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Old 08-13-2018, 01:04 PM
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Default 1998 502 mpi

Hello guys & thanks for the add.
I have a 98 Baja 272 with a 502 MPI & M1 ProCharger. I'm having issues with the engine breaking up & loosing power above 3000 rpm. The ECM was flashed back in the early 2000's when the ProCharger was installed. This season I had the injectors serviced & tested & they came back with no issues. I then installed a MSD 6M box, coil cap & rotor, 8.5mm wires & distributor & I'm still having the same issue. We put it on the scanner & did some pulls this weekend & found out that the timing is at 36 degrees at 3000 rpm & then starts retarding quickly after that all the way down below 20 degrees at 3600. All sensors appear to be normal, but not getting any readings from the knock sensor. Any help will be most appreciated
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Old 08-13-2018, 05:06 PM
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Whats your fuel pressure gauge on dash reading when it breaks up? Whats your vacuum boost gauge reading?
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Old 08-13-2018, 05:30 PM
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Fuel pressure is 40-42 boost is showing 0
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Old 08-13-2018, 05:37 PM
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Maybe the Knock module, maybe bad knock sensor.
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Old 08-13-2018, 05:38 PM
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Anyway to check the knock sensor?
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Old 08-13-2018, 06:52 PM
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I think it will run if you unplug the module
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Old 08-14-2018, 11:12 AM
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Mefi1 or mefi3? Mefi3 doesnt have knock module, if its mefi1 i can send you a known good knock module 30$ shipped to your door if u want to try one, Smitty

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Old 08-14-2018, 11:22 AM
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Concur, sounds like knock sensor is triggering and killing the timing.
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Old 08-14-2018, 12:38 PM
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MEFI1. Where is the knock module located? My manual only shows the knock sensor. Also, correct me if I'm wrong< there is only one knock sensor.
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Old 08-14-2018, 02:19 PM
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Hey Smitty just found this old thread. Should I consider the Holley setup?
http://www.offshoreonly.com/forums/g...-mefi-1-a.html
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