mercruiser 4.3 alpha-need ignition control module

[moefeeney]

alright.. I need help again, I am still getting no spark in my mercruiser 4.3 vortec after rebuilding the engine, I have since replaced the coil and ignition sensor, and still no spark. My next step is to, I guess, replace the ignition control module... which for the alpha model is around $500. I have been able to find the Bravo for much less but dont know if it will fit or if it will affect it. I guess my questions are.. will the bravo work.. and/or does anyone know where I can find a alpha ignition control module any cheaper... preferably asap... Thanks for your help

 

[Don S]

Re: mercruiser 4.3 alpha-need ignition control module

I am still getting no spark in my mercruiser 4.3 vortec after rebuilding the engine, I have since replaced the coil and ignition sensor, and still no spark.

Have you ever done any troubleshooting to find out if it was the module or something else. As you are finding out, replacing good parts with hopes of fixing the problem is expensive and doesn't usually work.
It would also help to know year and SN of your 4.3 Vortec.

No, the Bravo model won't work. Not designed to work with the shift interrupt system.

 

[moefeeney]

Re: mercruiser 4.3 alpha-need ignition control module

Ive tried troubleshooting it, I've followed the flow chart in the manual, I'm getting juice everywhere, but no spark coming from the coil to the distributor cap. I have also read in another discussion that someone say it may be the crank sensor? the guy I had rebuild the engine was a car mechanic, and hopefully he put the crank sensor together correctly, but I didn't think this would cause no spark... the year is 1999/2000 (the registration tells both years), with engine serial number 0L684510

 

[NHGuy]

Re: mercruiser 4.3 alpha-need ignition control module

The diagnostic path in the manual will lead you to the solution. If everything checked out there was probably a mistake made in the diagnostic work. Smart move is to retrace your steps...

 

[moefeeney]

Re: mercruiser 4.3 alpha-need ignition control module

the troubleshooting is leading me to the ICM... but it's just strange that it was working perfectly before the engine was taken out for a rebuild... I just tried replacing the shift interuptor switch, but that had no effect

 

[Don S]

Re: mercruiser 4.3 alpha-need ignition control module

Have you checked the coil wire?

 

[moefeeney]

Re: mercruiser 4.3 alpha-need ignition control module

i guess my question now is... anyone know where to get a cheap new or used ICM? I'm a broke chiropractic student looking to get this thimg up and running for the rest of summer... thanks!

 

[moefeeney]

Re: mercruiser 4.3 alpha-need ignition control module

what about the coil wire should i check?

 

[Fun Times]

Re: mercruiser 4.3 alpha-need ignition control module

Have you unhooked the gray wire off the negative side of the coil going to the tachometer and tried to start the engine?

Have you ensured you have a good ground at ignition control module area / wire.

Have you pushed and wiggled wires around? It kind of sounds like maybe a wire has backed out of a plug somewhere while reinstalling the engine hardware.

Good luck with it.

 

[moefeeney]

Re: mercruiser 4.3 alpha-need ignition control module

Ive tried the grey wire off, still no luck, I've pushed and pulled and wiggled every wire I can find... there is one black, flat ended wire by the distributor, near the carb that I havent figured out where it goes.. I've looked at all of the wiring diagrams and still nothing.. the same goes for a purple and white wire which I think that is supposed to be empty... other than that everything connected

 

[pwpns]

Re: mercruiser 4.3 alpha-need ignition control module

moefeeny if the ICM you need is part number 861251T1 marinepowerservice has them listed on e-bay for 399.00 + 10 s&h just type in the part number in e-bay search and that should bring it up. But before I bought it I would check grounds be sure they are clean and wiring connections are tight and clean use some electrical parts cleaner to clean any connections that might have got grease or dirt in them while disassembled. The pur/wh is for setting base mode timing

 

[moefeeney]

Re: mercruiser 4.3 alpha-need ignition control module

Ended up being the ground wire... or what I thought was supposed to be hooked up, is just an extra wire.. and when hooked up to the negative side of the coil, it grounds out the whole thunderbolt ignition system, took it off and fired right up