fuel leak down, at a loss?
12-08-2009, 10:29 AM
#1
in limbo
Thread Starter
Join Date: Jan 2007
Location: Iowa
Posts: 7,300
fuel leak down, at a loss?
ok i'm hooking up nitrous right now but i have this eerie feeling if i dont address this issue now....i'll be doing a rebuild of the motor in the near future. hahahha!
ok here is the deal, i turn key on the FP jumps to 40psi, turn the key off and it takes approx 10sec for all FP to leak down. ok...well here is what i did for a test.
test 1)key on, key off, then i pinched off the rubber return line. FP still leaked down in approx 10sec.
test 2) key on, key off, then i pinched off the feed line before and after the fuel filter, FP still leaks down in approx 10 sec.
i cant find a single wet fuel line, drip or anything along the entire length of feed or return line. where else could i be having leakdown at that i wouldnt see it?
i dont think its my fuel pump because its new (walboro 190lph) and my test eliminated it as an option of bad check valve or split line in the tank. opinions? tests? anything? halp! i wanna spray this beotch!
side note for more info*
it take excessive cranking or multiple cranks before firing. the FP will dropp from the initial 40psi to about 10psi when cranking until it finally fires. then it jumps back to 40psi and bounces back and fourth from ~40-30psi when it finally decides to idle. once the car has been running for a minute or so the flucuation stops and holds constant 30psi. if i take the car out. WOT the PSI constantly increases with no sudden drops. on deceleration, no flucuation or sudden increases or decreases.
wtf?
ok here is the deal, i turn key on the FP jumps to 40psi, turn the key off and it takes approx 10sec for all FP to leak down. ok...well here is what i did for a test.
test 1)key on, key off, then i pinched off the rubber return line. FP still leaked down in approx 10sec.
test 2) key on, key off, then i pinched off the feed line before and after the fuel filter, FP still leaks down in approx 10 sec.
i cant find a single wet fuel line, drip or anything along the entire length of feed or return line. where else could i be having leakdown at that i wouldnt see it?
i dont think its my fuel pump because its new (walboro 190lph) and my test eliminated it as an option of bad check valve or split line in the tank. opinions? tests? anything? halp! i wanna spray this beotch!
side note for more info*
it take excessive cranking or multiple cranks before firing. the FP will dropp from the initial 40psi to about 10psi when cranking until it finally fires. then it jumps back to 40psi and bounces back and fourth from ~40-30psi when it finally decides to idle. once the car has been running for a minute or so the flucuation stops and holds constant 30psi. if i take the car out. WOT the PSI constantly increases with no sudden drops. on deceleration, no flucuation or sudden increases or decreases.
wtf?
Last edited by FivePointOhh; 12-08-2009 at 10:36 AM.
12-09-2009, 09:22 PM
#4
5th Gear Member
Join Date: Oct 2007
Location: Georgia
Posts: 2,624
I actually checked my fuel pressure today cause I was wondering why it was always so hard to crank. I hooked everything up switched the car to the run position and the neddle didn't even move, so I started it:the first crank it doesn't start and the second it fires right up and the pressure sits at about 34 psi and when I take the vac line off the reg. it jumps up to 40. As soon as I shut the car off,within 2 sec. the pressure drops to 0. I asked my teach what he thought and said he thought mine was the f/p because of how fast it dropped,he said it takes longer if its leaky injectors
12-09-2009, 09:22 PM
#5
The Rogue Mod
Join Date: Feb 2006
Location: Maryland Sucka's!!
Posts: 21,918
Yup, that would also explain extended cranking if there is excessive gas in the cylinders. You would have to pull them, then w/ the lines connected, energize the key to build pressure, then watch to see which one/s are leaking. Any black smoke on start up?
12-09-2009, 09:24 PM
#6
The Rogue Mod
Join Date: Feb 2006
Location: Maryland Sucka's!!
Posts: 21,918
I actually checked my fuel pressure today cause I was wondering why it was always so hard to crank. I hooked everything up switched the car to the run position and the neddle didn't even move, so I started it:the first crank it doesn't start and the second it fires right up and the pressure sits at about 34 psi and when I take the vac line off the reg. it jumps up to 40. As soon as I shut the car off,within 2 sec. the pressure drops to 0. I asked my teach what he thought and said he thought mine was the f/p because of how fast it dropped,he said it takes longer if its leaky injectors
12-09-2009, 09:30 PM
#7
5th Gear Member
Join Date: Oct 2007
Location: Georgia
Posts: 2,624
I cycled it maybe 3-4 times, but I'll end up keeping the pump in the car until I buy the 255 pump for the turbo or until it goes out in which case makes for a good time to buy the fuel pump
12-09-2009, 09:53 PM
#8
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
leave the return clamped then go clamp off the filter, if it still leaks down it's an injector....pull up the injectors and lay them on a paper town and retest and you should see the culprit
12-10-2009, 09:25 AM
#9
in limbo
Thread Starter
Join Date: Jan 2007
Location: Iowa
Posts: 7,300
so just unbolt the fuel rail, pop the injectors out of the bungs of the intake...lay a paper towel under the injectors and cycle the key on and watch?
it makes sense that its the injectors because of how the car acts on first start up. if you step on the gas pedal to rev the engine, it acts like its loading up. i'll check this issue out. hopefully you guys are right
it makes sense that its the injectors because of how the car acts on first start up. if you step on the gas pedal to rev the engine, it acts like its loading up. i'll check this issue out. hopefully you guys are right