GT-40 Hard starting after sitting a few minutes |
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lewy2001
Grand Poobah Joined: March-19-2008 Location: NSW Australia Status: Offline Points: 2234 |
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Posted: September-13-2013 at 9:28pm |
Josh if you look towards the bottom of the first page of threads in the Engine forum you will see another GT40 not starting thread.
Here is a insert from it discussing fuel pressure (injector) leakdown testing. "Just to confirm, when it will not start you have approx. 40psi fuel pressure and the pumps are performing their prime cycle. The manual states the fuel rail should maintain within 3 psi of the approx 40psi for 3 minutes. I would jumper the STO and run the pumps for 30 secs to get your initial 40 psi for this leakdown test." |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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You shouldn't need to crank since the pumps are electric. But, you will need to turn on the ignition to build initial pressure.
If you can update the subject to this thread, add "GT-40" to it. Then hopefully some more of the real GT-40'gurus will pick up it and chime in as well. |
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jbach
Senior Member Joined: September-24-2012 Location: Kentucky Status: Offline Points: 140 |
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quick question. i read in the GT-40 manual the pressure at the rail should be 31 lbs. +/- 3 lbs. do i need to initially crank the motor to build this pressure from cold or should the rail always stay pressurized?
If it is not pressurized, how long should it hold that pressure? If it does not hold, it could only be leaky injectors or bad fuel pressure regulator right? there may be a faint smell of gas in the oil and i think Brian may have hit the nail on the head. it doesn't look thin to me but, not 100% sure. |
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jbach
Senior Member Joined: September-24-2012 Location: Kentucky Status: Offline Points: 140 |
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i never even though of that. i don't even remember if the GT-40 has fuel rails, but would pulling the injectors and cycle the ignition on diagnose that problem? stick a piece of cardboard under them to see if they are leaking?
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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There's the possibility fuel could be leaking from the injectors into the manifold.
Are you getting any extra smoke when it finally does start up? |
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jbach
Senior Member Joined: September-24-2012 Location: Kentucky Status: Offline Points: 140 |
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it's not that bad, and has not left me stranded, but it is fuel injected and the problem has just surfaced recently. it has just always started effortlessly and am thinking something is close to failing and would like to nip it in the bud before that time comes.
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Dreaming
Platinum Member Joined: May-21-2010 Location: Tacoma, WA Status: Offline Points: 1870 |
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I would suggest ASV as maintenance as you have suggested, but go buy that fuel pressure guage anyway. 4-5 seconds of cranking doesn't sound too bad to me....
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jbach
Senior Member Joined: September-24-2012 Location: Kentucky Status: Offline Points: 140 |
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i'm having a little bit of hard starting issue with a '99 SAN with GT-40 engine. the boat fires up instantly when cold, just like it always has. this summer i've had some hard starting (cranking 4-5 seconds) after the boat has been sitting 10+ minutes. if i shut it down and immediately restart like with in a minute, it does so just fine.
i've changed the FCC filter and hose and did a full tune-up this spring (cap & rotor, plugs, wires). i also replaced both relays. i'm going to pull the anti-siphon valve tonight and clean it. could this be sticking open, draining the fcc causing it to turn over that long? it would seem to me there would still be fuel in between the fcc and injectors to be able to start on? plus doesn't make sense that it starts perfectly when cold. i also was thinking maybe bad coil when hot? that also doesn't add up that it would start immediately after shutting down just fine. if cleaning the AS valve doesn't work, i'll go buy a fuel pressure gauge and make sure it's making enough pressure. anything else i need to try? |
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