rpm rises on idle to 2000 without the throttle !!. 454 mpi procharger ** help !!!
06-02-2009, 09:08 PM
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rpm rises on idle to 2000 without the throttle !!. 454 mpi procharger ** help !!!
hi friends.. need some advice.
i own a 1998 american offshore 26 nx with a factory setup 454 mpi with a procharger.
boat starts up fine. then after about 5 minutes of driving, the rpm on idle goes to 2000 / 2100 . no matter what i do, it wont come down.
we did the same thing and left the motor running for 30 minutes out of the water , but wont replicate the same problem.
we put it in the water again today, let it warm up for 20 minutes dockside. rpm was beautiful at 1000.
then got in the boat to go for a ride and after 3-4 minutes on idle to get out of the marina area, shot up to 2000 and ran rough.
we changed the fuel pressure regulator with a new one last week, we went through the distributor,checked the advance, no leak on any vacuums, we are beat !
with the throttles down, how can it shoot up to 2000 ? maybe the map sensor or the ecu is sending info to the distributor to change the timing ? why ? basically, the only way rpm can rise on it's own without giving it throttle is through the timing changing...
but what is causing the timing to get a message to change and shoot up the rpm ?
we unplugged the map sensor and the engine dies out. we tested the temp sensor and unplugged it thinking it was sening a cold engine message causing the rpm to rise for warm up, but that didnt do anything, the sensor is working fine...the computer is a delphi/gm... i dont see a sticker of anything like arizona speed ....same for the map sensor. all seems like it is stock ?? again, mayobe i have another issue...anyone have any ideas ?
i sold the boat and was going to a 42 fountain... but this is throwing my new deal out.. i must get this resolved asap and deliver the boat to the buyer working as it should , or else, no 42 fountain !
help !
i own a 1998 american offshore 26 nx with a factory setup 454 mpi with a procharger.
boat starts up fine. then after about 5 minutes of driving, the rpm on idle goes to 2000 / 2100 . no matter what i do, it wont come down.
we did the same thing and left the motor running for 30 minutes out of the water , but wont replicate the same problem.
we put it in the water again today, let it warm up for 20 minutes dockside. rpm was beautiful at 1000.
then got in the boat to go for a ride and after 3-4 minutes on idle to get out of the marina area, shot up to 2000 and ran rough.
we changed the fuel pressure regulator with a new one last week, we went through the distributor,checked the advance, no leak on any vacuums, we are beat !
with the throttles down, how can it shoot up to 2000 ? maybe the map sensor or the ecu is sending info to the distributor to change the timing ? why ? basically, the only way rpm can rise on it's own without giving it throttle is through the timing changing...
but what is causing the timing to get a message to change and shoot up the rpm ?
we unplugged the map sensor and the engine dies out. we tested the temp sensor and unplugged it thinking it was sening a cold engine message causing the rpm to rise for warm up, but that didnt do anything, the sensor is working fine...the computer is a delphi/gm... i dont see a sticker of anything like arizona speed ....same for the map sensor. all seems like it is stock ?? again, mayobe i have another issue...anyone have any ideas ?
i sold the boat and was going to a 42 fountain... but this is throwing my new deal out.. i must get this resolved asap and deliver the boat to the buyer working as it should , or else, no 42 fountain !
help !
