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502 efi issues please help w/ suggestions?

Old 07-04-2012, 11:35 PM
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Default 502 efi issues please help w/ suggestions?

93 502 efi, motor always fires the first time idles fine say putting in @ the ramp or tied up or whatever.... Put it in drive idle out of say an idle zone that's 5 minutes long go to get up on plane starts getting some RPM's & it will just cut out & stall. Go to restart & won't fire, play the waiting game tryin periodically to start it & eventually it fires put it drive & give her some throttle gets on plane runs great the rest of the time?

I'm clueless, when it stalls & won't refire it's like it's not getting fuel & it has done this multiple times? Then randomly turn the key & boom starts & runs fine....
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Old 07-04-2012, 11:56 PM
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check your fuel pressure to know. check grounds and power connections, check ignition.
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Old 07-05-2012, 07:52 AM
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sounds familiar

http://www.offshoreonly.com/forums/g...2-fueling.html
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Old 07-05-2012, 05:45 PM
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fuel pressures good, grounds & power connections wouldn't do it on the same exact scenario everytime & would do it itermenitally while driving. I was always told once the motor is running it would no longer vapor lock, is that true?
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Old 07-05-2012, 06:27 PM
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When it will not start do you hear the fuel pump prime each time you turn the key to the ON position?
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Old 07-05-2012, 07:07 PM
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Not sure will check asap.... I believe it's vapor lock! But like I said, I've heard once they are running they no longer will lock up? Just need to know if this is true, or if it's possible for them to lock up @ low RPM's other than idle!
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Old 07-05-2012, 07:21 PM
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I Had mine do that to me once, it started, idled, then died after a few minutes. I am adding a boost pump tomorrow. do you have the raw water mounted fuel pump or just the one pump?
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Old 07-05-2012, 09:38 PM
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Impellar pump mounted fuel pump & the electric vst pump on top!
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Old 07-05-2012, 09:47 PM
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It probably is vapor lock, with a low pressure system like a carbed engine once it starts it will no longer vapor lock. But in a fuel injection system you can maintain pressure without actual fuel volume (foam basically) and the rails will have too much air in them to allow the engine to run on the very short injection pulse. If you still here the pump prime each time you turn the key on, find the shrader valve on the fuel rail and release some fuel/vapor into a rag. If it comes out in little spurts key on a few times till you get liquid fuel and it should start.
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Old 07-05-2012, 09:52 PM
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Thanx Ted....
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