I installed my custom torque brace today, went out for a spin. drove it carefuly around the block and then gave it just a bit of power on corner exit, not WOT. suddenly i heared a strange sound, like something blew maybe, i cant tell exactly. i immediately let off the gas, i was in the middle of the road so i had to pull to the side. the car behaved normaly like it should on very low RPM (same vacuum, cant talk about idle speed as my tachometer is not working but it sounded OK) but was backfiring as soon as i gave it just a bit of gas. oil pressure was OK, oil temperature was also OK, water temperature on stock gauge looked good. i pulled to the side, checked the map sensor, it was not poped off but then we noticed that the drive belt was off (the one on the driver side, not the one that drives air pump). we put it back but the car would crank but not start. does this have something to do with belt going off or i blew the engine and belt was just a coinsidece?

 

here is the picture where we installed torque brace. could it hurt something there? or cause belt to fall of?

 

The other belt just runs the A/C and P/S. You can run the car without that belt if you don't want to take advantage of those two items.

 

the belt blowing off is a coincidence.

 

what could this be? blown engine? it just wont start and neither has any signs of trying to.

 

Start by checking the usual things: spark plug wires (make sure one didn't pop off), maybe some bad gas, etc..

 

the car was idling like usual, it just didnt have power and was backfiring when giving gas. I turned it off myself to put the belt on. can a car idle with 1 or 2 plugs wires poped? afterwards it wont start. I will check plugs and wires tomorrow. i have new plugs and wires.

 

Maybe the belt did something to the CAS or its wiring as it came off...

Dave

 

thats a good point. could the car idle well with this sensor or wiring damagded? as i said before, the car was idling ok, it just didnt have power and was backfiring when giving gas. i turned it off, put the belt and could not start it anymore.

 

i removed spark plugs today., they were dry. removed the fuel pump relay and cranked the engine to listen to compression. pshh sounds on both rotors were consistent and seemed even. considering that plugs are dry, can i assume that the problem is fuel related?

 

could be.
fuel, spark, compression is what is needed for an engine to run.

I believe you can ground out the F/P and GRN in the diagnostic port and listen for the fuel pump. Did you check all your fuses? spray some starter fluid in and see if it fires up on that, if it does you have a fuel problem

 

today i grounded F/P and GND, opened fuel tank cap and turned ignition on. there was a continuous weak sound like pssssssssss... is this it? is this the fuel pump sound? on other cars it sounded louder.

 

can you hear fuel flowing through the fuel rails? the best way to test the pump is with a gauge at the rail obviously.

 

This is really interesting... puzzling.

I know you said that you put the belt back on, but it makes zero sense that it would come off to begin with unless something else happened. I have a hunch ... check the four bolts that hold your crank (e-shaft) pulleys in place and make sure that they're all there and/or not snapped. What I'm getting at here is perhaps a couple of them came out or snapped and caused the pulley to wobble a bit and throw your accessory belt. When you re-installed it, tightening the new belt possibly caused the entire crank pulley assembly to sit at a bit of an angle, which is affecting the reading on the crank angle sensors and preventing your ECU from getting proper information.

 

thanks for input. now i'm leaning more towards ignition problem. the car was not runing right even before i turned it off. the idle was good but no power at all with backfires. crank angle sensor problem makes sense to me.

 

finaly had some time to take care of my car. so me and my brother bought a led and 680ohm resistor to check for codes. It turned out to be a crank angle G sensor, code #3. the sensor was torn off completely with wires hangin out. I guess when the car started jumping somehow it poped off and got smashed by the pulley. Now i'm going to buy that and FC T2 thermoswitch as well. There is no Mazda dealer or rotary specialist in my country so ill have to order it.