VP 5.7 won't stay running

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Ericsh230

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05 h230 5.7 gxi-f. Brand new engine. Won't stay running. Only about 5 seconds. Almost all new parts. Fuel pump, oil pressure sensor, ect. It's getting fuel, pressure is good at the rails. It ran for about a minute after new pumps. Ran shorter each time. Now only a few seconds. Cleaned fuel pressure regulator. Antisiphon is good. Fuel tank is full. We are stumped. Anyway to pull diag codes from this motor?
 
alldodge

alldodge

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Place fuel pressure gauge on the rail and see if the pressure starts dropping right after it starts
 
Scott Danforth

Scott Danforth

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also check wiring harness to make sure diode at back of alternator that feeds fuel pump when engine is running is not blown
 
alldodge

alldodge

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Trying to find out what is causing the shut down, we don't know yet.

If the relay is being turned off at least we know the problem, then need to figure out why. If its not fuel then that's a place we don't need to look.
 
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Ericsh230

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alldodge said:
Trying to find out what is causing the shut down, we don't know yet.

If the relay is being turned off at least we know the problem, then need to figure out why. If its not fuel then that's a place we don't need to look.
Click to expand...

Ok. After priming the pump a few times the pressure at the rail goes to about 9 psi. The engine will not start now. After a couple tries the pressure slowly goes to zero.... I even pulled the filter and filled it up then primed about 5 times.
 
Scott Danforth

Scott Danforth

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9 psi? fuel injected engines are either 1-bar (15 psi), 2-bar (30 psi) or 3 bar (45 psi) systems

most throttle body systems are 1-bar
all Multi-port systems are 3 bar systems
 
Scott Danforth

Scott Danforth

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BTW, your 5.7 gxi-f should be 43psi minimum
 
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Ericsh230

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So what could be limiting the psi? I've had 2 pump assemblies on it with the same results...... btw this was taken on the rail where it crosses over on that Schrader valve.
 
alldodge

alldodge

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Some info has to be missing

Brand new motor and everything from tank to fuel rail has been checked. Its getting fuel but pressure is only 9 psi

After HP pump fuel goes to the fuel rail and any pressure which exceeds the regulator goes back to the low side of the LP pump.

Only thing which keeps pressure from building is Regulator, HP pump, no fuel, leaking injectors or leaking fuel line

So what part of what has been said may not be 100% ??
 
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Ericsh230

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That's been my frustrations. I've had multiple machanically inclined people look it over. Mult forum posts. I'm stumped...... maybe need to remove rails and injectors and have them cleaned? IDK. That doesn't explain the low fuel pressure tho.
 
alldodge

alldodge

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Clean and flow test the injectors can always be a good thing for ones which have not been done in some time. Injectors which leak so much that the pump cannot build pressure would mean the motor would be flooding with fuel. What fuel didn't come out the exhaust would wash down the cylinder walls and wind up in the oil pan.

The oil level would be coming up

Are all the fuel lines connected in the correct places?
 
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