2008 mercruiser 5.7 MPI ignition coil test

[mercman12345]

Does anybody know how to do an ohms test on this coil? Its the new style coil, just like this one on ebay.

http://cgi.ebay.com/ebaymotors/Merc...9341111QQptZBoatQ5fPartsQ5fAccessoriesQ5fGear

The manual doesn't say how to test it. thanks in advance.

 

[mercman12345]

Re: 2008 mercruiser 5.7 MPI ignition coil test

Anybody here have a clue on this one?

 

[Don S]

Re: 2008 mercruiser 5.7 MPI ignition coil test

Do you have a Merc serial number for your engine? Nothing listed by year.

 

[mercman12345]

Re: 2008 mercruiser 5.7 MPI ignition coil test

Sure its ow372421
Thanks.

 

[Don S]

Re: 2008 mercruiser 5.7 MPI ignition coil test

There are no OHM's tests for that coil, what exactly is your problem, and what manual are you looking at?

 

[mercman12345]

Re: 2008 mercruiser 5.7 MPI ignition coil test

Problem is, is that after running a while the engine dies. I do a spark test with a spark board and it shows no spark. Let it sit for an hour, spark comes back. Then it's wash, rinse, repeat. So i'm thinking its the coil (i've worked on older musclecars for a while, but this is new to me).

So I order service manual 31 thinking it will tell me how to test the coil to confirm its bad, and they show a picture of it, but no tests for it in the manual.
How in the world am I supposed to confirm the coil is bad? It's a $300 part so i'm not just going to swap it. What makes this one so special? I'm assuming it's not gold inside

 

[Don S]

Re: 2008 mercruiser 5.7 MPI ignition coil test

Have you checked all the other items like the Main Power relay, done a scan with a diagnostic computer and the other tests in the manual for no spark?

 

[Pete104]

Re: 2008 mercruiser 5.7 MPI ignition coil test

Have you isolated the problem to the engine by eliminating the dashboard?

 

[mercman12345]

Re: 2008 mercruiser 5.7 MPI ignition coil test

Don,
I don't think its the relay as the fuel pumps fire up, and the problem comes and goes with the amount of time the engine runs almost like clockwork. About 1/2 hour of running is all I get and then it quits with no spark.
I don't see a section in the manual to troubleshoot no spark other than the thunderbolt ignition system chart thats in the manual, which is not my coil.

Do I have the wrong manual here? Does the scan tool test the coil somehow? Have you ever troubleshot this coil before? I'm just asking becuase it sounds like Pete104 has no clue by asking me to isolate the dashboard.

 

[Don S]

Re: 2008 mercruiser 5.7 MPI ignition coil test

You have to follow the procedures in the manual. There are no specific "troubleshoot the coil" procedures. You troubleshoot around it.
If you follow the troubleshooting charts for no spark, you will find out what the problem is. But you have to do the tests.
Yes, you have the right manual.

 

[mercman12345]

Re: 2008 mercruiser 5.7 MPI ignition coil test

Don, I appreciate your help. But i'm still a bit lost on this. The best I can find in the manual is how to troubleshoot the thunderbolt ignition system, not this one. Is there a page or a section i'm missing here. Or if you have the manual to, a suggestion on what page to start from?
Thanks.

 

[Don S]

Re: 2008 mercruiser 5.7 MPI ignition coil test

Duh, you have manual 31 not 36 for the 555 ECM,
Download it for free, here. http://www.4shared.com/document/FWwx1Vs7/Service_Manual_36_Rev_1_SBC.html
Glad you said the manual talks about the Thunderbolt ignition, 36 doesn't even mention it.

 

[mercman12345]

Re: 2008 mercruiser 5.7 MPI ignition coil test

I just gave it a read. First off many thanks!
From the quick scan I gave it, it looks like I have to test the coil through a scan tool of some sort. Does that sound about right?

 

[Don S]

Re: 2008 mercruiser 5.7 MPI ignition coil test

The scan tool is one of the tools you are going to need, and don't forget to check the basics.

 

[mercman12345]

Re: 2008 mercruiser 5.7 MPI ignition coil test

I just wanted to say thanks very much for the manual and for the help Don!

 

[Pete104]

Re: 2008 mercruiser 5.7 MPI ignition coil test

I certainly wasn't trying to mislead you. My habit is "to isolate the engine from the boat".