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2004 5.0 MPI wont start

J

jerry485

New member
engine shut down while cruising. tried to start , nothing. when the key is turned on,i get an audible check alarm. i dont here the usual humming of the fuel pump. could it be a relay? please help!
 
Start with disconnecting the main engine plug and inspecting it for corrosion. If no corrosion is found, re-seat the plug and tighten the clamp. Test the engine. That is where you start.
 
i took all the plugs apart & they look great no corrosion. i took apart the plug conn. for the fuel pump, put a volt meter on it had the wife turn the key. the audible test alarm soundedbut no significant volt. at the conn.at the pump(.04volts) the book says it should read 12-14 volts for 2 sec. then go to 0. it didnt do that! isuspect a relay. may i please have your thought?
 
There is a main power relay on the engine. If this relay goes bad nothing will work. Put your meter across the fuel pump power feed again and have the wife tap the key to crank the engine over. See if you have power at this point.
 
will it crank over or do nothing? is it an alpha 1 or bravo? have you checked the safety lanyard? are you sure its in neutral?
 
it could be a relay. it could be a fuse as the relay for the pumps also is fused, it could be the safety lanyard as on the injected motors it shuts down fuel pump, you arnt getting a prime pulse so if the computer is sending a signal for the prime pulse these components can stop the power getting to the pump.
 
just got in. i want to thank all you guys for your help. we're dealing with a 5.0 2004 merc crsr alpha 11 drive. i attempted to start it awhile ago. turned yhe key, got the 2 sec. buzzer,turned the key to start, heard the pump started for 3 seconds then shut down . tried to re start, it wouldnt. tomorrow is another day! thanks guys!
 
Start procedure is key on one minute ( allows air valve to change position) then start. Also GM system has a delay between starts. Have to wait (? seconds) to try again.
You should have +12v on pump. EFI control supplies the ground to make it run.
 
Just want to be sure the motor doesn't crank at all ?

" shut down while cruising " Kill switch got pulled ? Pull it and reset it a couple of times maybe.

Look at the starter there should be a reset on top or a fuse able link.
 
I just had a similar problem with my 2005 5.0 MPI where I turn the key, hear the fuel pump, but no motor rotation occurs. After rapidly turning key off and on it started about the 12th time (I lost count). Turns out there's a solenoid for the starter that's located atop the manifold. Inexpensive $23 part and $112 for labor to repair. If I had known where the solenoid was located I could have saved $112.
 
i got a new fuel pump relay, put it in , turned the key to on , heard the 2 sec. horn & fuel pump. turned to start, itfired right up. huuurayyy! NOT! came back on idle ,it stalled, & wouldnt start again... itried to start it again. this time when i turned the key to start position the engine cranked & at the same time i heard 1 single beep. put the cover on & took it to the dealer.(may GOD have mercy)
once again THANK YOU to all who helped. ill let you know the result.
 
i got a call from the merc. dlr. he said i needed a crankshaft pos. sensor & a E.C.M. total cost w/ labor $2126.00. WOW cant believe it!the boat has 325hrs. well maintained, now this. makes you want to get out of boating! anyway i dont give up easy. i told the merc. dlr. to button it up ill be in to pick it up.
is there anyway to test the ECM if i remove it? can i send it anywhere to get tested? i was also contemplating geeting rid of the whole electronic end & put it back with the good old carb, without all the sensors & B>S> associated with a ccomputer! i plan on calling mercruiser myself & ask some ????.
iam at the end of the rope. anyone have any suggestions?
 
This is a very old string, how did it turn out? I have a 5 litre Mercruiser- Alpha 1- about 2000 vintage. I ran great, this spring randomly the alarm came on and stayed on when key turned on, engine cranks, but does not fire. Alarm is on all the time. When you crank it magically started, on 2 occasions and ran well for the day. We jiggled the kill switch which seemed to coincidentally make it work after some time. Now everything try with the kill switch or putting in in and out of gear does nothing. :(. batteries OK and there is 12 V at the coil, but there is no fuel coming out of the 2 throttle body injectors.
 
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