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502 mpi running on 4 cylinders

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502 mpi running on 4 cylinders

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Old 05-04-2013 | 08:00 PM
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Default 502 mpi running on 4 cylinders

Ran the boat today made a couple laps at WOT, headed back and it hiccuped so I backed out of the throttle then started running like s*** after putting a new cap and rotor and a coil still running the same

After some trouble shooting 2 cylinders are down on th port and starboard side

Port side cylinders 1 and 7 are down
Starboard side cylinders 4 and 6 are down

Any ideas? I'm thinking a distributor but not sure
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Old 05-04-2013 | 08:29 PM
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sound like an injector wire feed from ecu went bad.
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Old 05-04-2013 | 08:42 PM
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So is that the injector harness that runs cylinders 1746?
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Old 05-04-2013 | 09:17 PM
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Originally Posted by tdpb2008
So is that the injector harness that runs cylinders 1746?
sounds like it.there are 2 driver circuits from the ecu.also check the 12v feed to them also.
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Old 05-04-2013 | 09:20 PM
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Ok will do
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Old 05-04-2013 | 09:24 PM
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How would I test these? And where
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Old 05-04-2013 | 09:40 PM
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Originally Posted by tdpb2008
How would I test these? And where
at the injector w/ a noid light.
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Old 05-04-2013 | 10:30 PM
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I am looking at my wiring harness for another problem but you might check your grounds. There are 3 grounds on the injection harness alone. Randy
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Old 05-05-2013 | 07:23 AM
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It's weird it was running great then it hiccuped and has run on 4 cylinders...they just all of a sudden go?
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Old 05-05-2013 | 07:59 AM
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I just checked the spark and it does have spark on all cylinders
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