I have had a problem boat wih a Mercruiser 350 MAG MPI 5.7L engine with Bravo 1 outdrive.. It was a saltwater boat when i bought it, and over the last two years, I have slowly carved away at the problems.
Engine S/N: 0W619678
Replaced so far on the engine: Manifolds and Risers, Oil Pan & Gaskets, Water Pump, Long Block with a remanned long block, Gaskets and the full works, Transom Gimbal Assembly, IAC, Temp Sensors and Senders in 2022 and 2023. The boat engine was out this year because the reman long block had the piston rings reversed. Fixed that and have a great compression on all 8 cylinders. The engine runs great on a hose.. No issues.
The issue I am trying to resolve is the engine's cut-off at load once it's dropped in. It sputters, goes into guardian mode, and eventually cuts out. Sometimes, it just runs really rough, like it's choking for air.
We thought it was the fuel pump ( cool fuel 3 module) and the distributor, so we replaced both this year. The new cool fuel module was expensive !!!
I got a Diacom Cable from eBay and have been checking for codes. There are no major alarms except a few random things I would like some advice on.
1. As soon as you go into drive, the engine goes into guardian mode, runs rough and sometimes cuts off. The potential fix here maybe is a bad coil. I will replace this, but I am not sure if it is indeed the problem. Also, Is there an alternative brand/manufacturer for part number 863704T? The OEM part is 450$ WOAAHH?
The Diacom software offers a fuel injector test, which I have been using to diagnose the issue. However, I have encountered a challenge. While I can successfully fire the first four fuel injectors, the software indicates that it cannot run the test on 4-8 due to the part not being there. I suspect a faulty relay, but the diagram is unclear, and I am unsure if this is the expected behavior with the diacom software. I would appreciate any advise insights from some familiar with the software and fuel injectors.
3. Since we suspect our old block had some raw water intrusion, I think the fuel injectors may need cleaning or replacement. Is my rough running issue possibly due to the fuel injectors?
Engine S/N: 0W619678
Replaced so far on the engine: Manifolds and Risers, Oil Pan & Gaskets, Water Pump, Long Block with a remanned long block, Gaskets and the full works, Transom Gimbal Assembly, IAC, Temp Sensors and Senders in 2022 and 2023. The boat engine was out this year because the reman long block had the piston rings reversed. Fixed that and have a great compression on all 8 cylinders. The engine runs great on a hose.. No issues.
The issue I am trying to resolve is the engine's cut-off at load once it's dropped in. It sputters, goes into guardian mode, and eventually cuts out. Sometimes, it just runs really rough, like it's choking for air.
We thought it was the fuel pump ( cool fuel 3 module) and the distributor, so we replaced both this year. The new cool fuel module was expensive !!!
I got a Diacom Cable from eBay and have been checking for codes. There are no major alarms except a few random things I would like some advice on.
1. As soon as you go into drive, the engine goes into guardian mode, runs rough and sometimes cuts off. The potential fix here maybe is a bad coil. I will replace this, but I am not sure if it is indeed the problem. Also, Is there an alternative brand/manufacturer for part number 863704T? The OEM part is 450$ WOAAHH?
The Diacom software offers a fuel injector test, which I have been using to diagnose the issue. However, I have encountered a challenge. While I can successfully fire the first four fuel injectors, the software indicates that it cannot run the test on 4-8 due to the part not being there. I suspect a faulty relay, but the diagram is unclear, and I am unsure if this is the expected behavior with the diacom software. I would appreciate any advise insights from some familiar with the software and fuel injectors.
3. Since we suspect our old block had some raw water intrusion, I think the fuel injectors may need cleaning or replacement. Is my rough running issue possibly due to the fuel injectors?
