Trash

It would help to get everything at a baseline and go from there or we are chasing our tail. If the TPS looks good (voltage sweep smooth) and MAP ok then an injector cleaning and flow testing would be in order. Usually they begin to flow less but you may have an injector hanging open thus causing the rich condition. Get them baselined (cleaned and flow tested/balanced). Find out what size injector you have.

I don't think the MEFI unit is the problem unless someone installed a completely useless tune.

1 2 NV

Im to the point where I can have a harness built for my Holley HP ECU. Then I can use that rather than the mefi 1 ECU. I'd have total control plus datalogging and I would be able to at least monitor the sensors to figure out what is wrong if anything.

I'd still like to know if it's the tune on the ECU though.

I'll do another sweep on the TPS. When I originally did the first sweep it was good but I do remember one spot where I lost voltage. I couldn't get it to repeat that voltage loss through several follow up sweeps. If I remember correctly the map has to be swept while running. That isn't an very viable option as I can't run the boat out of water due to the pump needing water to lube the bearing seals.

Trash

How much are you spending on the harness for the Holley unit? How does that price compare to purchasing MEFI Burn? I'm not associated in any way shape or form but if you had the software you could download the tune and see the tables. I'd look at it for you if I was closer.

We also don't know what the AFR actually is other than 'black smoke and rich smell".

1 2 NV

I might have to steal my manifolds from my 383 as they already have a O2 sensor spacer in them.

Harness is about $400.

Trash

MEFI Burn is only a little bit more and you can see what's going on along with your in hand 383 manifolds / O2 sensor.