01 Mercruiser 5.0 with no power to fuel pump and no spark??

[kennymc]

I have a 01 Rinker Flotilla with the 5.0 Mercruiser in it I've been working on the last couple months. Had the engine out, outdrive off and torn apart, gimble housing off, just completely torn down replacing corroded parts. Finally have it all back together and was running on the hose just perfect. Shut the boat off and headed to the launch for a test run only to get there and it not crank. Now I've spent the last 2 days chasing my tail trying to figure out what's going on. I have no power to my fuel pump and no spark. When I turn the key on all I hear is the relay on the engine click, Fuel pump doesn't prime or nothing. I jumped the pump with 12 volts and it runs fine so I know its not that. I've swapped both relays on top of the motor with my buddy's from his boat and nothing, decided to dump a little fuel in the throttle body and see if it would fire off and once again nothing. Pulled a spark plug and had the wife spin it over and there's no spark. I've check every fuse I could find on the boat, I do have 12 volts at my coil and when I flip my kill switch up and down I can here the relay working on the motor so I know its working. I read somewhere that a bad tach will cause a motor no to crank, first ive ever heard that, my tach doesn't work but it was running fine before so I really don't think that's an issue. I don't know what else to do, what would cause it to loose power to the fuel pump and no spark at the same time when before it was running great???? Please help....

Thanks

 

[achris]

Do you have an engine serial number? As the Mercruiser 5 litre is available to boat builders in many variants, we need to know which one your boat builder bought...

 

[Fun Times]

As Chris mentions above, we need to know what engine model you have and the serial number takes the guess work out of finding the best available information for us to help you better... But for now it seems you have an EFI engine....If so, Have you checked for a loose/bad wire connection at the grounding stud at the rear of the engine. The engine & ECM wiring harness has it's own ground wire near/at the flywheel housing. Also try wiggling the main 10 pin wire harness cannon plug while the key is in the ignition on position to see if the fuel pump powers up.

Do all the gauges seem to power up at key on no crank position? 12v gauge says?

Something is not telling the ECM to power up for 2 seconds at key up and the ECM is not reading an RPM signal while cranking over which means no spark.

Since you just had everything apart and you disturbed the wiring harnesses, start checking for backed out wiring pins at all the connectors including the ECM connectors and the wires at the distributor module mounted under the cap & the pickup coil under the rotor.

 

[kennymc]

My engine S/N is M041595, it is efi. I've checked all my harness connections, wiggled the main harness, and all the grounds seem to be tight. I pulled the key switch out and tried jump the connectors, still the same results.

As far as my gauges half of them don't work all I have is oil pressure, volts and fuel working. Tach doesn't work nor read the hours which is how it was before I ever started the project and like I said it was running fine on the hose before. I've found new panels with gauges just was waiting to get it in the water to make sure all was fine before I spent the 800 dollars to get them.

 

[kennymc]

Thanks for the info fellas, figured out today it is my ECM. A friend has the same motor in his and let me try it and it ran perfect again. Sad part is of course its discontinued and dealer wants 2700 for the conversion kit so if anyone knows where a good used one is please let me know....

 

[achris]

Interesting. Although you say the boat is 01, the engine (from the serial number) comes up as 1998....

Actually, the ECM IS still available, and new it's $1481... (me thinks your dealer might be leading you astray :noidea

Does it look like this?

 

[kennymc]

No, don't look like that. The merc parts catalog does show its a 98 motor, have no idea why but the ECM it shows for me is the correct looking one. Its P/N is 861925T 3. Heres a link to the page https://webapps.brunswick.com/literature/literaturePartsInfo.do , the conversion kit P/N is 892700A01

 

[kennymc]

Do you know of any places that rebuild them?

 

[Fun Times]

The engine is a Mercruiser 5.0L EFI bravo drive that uses a MEFI 3 ECM and a Mercruiser distributor sensor assembly....No pickup coil under the rotor like my guess above.

Do you know of any places that rebuild them?

For a possible rebuild call mefiburn and talk to them.http://mefiburn.com/contact.asp

You'll want to try and find out what part of the ECM failed and then depending on what they think failed, you may have to try and find out why that circuit failed by checking ohms and volts of the circuit in question to try and prevent it from happening again. Be careful using your friends ECM as should there be something wrong, it could also damage his or the new one. < It's rare but it's happened more than once.

Good luck.

 

[kennymc]

Thanks, I will have to look into it for sure. Does have the bravo 3 outdrive. I'm thinking I might of fried the computer myself, i was using one battery with not everything hooked up that was getting pretty weak from me working on the boat so long and the boat actually uses 2 batteries. Don't know if that would of caused it or not but It might have.

Thanks again for all the help, ive used this site lot but first time ive ever had to post on it.. Great site