Its been some weeks now and i am right back where i started. I was giving the car a trashing one nite when all of a sudden the car just started to backfire, first i taught it was just running rich but seems to not be the case. My E4 is fairly stock with a 5zingen exhaust. The car is running 10 psi.

Here is the rundown i what i checked so far:
Changed fuel pump
Install relay on the fuel pump
Changed fuel filter
Changed spark plugs (regapped to .22)
Changed to 560cc injectors
Exchanged MAF sensor from an evo5

Here is what i want to check again before i bring it back to the mechanic:
Coil packs from another evo 5
Timing (How can i check the timing on my E4?)
Run a diagnostic on the ecu to see if there is any codes (HOW DO I GO ABOUT CHECKING ERROR CODES ON MY E4?)

This is really frustrating me. Is there any thing that i might be missing from the list above to check? Any and all assistance will be most gladly welcomed. PLEASE HELP ME.

Quick question, when i take out the panel filter in the stock airbox and i just blew into the MAF sensor and the car just cuts of immediately, is that normal or it not suppose to happen?

 

What are the mods on the car? maybe it just needs a tune?

 

The car is fairly stock besides the 3" cat back exhaust it came with from japan. I still have the stock E4 ecu in the car. I had the car for about 3 months now and sent it to change the timing belt and perform a maintenance since them i find it give me the backfire when i got it back. If the car is not timed properly will it cause the backfiring? The car idles good in neutral at about 900 rpm.

 

Does ECU flash/tactrix work on the EVO IV? If it does you can use Evoscan and scantech to check for codes...see what the sensor outputs are, log most of the parameters that would affect yours are.

 

if you did get your timing belt changed that definitely could be why your backfiring! get your car looked at asap you dont want to mess anything up.

 

how can i check to make sure that the timing is correct and what is the base timing for the evo 4?

 

ok. I just did a error code check on the car by bridging pins 1 & 4. The errors i am getting are:

1 long flash with 2 show flashes= error code 12 (mass air flow sensor circuit malfunction)
1 long flash with 3 short flashes= error code 13 (Intake air temperature sensor)
2 long flashes with 5 short flashes= error code 25 (Barometric pressure sensor or MAP sensor)

Does the evo IV uses MAP sensors?
The MAF sensor and intake air temperature sensor are one unit?

I will cleared all the error codes on the ecu and change the MAF sensor from another car that works first then clear the code and try another MAP sensor to see which one will solve the problem.

 

ok. I just did a error code check on the car by bridging pins 1 & 4. The errors i am getting are:

1 long flash with 2 show flashes= error code 12 (mass air flow sensor circuit malfunction)
1 long flash with 3 short flashes= error code 13 (Intake air temperature sensor)
2 long flashes with 5 short flashes= error code 25 (Barometric pressure sensor or MAP sensor)

Does the evo IV uses MAP sensors?
The MAF sensor and intake air temperature sensor are one unit?

I will cleared all the error codes on the ecu and change the MAF sensor from another car that works first then clear the code and try another MAP sensor to see which one will solve the problem.

 

Ok. From what i checked it seems like i am getting crankwalk because the crank angle sensor is damaged due to the plate rubbing on the sensor. Will a faulty crank sensor cause the backfiring and RPM drop when boosting it between 3500 - 5000 rpm? I was reading somewhere that not all the time the crank angel sensor throws a CEL error code that suggests its bad. Any e4 owners ever had this problem b4?