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Mercruiser 5.0 MPI Cut out and stalls for no reason...

D

dubie

New member
I have a 2002 Mercruiser 5.0L MPI Engine
Ser# OM351757

It starts and idles great. Problem is it cuts out for no apparent reason. Like someone turned key off. Put it in neutral and it immediately starts up with no hesitation and out of the hole no problem. Very random shut off. It will sometimes do it everry couple minutes and sometimes be good for an hour.
I have taken it in twice to dealer with no results. Unable to get it to do this in shop. There are no engine fault codes recorded.
We have changed fuel pump, filter with same results.

I have cleaned battery connectioins and wiggle tested all the wire harneses. Checked kill switch.

Like I said, it starts immediately and takes off like nothing happened, no audible alarms.
Tested battery voltage and it is 14.48Volts while running so that seems fine.

Any help would be appreciated, I think my next step is to change the ECM or maybe the IAC valve?????
Guys have said on other forums that the ECM on this engine is known to be faulty????

Just want to check every thing possible before I drop the big bucks on the ECM that is not refundable.
 
You can clean the IAC. Disconnect the battery and then the ECM. Before I purchased another ECM I would open it up and check every solder joint w/a mag. glass and resolder those that were suspect...look for cracks in the circuit board where the harness connects and on the backs of the board(s). If you aren't qualified to do it then find a reliable electronics repair shop and see if they will look at it for you.
 
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boat_tech said:
Wondering if your mercruiser dealer did the test in the service bulletin your engine serial number falls under.

Try or have the dealer try the test on page 3/3 in the bulletin below.
http://www.marinemechanic.com/merc/distributors/mercurymarine/sterndrive/gmefi-nostart.PDF

If it works, Try unbolting the shift plate off the engine so it won't vibrate and see if the engine runs normal.
Click to expand...


Thanks for all your suggestions. I will try this test in the service bulletin. Looks easy enough to test with a jumper wire.

Won't get the boat in the water for a week or so but will definetly report back what I find after this.
Thanks again
 
crummy said:
Let me know what happens. I have 4 that are doing the same thing.
Click to expand...


Jumper wire as per service bulliten fixed the problem. Have ran it with jumper wire and no issue since. Have not yet bought the new ECM yet.
Hope that helps you out.
 
My boat would not stop but would go a reduced speed and the alarm would go off. I do not have limp mode on my engine My ECM is a MEF1 I just had work done on my 1997 Mercruiser 5.7 TB EFI and we replaced the MAP sensor and spark plug wires and it ran fine today. The ECM is very expensive and from what I understand is very strong and should no be replaced unless you sure that it is not working correctly. A very trickey thing to play with.
 
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1BIGALF said:
My boat would not stop but would go a reduced speed and the alarm would go off. I do not have limp mode on my engine My ECM is a MEF1 I just had work done on my 1997 Mercruiser 5.7 TB EFI and we replaced the MAP sensor and spark plug wires and it ran fine today. The ECM is very expensive and from what I understand is very strong and should no be replaced unless you sure that it is not working correctly. A very trickey thing to play with.
Click to expand...

You have a better chance of getting a useful answer if you start your own new thread.
"Back up" to
Forum Home: Mercruiser Sterndrive Forum

and use Post New Thread button on left.
 
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I already do have a thread. I was just putting in my 2 cents on what I had and what I did to attack my problem. Try everything else before you change the ECM unless your sure it doesn't work.
 
ECMs are expensive but are not tricky to "play with". Just use the same simple precautions that you would when working on any electronic device and you'll be fine. Using standard precautions, the ECM is pretty much plug and play.
Since the op has used Mercrusier's service bulletin and identified that he has a faulty ECM then, it seems, that it is time for a new one.

My suggestion to the op is to do a search for a company that will repair his existing ECM. Or possibly find a used or reconditioned one.

Also, I'm curcurious what ramifications simply leaving the jumper wire in place might have?
 
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