What the hell?

[Drumfreak]

So I'm getting on the freeway in 2nd gear and floor it. The boost spikes to about 11 on the gauge then boom the car shuts down. Like it hit fuel cut but the car stopped running. I coast to a decent spot to pull over in. I get out expecting to see a huge gash in the block or oil oozing from somewhere and started thinking about an engine build. I checked all the piping to see if something blew off and nothing seemed wrong. I tried to start the car and it turned over just fine but wouldn't start. I then noticed when the key is in the ON position that my temp gauge is all the way up. The car wasn't overheated at all so what is going on, right? I figured it was something electrical. I disconnect the battery and start checking fuses. I looked at all the ones inside the car and they were fine. I then looked under the hood at all the 10 and 15 amp fuses and they were fine too thinking not to check the bigger important fuses like the 30 amp ones and above so I go back to the drivers seat and sit there frantically calling people to ask opinions. After the panic I decided to double check the fuses and then checked the 30 amp ones under the hood and the first one was fried. I called my GF. She brought me to the nearest Checker to get a new fuse (of course I bought 2 just in case) and put the fuse in and the car was perfectly fine. I even floored it a bunch and it ran great. I got home and checked my manual to see what fuse it was. It's the number 10 fuse underneath the hood labeled "Engine Control Unit" in the manual. My buddy and I figure it's maybe from the overboosting causing the injectors to max out the duty cycle or something along those lines causing the ECU to shut everything down. Anyways, very scary. I thought I was a member of the Zoom Zoom Boom Club. I will be ordering the Apexi AVCR EBC as soon as I possibly can, and I will be removing my mbc because spikes are horrible for your car. Happen to anyone else? Thought I would share and thanks for reading, Joe M.

[Maxx Mazda]

Subbing for info. Shitty luck man.

[Drumfreak]

Anyone have advice before I pass out? I don't get it. I should add that I have blown a fuse before. I can't remember which one but I do recall the temp gauge malfunctioning and saying it was way hot. My car sat there a good hour and a half before I got it running and the temp never went down. I'm led to believe that it's a safety feature of some sort or the blown fuse confused the temp gauge and then the computer wouldn't let the car start cuz it was tricked into thinking it was overheated. Fucking newer cars.

[Maxx Mazda]

When the temp gauge has no signal, it goes WAY hot. I unplugged mine when I blew my engine and it read off the scale hot.

[Drumfreak]

When the temp gauge has no signal, it goes WAY hot. I unplugged mine when I blew my engine and it read off the scale hot.
That makes sense. Maybe this was just random and will never happen again.

[Drumfreak]

Well the car keeps blowing the same fuse. It's to the point where I turn it over and it blows the fuse. My mazda tech said the only two reasons for that fuse to blow would be a malfunctioning injector or a short somewhere within the wiring harness for the ecu. Were going to test the injectors this weekend with a multimeter. If they are fine then it's going to be like a needle in a haystack trying to find the short. Boo. Good thing I got paranoid and ordered the Greddy Profec II EBC becuase I thought my spike from my mbc was contributing to these issues, but when my car is running again I will have an EBC to install so that's exciting.

[Fudgie]

You still running the dsm afc? That tags onto an ecu power wire. Make sure those connections aren't shitty or chaffed against the metal cover over the ecu.

[Drumfreak]

You still running the dsm afc? That tags onto an ecu power wire. Make sure those connections aren't shitty or chaffed against the metal cover over the ecu.
Good call. I didn't really think about checking that. As soon as I'm outta work and home I will be searching.

[Kansei]

ooh ooh ooh this exact thing happened to my car! The primary oxygen sensor's heating circuit was shorting out as soon as the sensor warmed up, blowing the fuse that also happens to control the fuel injection system.

If your car is blowing the fuse after just a minute or two of driving and then cranks but won't actually start at all, try unplugging the primary oxygen sensor and seeing what happens then. The car will run like crap but shouldn't die. If that works, just get a new primary oxygen sensor and you're good to go!

[Drumfreak]

ooh ooh ooh this exact thing happened to my car! The primary oxygen sensor's heating circuit was shorting out as soon as the sensor warmed up, blowing the fuse that also happens to control the fuel injection system.

If your car is blowing the fuse after just a minute or two of driving and then cranks but won't actually start at all, try unplugging the primary oxygen sensor and seeing what happens then. The car will run like crap but shouldn't die. If that works, just get a new primary oxygen sensor and you're good to go!
It's blowing without even driving it. It was the fuse under the hood labeled number 10 in the manual which says injectors and ECU. It's the bottom fuse in the 2nd row from the far right row of fuses. Is this the one that you were blowing. I will try this method to see if this is the case. Thanks for the heads up advice!! Just wondering, did your car throw a CEL when this was happening? No CEL's for me so far.

[Drumfreak]

Thanks to everyone who gave advice but the car is now fixed. There was a short. A wire near the throttle body had worn threw and was grounding itself. Anyways, easy to fnd and easy to fix. God it feels damn good to have it working again.

[Kansei]

There was no CEL for me either.. since the ECU, fuel injection, etc was off.

glad you got it fixed!

[03.5MSP]

YAY, i got the same issue. Now i have to find the stupid ground wire, that is messed up. Which wire near the TB was bad, im hoping mine is the same.

thanks,
Marko

[Drumfreak]

YAY, i got the same issue. Now i have to find the stupid ground wire, that is messed up. Which wire near the TB was bad, im hoping mine is the same.

thanks,
Marko
The wire came from the clip that was fastened to the top of the stock IC pipe into the throttle body right next to the throttle body. Since I dont have stock IC piping I lost that bracket and that was zip tied in a bad spot apparently. I hope that makes sense.

[03.5MSP]

The wire came from the clip that was fastened to the top of the stock IC pipe into the throttle body right next to the throttle body. Since I dont have stock IC piping I lost that bracket and that was zip tied in a bad spot apparently. I hope that makes sense.

What did you do to fix it, I have a perrin fmic and piping, and i did move some stuff around too. Damn this sucks.

[03.5MSP]

I checked every wire and its mother, and still nothing. Im going to take the car to mazda and see if they can help.

The stupid thing is I put the car in neutral from 2nd, since i was comming up to a stop sign. I was slowing down and the car just died, so i slowly rolled to the side of the road. Luckly this shit happened only a block away from home. I wasnt boosting or driving hard. Its so gay, i wish my engine blew so I knew what was wrong and I could fix it. Plus I would go forged. (rockon)

[Drumfreak]

What did you do to fix it, I have a perrin fmic and piping, and i did move some stuff around too. Damn this sucks.
My hiboost kit came with a bracket but it was lost per my dad. Its a long story. Anyways, I just ziptied that clip to my brake booster vac line. Not the cleanest but its up and out of the way. Hope you can find the problem. YOu know you dont need to blow the motor to forge it. You can build whenever you want. It would be cheaper to not blow then build. You could use your existing block and head then. Good luck.

[03.5MSP]

My hiboost kit came with a bracket but it was lost per my dad. Its a long story. Anyways, I just ziptied that clip to my brake booster vac line. Not the cleanest but its up and out of the way. Hope you can find the problem. YOu know you dont need to blow the motor to forge it. You can build whenever you want. It would be cheaper to not blow then build. You could use your existing block and head then. Good luck.

Yeah, Im planing to go forged at the end of this year. I just need to save up some more. Im taking my car to mazda and have them fix it. Thanks for all of your help.

[bazooka joe]

just had the same fuse blow for me....i've got a rat's nest of wires i hacked for the mpi and now my o2 clamp....i bet something is shorted out...i had a friend sitting in the passengers seat and he may have pressed rahter hard on the ecu panel and nicked a wire...not his falut..