Possible ECM replacement

I have a 2000 Stingray 23 foot 230lx. It has 245 hours on the boat and has always been dry stored. I have a 350mag MPI engine. 2 weeks ago after about 1 hour of pulling kids on the tube the boat died in nuetral and would not restart. Towed it back in and next day it would not turn over until I pulled a plug then it would fire and start. It would start for a minute then sputter and die. This went on for about 6 tries then would not fire again. Took it home replaced igintion coil and got it to start then die. After a couple of hours of checking wires, I took off the gas cap and it would start and run. Then the engine would not go into gear. Gave up took it to the shop. Shop fixed gear shift said it was off the tracks and tried to replace the fuel pump relays to fix my main problem. He hooked the computer to read and it would not read at first messed with the ECM and got it to read. After replacements of the relays he ran it for 40 minutes and ran great. Getting ready for the weekend would not start at home. The mechanic said it must be the ECM. The ECM is $1800.00 and can not be returned if this is not the issue. Can anyone give any insight if they agree with this recommendation?

Re: Possible ECM replacement

You didn't go into much detail about how the tech diagnosed the problem to be the ECM, but ECM's fail very infrequently. Replacing the ECM is going to be an expensive project. It's not like you can just pop in a new one, the MEFI3 ECM that you have is NLA, you will have to update your engine wire harness for the new MEFI4 ECM. You better be sure about the diagnosis. <br /><br />More details about how the diagnosis was made would be good (if possible).<br /><br />Dave

Re: Possible ECM replacement

Thank goodness Dave stepped up.<br />I agree about ECM rarely failing.<br />When a mechanic says "uh must be the<br />ECM" I shudder.<br />Did the mechanic do a flow chart factory<br />test or did he just guess.

Re: Possible ECM replacement

To be sure about anything on that engine, a Merc serial number for your engine is MANDITORY, they don't even go by years anymore.

Re: Possible ECM replacement

He did several tests including<br />Overriding the igintion system and kill switch<br />Hooked up the computer to a Mercruiser Diagonistic reader<br />Followed the Mercruiser Flow chart of possible probelms and Mercruiser told him it must be the ECM<br />Conferred with another Mercruiser dealer and they both have agreed.<br />Talked to the tech last night and he could not give me 100% that this is the problem, but he said he was as sure as he could be for any electrical problem.<br /><br />Any thoughts???

Re: Possible ECM replacement

I think its well worth paying to find out what the current NO start problem is before going doing anything else<br /><br /><br />I just paid to have one of my cars checked to find out a brand NEW wire was just bad enough to cause a misfire the good part is my BIL runs the shop so its cheep<br /><br />tommays

Re: Possible ECM replacement

Ok, I would feel resonably good about it if they followed the Mercruiser troubleshooting charts, Mercruiser tech support was consulted, and another dealer also agreed with the diagnosis. Looking forward to hearing the outcome.<br /><br />Dave