 

Tags
1972, 1999, 2003, 93, blazer, chevy, fuel, pressure, relieve, relieving, relive, s10, schrader, siphon, size


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