running, died, no audible alarm,started, same thing again, help please........

[splashed]

98 mercruiser 7.4 mpi. bravo1 as stated in title out cruising around and engine died, no audible alarm went off, turned off and turned key back on with no alarm at all , it would normally give the all clear alarm at start up. tried to crank up anyway and all it did was crank, no start. waited 20 mins. turned key on and got normal all clear alarm cranked and started. ran at idle about 2-3 mins did it all over again. oil pressure @40 idle, temp. @ 170, idle @ 600 rpm, new water/fuel sep. foot oil level on full. engine oil level on full. it acted like there was no power, no fuel, no spark , no go go anywhere. cranked and started back at home for about 2-3 minutes and continued the same problem. my wife says she noticed the rpms bounced from 1500-2300 in the driveway after it was all said and done. thanks in advance for your knowledge and help. i have been lurking on here awhile and have used alot of your info. jeff

 

[Don S]

Re: running, died, no audible alarm,started, same thing again, help please........

Just after it dies, and you turn the key on, do you hear the fuel pump run for a couple of second?
Also, just after it dies, you need to check to see if it has spark.
When you replaced the fuel filter, did you check the old one to see if there was water in it? IF not, you may need to pull the filter and pour it into a clear container and check for water in the fuel. Install a new filter, do not reuse a fuel filter after it's removed.

 

[splashed]

Re: running, died, no audible alarm,started, same thing again, help please........

no fuel pump until it gives the all clear alarm and no water to speak of in the filter. have not checked the spark issue when it died,

 

[Don S]

Re: running, died, no audible alarm,started, same thing again, help please........

You are going to need to get it hooked up to a diagnostic computer to see what is happening.
When it dies, you might try a wiggle test of all the connections to see if something brings it back to life by moving it.

 

[splashed]

Re: running, died, no audible alarm,started, same thing again, help please........

i appreciate you looking at the problem, i'll see what can be done with diag. and post back the solution if i get one from them.

 

[bloodyknuckletech]

Re: running, died, no audible alarm,started, same thing again, help please........

You have relays back by the ecm that could cause this issue..there back by the ecm that year sounds like a mefi 3 ignition system..if those relays..there's a fuel relay anda main power relay..if they start to fail.. it will give you the problems you listed check volts with key on at the purple and yellow red wire at the back of the alternator if there's no volts there check back at the ignition switch and cycle on off a couple times as it could be the ignition switch..your killswitch would also cause those problems if its on its way out..cycle that on off a few times key on

 

[Pete104]

Re: running, died, no audible alarm,started, same thing again, help please........

10 pin connector! Your main harness from "engine to helm", can make a nice running engine, NOT!

 

[splashed]

Re: running, died, no audible alarm,started, same thing again, help please..FIXED!!

Re: running, died, no audible alarm,started, same thing again, help please..FIXED!!

thanks for the additional info, i'll look into those areas as soon as possible. found that the electronic ignition relay was heating up and shutting down, replaced and all is as it should be, good. thanks for your knowledge and helpful advice.