Another Thunderbolt Ignition Problem

[buffdhc5]

Hello, hope you all can help,

I have a 2007 Mercury 220M 5.0L, S/N 0W665765, installed in a 2007 Bayliner 215 BR. Approx 45 hours on the engine and boat since new.

I had no problems with the boat since I purchased it from the original owner two months and 10 hrs ago. The last trip out the engine lost power and stopped in the middle of the lake. Had to get towed into shore. No spark. Inspected the distributor, it had corroded contacts so I replaced the cap and rotor. Still not spark. Replaced the sensor in the distributor, no change. Also replaced the coil with no change.

I have used the Thunderbolt V troubleshooting chart and have several questions.

1. I have checked the tach Gray wire and found 3.5 ohms of resistance at the tach. Disconnect the engine wiring harness at the engine the problem goes away (not a boat wiring problem). Reconnect the harness the problem reappears. Disconnect the negative wire from the ignition coil the problem goes way (both new and old coils). Does this count as a short, by definition its high resistance not a short? (FYI when I open the kill switch the 3.5 ohms goes away with all wires connected)

2. I do not have 12 volts at the positive terminal of the coil, I get 9-10 volts unless I disconnect the wire from the coil then battery voltage, 12 volts. (both new and old coils).

3. Checking the voltage from the module I also get 9-10 volts unless the coil is disconnected then its battery, 12 volts.

4. I have done the "tap" test with no spark produced.

It sure seems to me that I have to spend the $400 for a module based on the chart but the questions above make me question purchasing it. Any help would be greatly appreciated.

Thanks

 

[Reel Poor]

Re: Another Thunderbolt Ignition Problem

Did you disconnect the grey wire (tach lead) from the coil - then check for spark?

 

[buffdhc5]

Re: Another Thunderbolt Ignition Problem

I have removed the gray with white stripe wire, which is the negative wire and still not spark. Unless I'm missing something that is the only wire besides the power wire going to the coil, correct?

One thing I have done is clip a jumper to the ground post of the coil (with the gray wire still attached) and strike it against ground. I do get a small spark coming from the jumper wire when I strike ground.

 

[Reel Poor]

Re: Another Thunderbolt Ignition Problem

One thing I have done is clip a jumper to the ground post of the coil (with the gray wire still attached) and strike it against ground. I do get a small spark coming from the jumper wire when I strike ground.

Your engine is fuel injected with an Alpha drive? Don't be making sparks and jumping electrical componants, you can cause serious damage.

Also check the kill switch lanyard and the shift interupter switch.

 

[achris]

Re: Another Thunderbolt Ignition Problem

I have removed the gray with white stripe wire, which is the negative wire and still not spark. Unless I'm missing something that is the only wire besides the power wire going to the coil, correct?

One thing I have done is clip a jumper to the ground post of the coil (with the gray wire still attached) and strike it against ground. I do get a small spark coming from the jumper wire when I strike ground.

I have a circuit diagram for your engine, based on you saying "Thunderbolt V", and there is no gray with white stripe....

You need to remove the wire that goes to the tacho, and ONLY the wire that goes to the tacho... If you can't, then disconnect the gray off the back of the tacho, then isolate the other end from everything else and check for path to ground...

Chris......

EDIT: I have just been looking at circuits for another engine, MPI circuits, and lo and behold... I see Grey/White wire.... Now, is your engine carburetor or MPI???? If it's MPI you can not use a Thunderbolt V troubleshooting chart on it... :facepalm:

 

[buffdhc5]

Re: Another Thunderbolt Ignition Problem

Thanks for the feedback.

The engine is carbureted with an Alpha drive (I assume I'm using the correct troubleshooting chart). The gray and white wire that I have referenced is on the ground post of the coil. The tach wire at the tach is gray, it is the same color to the canonplug on the engine. I don't know if the color holds true on the engine side of the same canonplug. I have not cut open the wire bundle to see what color pin "M" turns into on the engine side. The only thing I know is when I disconnect the canonplug or the ground wire to the coil, the resistance on the gray tach wire goes from 3.5 ohms to open. Disconnecting the ignition module does not have any affect to the resistance.

I have disconnected only the gray wire at the tach for my "ground" check. That is when I found the 3.5 ohms. The resistance goes to infinity when I disconnect the wire on both ends, at the tach and engine canonplug (which was part of my troubleshooting to see if there was a problem in the boat wiring harness). I guess the question I have is, with the engine canonplug connected, the tach wire removed from the tach and the multimeter connected to the tach wire and ground, is 3.5 ohms a normal reading?

Thank you again for your input. I will keep checking all your ideas.

 

[buffdhc5]

Re: Another Thunderbolt Ignition Problem

Your engine is fuel injected with an Alpha drive? Don't be making sparks and jumping electrical componants, you can cause serious damage.

Also check the kill switch lanyard and the shift interupter switch.

I have check the shift interrupter switch at the engine and its good.

The kill switch is also working as advertised. The only thing that makes me question it is it affects my ohm reading on the tach wire. When in the "run" position the reading is 3.5 ohms but when I turn the switch "off" the resistance open.

The spark and jump test is an "old school" way of checking a coil. Actually still taught. http://www.youtube.com/watch?v=xVhk5FZjyzc

 

[Don S]

Re: Another Thunderbolt Ignition Problem

The minus terminal on the coil is NOT a ground.
Disconnect the gray wire from the tack, not at the coil, and see if you get spark.

Like Chris, I find nothing about a gray/white wire on any diagram. Can you trace it and see what it goes to? May not even be OEM
Here is the wiring diagram/s I have for your engine. Use the 02 TKS diagram.

View attachment 2-2R.pdf

 

[buffdhc5]

Re: Another Thunderbolt Ignition Problem

Thanks guys. I will take a look tonight and report back.

 

[buffdhc5]

Re: Another Thunderbolt Ignition Problem

Ok, disconnected the gray wire at the tach, no spark.

Disconnected and checked the ignition switch, its good.

Disconnected and checked the kill switch, its good.

I have check every wire (engine related), both boat and engine, for continuity, they all pass per the diagrams.

The wire to the negative side of the coil is indeed gray with white stripe however the wire traces as per the diagrams you gave me Don. The canonplug has letters next to the pins instead of numbers like the diagrams. It all looks factory however with the original black sealant paint on the connections. (one correction the engine was installed in a 2007 boat but was manufactured in 2006)

While I was going through the troubleshooting flow chart again tonight I touched the ignition module, wow it was hot. My guess is that's not normal. I let it cool and turned on the the ignition switch to the "run" position, the module was hot in about 15 seconds. Sure looks like I have to the replace the module.

Unless you all have some other ideas I will track down one of the modules and install it.

Thanks again for the very valuable and professional help.

 

[buffdhc5]

Re: Another Thunderbolt Ignition Problem

I know it's been almost a year but I wanted to close out this issue. I did replace the electronic ignition module with a new unit. This solved my problem. I ran the boat for the rest of the summer with no problems at all.

Thanks to all who helped me troubleshoot and fix the problem.