350 mag mpi not starting

carisabo

Recruit
Joined
Aug 21, 2017
Messages
3
hopefully I can get some help from one of you fellas. I have a 2004 tige direct drive 350 mag mpi. at the lake the other day and ran beautiful until It was time to leave ( of course) and started fine and a few seconds into idle it started idleing really rough and died. tried restarting and I could get it to kinda run barely by messing with throttle, now I initially thought it was a bad IAC but after getting it home I hooked up my fuel gauge to the rail and when I turn the key I can hear the pump prime for a few seconds but the fuel pressure only goes to 10 psi. is that normal? I thought with key on it should be around 40? any thoughts?
 

carisabo

Recruit
Joined
Aug 21, 2017
Messages
3
I know it has the vacuum style regulator on the rail, if that fails will it just let the fuel flow freely back to the tank? also another weird thing is when I turned the key to on the volt gauge reads 12 volts then when the computer does its initial beep it drops to 10. I'm charging both batteries now but just seemed weird it would read 12 then after the beep it goes down to 10 and my perfect pass just turns on and off on and off on and off.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,469
I'm charging both batteries now

Ayuh,..... Welcome Aboard,.... Pull the terminals, 'n Clean 'em to shiny metal Clean, includin' the Grounds,...

Yer problems sound Ground related,...

Do both ends of both cables,...
 

carisabo

Recruit
Joined
Aug 21, 2017
Messages
3
well thanks gents, problem solved. so turns out the 2 wire push connector on the back of my alternator came off some how some way, so basically drained both batts to the point were it would turn over enough to bust off but didn't have enough power for the ecm to work correctly I'm guessing. so that answers the battery issue, so for the other problem with it not starting after fully charged. well I remembered I pulled the fuel water filter/separator at the lake thinking I would check that when i couldn't keep it idling. so I was sitting there last night looking and thinking and I thought since the pump is coming on with key turned for a few seconds so I know its turning but no fuel pressure. I ended up bleeding the fuel through my gauge and bleeding off a lot of air bubbles. apparently when I put the "empty" fuel filter back on on it was enough air to air lock the pump. once I bleed fuel and air through it finally got up to 45 psi. Got her fired up but has some missing goin on, so I'm thinking a plug change is in order. prolly fouled one or two pumping the crap out of the throttle. and I know pumping a fuel injected motor sounds dumb but it was a spur of the moment instinct from carb days. but all in all I think I got it worked out. thanks for the help
 
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