Need some help 496 mag running rough.
#1
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Need some help 496 mag running rough.
Hey everyone I got this motor scratching my head big time. It sat in a crate for a few years before I got it and put it in the boat. When I first got it, it ran terrible. Cleaned 7 injectors and had to replace one. After that I took it out and it ran flawlessly. Didn't miss a beat once. One day I was running and hit a boat wake and I'm guess my belt tensioner had slipped so it slung the belt off. I didn't realize it until the water pressure alarm went off and temperature spiked. After I got the beltback on and went on my way. I had noticed one of the exhaust hoses I had used in place of the standard black rubber hose had started to melt from the motor getting so hot. Before I could make it home the hose had gotten a hole in it and started spraying saltwater everywhere in the bilge. Then I noticed the boat started running rough and it got progressively worse and worse as I tried to limp it home. So much so I eventually shut it down and called my dad to come tow me in.
Once I got home I replaced hoses and made sure to rinse the motor real good with fresh water and clean it real good. Took it back out the next weekend and it seemed to do ok for the day until I went to go back in and it started to act up and again and misfire real bad so I limped it back home at about 3200 rpm. Now I'm tearing my hair out of my scalp. and since then I try something else to fix it but every time I go out to test it's no dice.
So far Ive:
-changed spark plugs
-tested coils
-pulled injectors back out to see if clogged again
-cleaned grounds
-added grounds
-pulled and cleaned engine harness
-pulled and cleaned every electrical connection I could get to
-changed fuel filter
-ran lots of fuel system cleaner through it
-swapped fuel injectors from starboard side to port
-compression test even across all 8z
At an idle it seems to have a pop to it out of the starboard side. My current guess it's that maybe the cam position sensor or maybe more trash in the fuel and all injectors need to pulled and cleaned. Maybe plug wires?
Once I got home I replaced hoses and made sure to rinse the motor real good with fresh water and clean it real good. Took it back out the next weekend and it seemed to do ok for the day until I went to go back in and it started to act up and again and misfire real bad so I limped it back home at about 3200 rpm. Now I'm tearing my hair out of my scalp. and since then I try something else to fix it but every time I go out to test it's no dice.
So far Ive:
-changed spark plugs
-tested coils
-pulled injectors back out to see if clogged again
-cleaned grounds
-added grounds
-pulled and cleaned engine harness
-pulled and cleaned every electrical connection I could get to
-changed fuel filter
-ran lots of fuel system cleaner through it
-swapped fuel injectors from starboard side to port
-compression test even across all 8z
At an idle it seems to have a pop to it out of the starboard side. My current guess it's that maybe the cam position sensor or maybe more trash in the fuel and all injectors need to pulled and cleaned. Maybe plug wires?
#2
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Also I might add I'm only 20 and I bought the boat as a rebuild project for myself a year and a half ago. Did a full re-rig from the dash back. And with emerald coast poker run this weekend which is my hometown I'd really like to make it on the water
Last edited by Riley0114; 08-09-2017 at 04:40 PM.
#7
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Yes I heard that I was curious if someone could point me in direction where both cam and crank sensor are located so I could try and check them out to make sure both are getting clean connection. I believe per me serial number I have the old one that utilizes the old style cam sensor thats discontinued so Id have to find that aswell