Bad ignition module - 5.7 Thunderbolt V

[AShipShow]

Hey all,

I'm finishing up a 3yr restoration of my 96 bayliner... I started up the engine on muffs a couple weeks ago to check my throttle/carb settings and everything was working great.

Just the other day, I went to start it up again to check a few more things and it would not start for anything... after all the basic checks, i determined i wasnt getting spark. I then just automatically assumed bad coil... (just kidding :lol
I grabbed my mercruiser manual and went thru the thunderbolt ignition troubleshooting flow chart... basically ended up at bad ignition module... :facepalm:

Before shelling out 600 bucks (more than I paid for my boat), is there anything else worth checking... is my new module also going to try?
not sure what did it in and I'm nervous the new one might have the same fate...

Also, not sure, but it looks like you cant even buy the module I have anymore... it appears you have to buy a new style module and a conversion kit.

My engine serial number is 0F769374... thunderbolt V without knock sensor...

Thanks for any help and sorry if there's any typos, I'm on my phone

 

[alldodge]

So you either have 0V on the Wht/Red coming from the Ignition module, or your striking the Wht/Grn wire with the Wht/Red connected and your not getting spark, correct?

 

[AShipShow]

Edit: see next post...

 

[AShipShow]

So you either have 0V on the Wht/Red coming from the Ignition module, or your striking the Wht/Grn wire with the Wht/Red connected and your not getting spark, correct?

I have 12v at the wht/red wire with the key on but no spark when striking the wht/grn wire... tried swapping a coil with no change.

 

[alldodge]

Yep, sounds like ICM

Maybe time for EST

 

[AShipShow]

Yep, sounds like ICM

Maybe time for EST

Do you have any more info on the delco est stuff? Not sure which kit I would need... do they make a adapter for the plugs, or do you need to cut the old plugs off and wire the new ones in?

 

[alldodge]

Just search delco est and find the V8 and your good

The kit comes with new wires. This was just the first one which came up, so look around
Iboats sells Sierra kits

https://bpi.ebasicpower.com/shop/al...co-est-marine-v8-gm-305-350-454-502-edm550002

 

[AShipShow]

Ok, yea, seems like one kit covers almost anything.... ended up going with this one... best price I could find, sorry Iboats

Thanks for your help alldodge

 

[Scott06]

May be too late but I’ve gotten two ignition modules used on eBay for about $200 when I swapped out my 4.3 for a 5.0

 

[tank1949]

Hey all,

I'm finishing up a 3yr restoration of my 96 bayliner... I started up the engine on muffs a couple weeks ago to check my throttle/carb settings and everything was working great.

Just the other day, I went to start it up again to check a few more things and it would not start for anything... after all the basic checks, i determined i wasnt getting spark. I then just automatically assumed bad coil... (just kidding :lol
I grabbed my mercruiser manual and went thru the thunderbolt ignition troubleshooting flow chart... basically ended up at bad ignition module... :facepalm:

Before shelling out 600 bucks (more than I paid for my boat), is there anything else worth checking... is my new module also going to try?
not sure what did it in and I'm nervous the new one might have the same fate...

Also, not sure, but it looks like you cant even buy the module I have anymore... it appears you have to buy a new style module and a conversion kit.

My engine serial number is 0F769374... thunderbolt V without knock sensor...

Thanks for any help and sorry if there's any typos, I'm on my phone

I read your post and have concerns for my own rebuild. Three years ago, it ran fine. However, it has set a long time while I performed other repairs. I don't want to be caught having the same future issues as you. I did a web search on "Mercruiser TBV ICM" and Amazon came up with these. I am not sure if TB IV and V are the same. It was my understanding that TB V is a bit smaller than IV and has the option for a knock sensor. Mine has sensor. Anyway... these seem reasonably prices! I'm learning too! https://www.amazon.com/mercruiser-ignition-module/s?k=mercruiser+ignition+module

 

[Rick Stephens]

When that happened to me I just replaced with EST. I like it.

 

[AShipShow]

I read your post and have concerns for my own rebuild. Three years ago, it ran fine. However, it has set a long time while I performed other repairs. I don't want to be caught having the same future issues as you. I did a web search on "Mercruiser TBV ICM" and Amazon came up with these. I am not sure if TB IV and V are the same. It was my understanding that TB V is a bit smaller than IV and has the option for a knock sensor. Mine has sensor. Anyway... these seem reasonably prices! I'm learning too! https://www.amazon.com/mercruiser-ignition-module/s?k=mercruiser+ignition+module

Those are not the correct modules.. those are replacement modules for the new ignition system I will be switching to... looks like EST is the way to go... cant believe how expensive a replacement merc module is...

 

[AShipShow]

May be too late but I’ve gotten two ignition modules used on eBay for about $200 when I swapped out my 4.3 for a 5.0

Thought about it, but a used module seems like too much of a risk for me

 

[tank1949]

Thought about it, but a used module seems like too much of a risk for me

Usually Amazon and Ebay offer free returns within 30 days. I would not buy one with out that offer. Good luck!

 

[AShipShow]

Welp, I installed my new EST ignition this evening, and it went pretty smoothly, however something is throwing me off....

When I removed the old distributor, i cranked the engine so the rotor was pointing just about perfectly toward the carburetor (straight forward) and I even made a little scratch mark on the intake manifold... I popped out the old one and aligned the new one to the same location...

I got everything installed and went to start it up on muffs just to see where my timing was assuming I would need some adjustment to get it running smooth enough to let it get up to operating temp... The timing mark was not showing up at all under the timing light even tho the motor started right up and was running pretty smooth...

I stopped the motor and felt around the harmonic balander and found the slot and took a silver sharpie and filled it in to make it easier to see...

Started the motor back up and still couldn't see it, so I started looking around in each direction and I found it... it was lighting up super consistantly at like 110-120° BTDC... Clearly this can't be correct....

I double checked and I had the timing light clipped on the #1 cylinder plug wire... Its a dumb timing light, so no advance or anything...

WTF is going on?? the only thing I can think of is my harmonic balancer failed and my timing mark is way off
Any other thoughts??

 

[Rick Stephens]

Me thinks you must be right. Only thing I can think to do at this point is pull the valve cover and spark plug off #1 side and crank t to TDC.

 

[alldodge]

Also agree, but in most cases I've have not seen then go that far off.

Number 1 is port side front, right

 

[tank1949]

Water over damn now, but you should have marked everything before u pulled dist. Now, do what Rick says. Do not manually turn over motor using harmonic balancer's main bolt. If it snaps off, ur in deep sh----!

 

[AShipShow]

K, so I pulled the front pulley off the balancer this morning and it looks like the timing notch is about where it should be relative to the keyway (per what I've seen on the ever-reliable internet)... Appears to be a couple degrees ATDC relative to the keyway... So I'm not going to pull the harmonic balancer because its clearly not like 100° off which the timing light was showing...

Now I'm lost... I might go buy another timing light, but I can't imagine it was off or glitchy because it was extremely repeatable when it was firing on the timing mark... The timing mark was not even moving under the strobe, it was dead still...

 

[AShipShow]

Good news... it was a full blown ID10T error... apparently the timing light clamp has an arrow on it that has to point towards the spark plug... apparently if its pointing the other way, it's about 100 degrees early lol...

Probably the best case scenario tho ..