6.2 MPI Cranks but won't start.

[alldodge]

http://www.marinemechanic.com/merc/d...i3-nostart.PDF

Hmmm this is interesting maybe there's still some hope in not replacing the ECM.

Not my engine serial numbers but the same ingniton sensor, I wonder...

It could very well be, but if we go back I was lead to believe the TB-V troubleshooting guide was used and only the coil was not sparking. If this is not the case I suggest running through it.

 

[Merc4ever]

It could very well be, but if we go back I was lead to believe the TB-V troubleshooting guide was used and only the coil was not sparking. If this is not the case I suggest running through it.

Hurray hurray! Yes you and the good folks at Mercury have set me straight! I needed to remove the white green wire and touch the other purple side that goes to the ECM to a good ground. A beautiful spark came from my tester that was plugged into the big HV coil wire and clamped onto a ground. All I need to do now is replace the (not working) ingnition sensor inside the distributor not the ECM. :joyous: Thanks a million for your patience and time, pal.

 

[Merc4ever]

I high fived too soon, I replaced my igniton sensor Mercruiser part 87-892150Q02 even though it had an extra black wire that wasn't on my original sensor (I put it to the engine ground stud) and the new one also looked differently with 2 less screws on top of it. I also found a old black wire connected to ground with a small ring lug laying near the distributor? Anyway it started right up and I thought we had the problem fixed.

I can't really make out the serial number but it certainly is a 2001 MX 6.2 MPI with the MEFI 3 ECM.

Out on the lake I found dangerous sparks emiting from under the coil side of the ignition wire to both the + and - side of the coil, and it's running very rough now. There's also a new problem of being very hard to start after running for a while. I tried a new coil and quicksilver ignition wire set part 84-816608Q83 but still the same problem. Could I have the wrong type of Ignition sensor? Will I explode now?

 

[alldodge]

I high fived too soon, I replaced my igniton sensor Mercruiser part 87-892150Q02 even though it had an extra black wire that wasn't on my original sensor (I put it to the engine ground stud) and the new one also looked differently with 2 less screws on top of it. I also found a old black wire connected to ground with a small ring lug laying near the distributor? Anyway it started right up and I thought we had the problem fixed.

I can't really make out the serial number but it certainly is a 2001 MX 6.2 MPI with the MEFI 3 ECM.

Out on the lake I found dangerous sparks emiting from under the coil side of the ignition wire to both the + and - side of the coil, and it's running very rough now. There's also a new problem of being very hard to start after running for a while. I tried a new coil and quicksilver ignition wire set part 84-816608Q83 but still the same problem. Could I have the wrong type of Ignition sensor? Will I explode now?

The sensor is correct but getting sparks coming from under the coil is not. The coil wire boot should fit over the coil post to keep any kind of spark from making it to the +/- posts. I don't see the sensor as the issue but the sparking should not be their. If everything is connected the way it should with the correct parts (wires, boots) then the sparking should not happen unless the coil is damaged. The sparking you have not is causing the engine to run ruff because it is not getting spark on all plugs. Don't continue to run it without figuring out the issue

 

[XiViperI]

I over-tightened the nuts on top of the coil in the past and had the same crazy spark issue. They are really soft, doesn't take much. Good luck..

 

[Merc4ever]

I checked the connections on the coil and they weren't too tight so I started checking wires because it ran good before all this work. I found one ignition wire might not have been seated all the way on and I put insulating electrical grease around all the posts and plugs (not the metal parts that are suppose to be conductive) and it ran good with no more sparks. Thanks again everyone! :joyous: