Blowing internal power fuse (f1) under load ms3pro

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Blowing internal power fuse (f1) under load ms3pro

Postby Bke36 » Sun Oct 15, 2017 1:10 pm

I've been having this issue with my e36 drag car where under load at about 4500 rpm it blows the f1 power fuse on my ms3 pro. The engine is a turbocharged bmw m52 using all stock sensors. Everything works fine until it starts going into boost and making power, that's when it pops the fuse. I had a new harness made for it and has been gone thru with no luck finding the problem. The connections to the ecu are, 6 2200cc Bosch injectors, 6 ignition outputs to Toyota denso coils (externally powered), ait, clt, tps, crank, cam, aem 5 bar map sensor and pink wire for afr input from an innovate scg-1. At first thought it could be a grounding issue so I ran a 0 gauge wire from the battery to the engine block and grounded the coils to the block with no luck. Then wired the ecu directly to the battery (both +/- all 6 grounds plus the logic ground) and the problems still there. Even bypassed the fuse panel and powered just the fuel pump and ignition coils to rule out back feed from another component and still pops the fuse. To rule out the ecu being faulty, we ran it in my tuners car and it works flawless. Also ran a test on the injectors and coils thru the ms3pro and those all seem to work fine and doesn't pop the fuse when testing only when the engine is running and under load. I've been fighting with it for 3 months now and I'm about ready to give up on it. Any help I can get will be greatly appreciated!

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Re: Blowing internal power fuse (f1) under load ms3pro

Postby Matt Cramer » Mon Oct 16, 2017 8:00 am

I'm wondering if the MAP sensor is misbehaving. Try pumping up the MAP sensor reading with a bicycle pump with the key on and engine off, and see if that pops the fuse.
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