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-   -   7.4 mpi no spark (https://www.offshoreonly.com/forums/general-q/376680-7-4-mpi-no-spark.html)

AllDodge 08-10-2022 04:03 PM

The motor came from the Merc with MR43T , that's years before iridium and platinum came around

SB 08-10-2022 04:07 PM


Originally Posted by Batmeat (Post 4841119)
if he’s running copper plugs and not something like platinum or iridium the spark will be super weak ( comparitively speaking) won’t get full combustion and foul the plugs.

just trying to look at every potential issue

That’s incorrect but a subject for a different thread i guess.

Batmeat 08-10-2022 04:30 PM


Originally Posted by SB (Post 4841122)
That’s incorrect but a subject for a different thread i guess.

man, I’ve been wrong for many years then. I’ll start a new thread about it within the next week. I don’t trust the internet, I’m sure you’ll find people who swear by either direction.

DrFeelgood 08-10-2022 05:23 PM


Originally Posted by Batmeat (Post 4841124)
man, I’ve been wrong for many years then. I’ll start a new thread about it within the next week. I don’t trust the internet, I’m sure you’ll find people who swear by either direction.

Copper is the best conductor. The advantage of the "exotic" materials is that the electrode doesn't get consumed as quickly as a copper one would.

Batmeat 08-10-2022 06:10 PM


Originally Posted by DrFeelgood (Post 4841135)
Copper is the best conductor. The advantage of the "exotic" materials is that the electrode doesn't get consumed as quickly as a copper one would.


well now I’m wondering if there is a gap issue with the plugs or if they’re side gapped to far. Unlikely, but worth exploring maybe.

CamaroMan 08-11-2022 10:24 AM

well - took whole dizzy apart, pickup coil looked fine.. it did pass ohms tests but i wanted to be sure..

going back today to do some peripheral tets - see if th eecu is firing injectors and an AC test on pickup output while cranking..

i dont want to say bad ecm but ya never know. I have to move my shop in 2 weeks and this couldnt come at a worse time.. need this job out the door

SB 08-11-2022 10:43 AM

A short - tach, wire or internal of coil, icm too much dwell, computer program too much dwell, or etc can cause coil to burn.

CamaroMan 08-11-2022 01:59 PM


Originally Posted by SB (Post 4841234)
A short - tach, wire or internal of coil, icm too much dwell, computer program too much dwell, or etc can cause coil to burn.

Fixed!! Ill be darned it was the white tach wire shorted to ground.. there ya go.. it was on the grey side before switching to white at the plug. There was a second spare gray wire that got pinched behind the harness plate.

Thankfully nothing damaged!



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