HEI module
 

Is there a way to test these to see if it`s good or bad ?

https://www.westmarine.com/sierra-18...yABEgJDrPD_BwE

Most auto parts stores have a tester. I don't know how accurate they are, but I have had a few tested over the years and none of them ever failed the test. It always led to more troubleshooting and in every case I found the problem elsewhere.

the problem is the pick up coil pull the dist gear off slide the shaft out and change the pick up coil most auto stores have it ,use thermo paste under the module i,m changing one right now with no spark

I normally test the modules using a spare to confirm it's dead. I've had a few fail on me over the years.

The engines are doing weird stuff.
We can`t figure it out .
Everything works fine till it doesnt .
One day out of nowhere neither engine would start .. no tach signal.
drive it home , starts back up.
Same tune in both engines , one will be fine the other will drop duty cycle like a clock and only in gear .

Eddie Young says get rid of the daytona boxes they are not needed and cause RF interference.. maybe thats it.

Unfortunately I don`t know Mefi and how to rewire it so .. good times

Most likely not your issue but mine had this mess that a big time shop missed while diagnosing why it would not run... and "foul plugs" total garbage but that's a long story.

The tiny little relay on the right and the dist. block runs 2 of my 4 fuel pumps, looks pretty trustworthy eh?. All been replaced/ cleaned now.
Since you have nothing else better to do :angry-smiley-055: it may be worth checking out if nothing else but to clean. I had to dig under some covers to find these.

https://cimg1.ibsrv.net/gimg/www.off...2ef538309a.jpg
https://cimg3.ibsrv.net/gimg/www.off...32341ed89b.jpg
https://cimg6.ibsrv.net/gimg/www.off...b7ca8a330a.jpg

I see a lot of tinkering this winter!!!

its not a relay,,its a circuit breaker.but yeah,you had some corrosion.

you run holley efi,right.is there a place for inputting dwell?
short story,I got a tune for a starting point on mefi4b,,little did I know,the tuner had jacked up the dwell 2-3 x more than a stock merc.I'd be going along and the engine would just die.finally stumbled upon that one,,never blew another module.did get good at replacing them while boat was under way.

That’s a great point.
Many car tuners have run into the ignition dwell issue too. Maybe because many didn’t understand it.

Fun fact - Carb’d motors I used to literally bypass the module when using the crane box with the gm est dist , i just used the dist as a magnetic pick up distributor.

What was ignition dwell at? Ive seen as high as 15 MS in stock, virgin tunes. Ive lowered them under 5 and engine still ran fine. At 15, the module overheated around 5800 to 6200 on dyno then acted like a rev limiter fwiw, smitty

Hmmm I`ll have to check the tune for that

.. I could not replace the module . The rear 2 pins must be soldered? I cold not get them off.

that sounds modified at 15,,all the stock merc tunes I had were in the 3-6/7,,mine were 12-15,,it would cook the module,,merc has a big round rotor w/ fan blades on the bottom,,that helped some.

I thought it was a plug but it`s soldered together

https://www.summitracing.com/parts/m...CABEgIK7vD_BwE

stock 502 mags are 15.38 MS all the way acrossed the board
stock 500 efi is 10.00 MS all the way acrossed the board
Ive actually never seen any stock mercuiser tune thats not 10 or higher.

I just put a new battery in my toughbook,,guess I'll open up a few files and look.won't be the first time I forgot the numbers.
also,I wonder if theres a translation difference betw mefiburn and actual merc tuning software.

My bad...the relay was just out of view. Similar condition also replaced.

I got em both started .. port needed the tune reloaded.. seems like RF or something is corrupting the files . Im getting both new distributers,, Eddie young says they give him lots of issues.

Dan, the CD-1 ign boxes are the RF issue or the plug wires transmitting?

What type of shielding does the EFI computer have?