@@SocalMarineUSA thanks I have a no fire issue going on now after winter storage. I have continuity between the grey (turns to white at harness connection) and ground. It only shorts to ground when the grey connector on the coil is connected. I can't find any abrasions so far. Does this sound like a burned out ignition coil?
Hello Socal Marine, Im having a problem with my 502 MPI, one day it was running great, like it has been since I got the boat (4 years aprox.), and the next day it would not rev past 2700 - 2800 rpm, throttle wide open. I am mechanically inclined but not a professional, I did replaced the IAC valve, PCV valve, spark plugs, TPS, made sure the throttle body is clean and working properly, Checked fuel pressure (45 + psi), replaced all 8 injectors, checked if they were getting power with this little lights you plug to the inj. plugs, they all lit up, sent the ECM to California to have it tested, they say its all good, but still, the problem persist. Seems like there is not techs here in west Texas than can work or know those engines. Do you have any suggestion for me to check?? Im trying to avoid a looooong tow the the closest guy, about 6 or 7 hrs driving time. Thanks for anything you would suggest me to check. Its been very frustrating.
sounds like it could be in limp mode - any vibrations? doubt the coupler wd be the issue- www.offshoreonly.com/forums/general-q/299138-502-mpi-nightmare-2.html - "All stupid electrical problems are a bad ground." Check the grounds! make 1000% they are shiny greased with dielectric grease.. pos and negative. Can always try run a sep 12 or 14ga ground wire from batt - straight to where the ECU bolts up (intake somewhere)...
@@SocalMarineUSA Thanks for replying brother! Vibrations? yes, sounds to me not all the cylinders are firing, even at idle, hard to tell tho, its got a cam, headers (loud) etc. One of the things is doing, it starts fine, but does not holds idle, got to crack the throttle open a little so it does not die, it used to hold idle before with the throttle closed all the way to the stop. All of this started when I noticed the block had cracked for not winterizing it, (my fault). I noticed it once the boat was in the water, it would not rev up past 2800 rpm, then I stopped, check the oil, found water and oil mixed, and thought to myself that was the reason it would not rev up, got a new block, had the heads checked, got new rings, bearings, gaskets, etc, assembled the whole engine, put boat back in the water, and still, would not rev up. Could the issue be related to the cracked block?, visually, the block was the only thing I noticed wrong when I opened up the engine. When I did put it back together i made sure all the grounds and connections were clean and rust free. Also, I have a raw water cooling syst. Thanks again for replying back to me
Thank you, you help me find my problem with the ignition module.AAA+
Great video! Thanks for the helpful info.
where was your short at?
grey (tach) wire and the block, it got pinched between the bracket and the block, intermittently shorting randomly!
@@SocalMarineUSA thanks I have a no fire issue going on now after winter storage. I have continuity between the grey (turns to white at harness connection) and ground. It only shorts to ground when the grey connector on the coil is connected. I can't find any abrasions so far. Does this sound like a burned out ignition coil?
Hello Socal Marine, Im having a problem with my 502 MPI, one day it was running great, like it has been since I got the boat (4 years aprox.), and the next day it would not rev past 2700 - 2800 rpm, throttle wide open. I am mechanically inclined but not a professional, I did replaced the IAC valve, PCV valve, spark plugs, TPS, made sure the throttle body is clean and working properly, Checked fuel pressure (45 + psi), replaced all 8 injectors, checked if they were getting power with this little lights you plug to the inj. plugs, they all lit up, sent the ECM to California to have it tested, they say its all good, but still, the problem persist. Seems like there is not techs here in west Texas than can work or know those engines. Do you have any suggestion for me to check?? Im trying to avoid a looooong tow the the closest guy, about 6 or 7 hrs driving time. Thanks for anything you would suggest me to check. Its been very frustrating.
go join my fb group Boat Tech Help - Mercruiser, Volvo Penta, Outboards, Engines Q&A and post there!
sounds like it could be in limp mode - any vibrations? doubt the coupler wd be the issue- www.offshoreonly.com/forums/general-q/299138-502-mpi-nightmare-2.html - "All stupid electrical problems are a bad ground." Check the grounds! make 1000% they are shiny greased with dielectric grease.. pos and negative. Can always try run a sep 12 or 14ga ground wire from batt - straight to where the ECU bolts up (intake somewhere)...
@@SocalMarineUSA Thanks for replying brother! Vibrations? yes, sounds to me not all the cylinders are firing, even at idle, hard to tell tho, its got a cam, headers (loud) etc. One of the things is doing, it starts fine, but does not holds idle, got to crack the throttle open a little so it does not die, it used to hold idle before with the throttle closed all the way to the stop. All of this started when I noticed the block had cracked for not winterizing it, (my fault). I noticed it once the boat was in the water, it would not rev up past 2800 rpm, then I stopped, check the oil, found water and oil mixed, and thought to myself that was the reason it would not rev up, got a new block, had the heads checked, got new rings, bearings, gaskets, etc, assembled the whole engine, put boat back in the water, and still, would not rev up. Could the issue be related to the cracked block?, visually, the block was the only thing I noticed wrong when I opened up the engine. When I did put it back together i made sure all the grounds and connections were clean and rust free. Also, I have a raw water cooling syst. Thanks again for replying back to me