No spark 2003 Mercruiser 5.7 with thunderbolt style ignition

[JaCrispy]

Sounds like a ground issue or bad connection and the coil is getting ground through the test light itself.

 

[Karen S]

Another update: We bypassed the kill switch and neutral safety switch, and it is the same. We get a flash once in a while on the timing light but not continuous. It will not start. When we hook the test light on the 12 volt power supply to the negative on the coil and energize coil, it will start and run. Could it be the ECM? Thank you!

 

[Karen S]

We do have a tach but it has never worked since we bought the boat in June 2014. Sorry about that, I said that we don't have one.

 

[NHGuy]

What about following that ground to it's source?
Or clean the electrical connections in the,master plug. I did mine with emery cloth. Disconnected the battery, emery'd the male plug ends, stuck a razor blade in the splits in the male plug ends to open them a bit. Rolled up some emery with the abrasive out to do the female ends of the plugs. In hindsight it would have been smarter to find tiny metal brushes. The rolled emery cloth was a PITA. I had been having some electrical gremlins til then. After, none.

 

[Karen S]

Thank you! We will try cleaning that tomorrow. Hoping that will work. Thank you again!

 

[Karen S]

We cleaned it really good, used a really small gun cleaning brush and it still will not start and run. We thought that would be the problem but it wasn't. I am going to take it to a marina Tuesday and see if they can fix it unless anyone has any other ideas? Thank you so much everyone for your help. Really appreciate it!

 

[Fun Times]

You've tried 2 sensors under the distributor cap now? Try doing an ohms check to the sensors like seen on page 4B-21, http://www.boatinfo.no/lib/mercruiser/manuals/mercruiser24.html#/306

Here's your distributor circuit, http://www.boatinfo.no/lib/mercruiser/manuals/mercruiser24.html#/646 and the following link is a must read plus be sure to get up to page 5G-43 in order to do tests 4, 24, 26+, http://www.boatinfo.no/lib/mercruiser/manuals/mercruiser24.html#/666

Again try removing the gray wire off of the back of the tachometer....you need to be sure it's not your problem. And when you get the engine running, repair the tachometer or get a new one...you need it working to run your boat properly.

If you believe to find the problem to be a defective ECM, try calling OBD Diagnostics to see if he can test your ECM. You have the MEFI 3 ECM. http://mefiburn.com/contact.asp

Good luck.

 

[Karen S]

Yes, we have tried 2 sensors. We printed all the pages and will do all the tests tomorrow. Thank you again! Maybe there is hope!

 

[Karen S]

While we were looking at the diagram, it appears that the ECM works in conjunction with the IC module. Could it be possible that the IC module is defective? Is that common? We will unhook the tach tomorrow and do the other testing too. We really appreciate the help. Thank you!

 

[Fun Times]

While we were looking at the diagram, it appears that the ECM works in conjunction with the IC module. Could it be possible that the IC module is defective? Is that common? We will unhook the tach tomorrow and do the other testing too. We really appreciate the help. Thank you!

Since you have the two wire ignition sensor under the distributor cap and not the ignition control module under the cap, your model doesn't utilize the IC module for timing, etc. The timing is done within the ECM and not the IC (ignition control module) Module. Page 5G-39 describes the process.

 

[Karen S]

UPDATE: Thank you so much Fun Times! We unhooked the gauges, have to unhook all of them and that boat started right up! We thought it was so much more complicated than that. I can't believe the time we have spent on that boat just to find out it is so simple! I am so happy! Next question, is it fixable or do we get a new one and where would we get another one? I can't thank all of you enough for all your help! We called mercury, a marina mechanic, and a marine store mechanic. Not one of them told us to check that. Thank you so much! We appreciate it more than you will ever know. :joyous::joyous::joyous::joyous::joyous::becky::becky::becky::becky::becky::usa2::usa2::usa2::usa2::usa2:

 

[Karen S]

The boat is a 2002 Regal Commodore 2665.

 

[Fun Times]

Good to hear Karen S, glad it was something so easy....Think of it this way, at least you now know how to diagnose your engine a whole lot better when something else goes wrong on the electrical side of things.

Depending on the model tach gauge you have, about the only thing you can do that sometimes works when the gauge doesn't show an RPM is turn the arrowed dial on the back of the gauge a few times and put it back to the number of cylinders of the engine....That mentioned, I don't believe that trick will work on yours now because since the tack kept the engine from running, it's internally shorted out and the only safe way to repair it is either send it in to the gauge manufacture for service as some manufactures offer a repair service when possible or try to find a new gauge as close to matching what you have now.

Are there any part numbers along with the brand name on the front or back of the gauge? what color is it? Have any photos of it you can post?

 

[Karen S]

I think I will have to contact Regal. They say Regal on the front. It is an integrated circuit board with all the gauges in one unit. I tried to post a picture of ours but they are too big and won't download here. This picture is from a for sale site. Thank you again!

 

[Karen S]

I got it but it is upside down.

 

[Fun Times]

I think I will have to contact Regal

^ Thanks!!!

Contacting Regal would be one of your best options to start with as that instrument panel design would be pretty difficult to try and service without professional help. If Regal can't seem to help then you might try doing an online search of instrument panel cluster repair to see if any of them can repair yours.

Be sure to let us know what they say all your options are. Good luck.

 

[Karen S]

I called Regal and they gave me the place to contact to get another one. I love Regal, lifetime guarantee! I was thinking it would be expensive but no worries! I already replaced enough parts. Thank you again for all your help! You have helped more than you can imagine!