Fuel and Ignition Fuel Pumps and Systems, Ignition and Spark Systems

no start, fuel pressure bleeds off

Old 09-22-2015, 02:00 PM
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no start, fuel pressure bleeds off

98 z28 that ran fine (sorta but it at least started) after I installed a new 6.2 LS3. After sitting in garage for 6 months, it wont start. I have a fuel gage on my fuel rail and it will get 65 lbs of pressure when I turn on the key, but the pressure bleeds off slowly. I have a new fuel pump installed when I installed new engine. Is there a pressure regulator in this system? What am I missing?
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Old 09-22-2015, 04:50 PM
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Re: no start, fuel pressure bleeds off

Some pressure bleed down is normal. On the LS1 cars, the fuel pressure regulator is back at the tank, and bypasses fuel back to the tank to control pressure. The system is "dead-ended" with no return from the fuel rail.

Try cycling the key rapidly between "off" and "run" a few times, before turning it to "start". That will sometimes help it start quicker. But gradual loss of pressure usually does not prevent it from starting, only extends the cranking time before it starts.

Is it possible your fuel is stale?
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Old 09-22-2015, 11:16 PM
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Re: no start, fuel pressure bleeds off

Does the car start then shut down?The ethanol in the gas separates over time(just go to Jay Lenos web sight ,he has had to drop half the gas tanks on his 180 vehicles from non operation because of this.)Also condensation builds up in not a full tank of gas with no gas stabilizer .Worth checking out anyway.Hope this helps.Like Injuneer suggested,the gas has gone south maybe.My02.
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Old 09-23-2015, 01:08 AM
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Re: no start, fuel pressure bleeds off

Originally Posted by Injuneer View Post
Some pressure bleed down is normal. On the LS1 cars, the fuel pressure regulator is back at the tank, and bypasses fuel back to the tank to control pressure. The system is "dead-ended" with no return from the fuel rail.

Try cycling the key rapidly between "off" and "run" a few times, before turning it to "start". That will sometimes help it start quicker. But gradual loss of pressure usually does not prevent it from starting, only extends the cranking time before it starts.

Is it possible your fuel is stale?
I have Stabil in it. And I also put 6 gallons of fresh fuel in it just to make sure it had plenty of good fuel. I tried the key cycling several times already and it didn't try to start. I sprayed a small shot of starting fluid in it and it fired and ran for about 2 seconds so I am sure it is fuel problems, not ignition.
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Old 09-23-2015, 01:12 AM
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Re: no start, fuel pressure bleeds off

Originally Posted by Fatdog2 View Post
Does the car start then shut down?The ethanol in the gas separates over time(just go to Jay Lenos web sight ,he has had to drop half the gas tanks on his 180 vehicles from non operation because of this.)Also condensation builds up in not a full tank of gas with no gas stabilizer .Worth checking out anyway.Hope this helps.Like Injuneer suggested,the gas has gone south maybe.My02.
Fatdog, it cranks but wont even try to start. I have the fuel pump out and am doing some checking to see if I can find anything wrong there. Had to go to dinner with family so I didn't get to finish. I will do some more looking and checking tomorrow morning.... Thanks!!!
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