Hi, this is my first post, EVER in this forum. I have an issue once my car is beat on for a little bit/gets to max op temp…

Ported, 3mm Apex seals, I am running a single exhaust, s4 turbo ecu, stock injectors, FCD, emissions block offs, brand new O2 sensor.

I was drifting this weekend, and the car was running splendidly, until it got to around 205 - 210 degrees. All of the sudden I started hitting a "Wall" of sorts. as if I lost a set of injectors, Because it happened where my secondaries kicked on (3800 rpm lean spot)

Freaked me out as this was the first shakedown of my new drift car, and it felt almost exactly as my blown motor did… Until it went below 4000, then it was like it was just fine???

So I shut the car off, checked as much as I could without pulling everything apart, and let it cool down. Started it up, same issue.

A fellow rotor fanatic asked what ecu I had, I told him s5, he thought I should reset the ECU and see if the problem happened again as;
“ s5 stock ecus hold codes... “

I disconnected the negative battery, hit the brakes a few times, and restarted the car, and to my amazement it worked!!!
I am running an S4 turbo II ecu, from factory, with a FCD from mazdaspeed. Notice how I said s5 ecus hold codes??? I have an S4, I said s5 out of error to the fanatic, luckily for me it helped!

Car ran great for a few laps and then it started happening again!!! (once it got a little warm, 200/205/210 ish , it started doing the 4000 rpm Wall/cutout thing.

This time I pulled the FCD to see if it had any effect, it didnt.
reset the ECU without the FCD car ran great, plugged FCD back in, car still ran great.

I dont think its the FCD....

Could it be the Thermo sensor??? Seeing as how my problem started once it got warm this is where I am...

 

I think your ECU Went bad.

 

has the ground for the ecu ever been inspected? Sounds like you have a rebuilt engine so I imagine it was taken care of. I would suspect the ecu ground or ecu itself at this point.

 

^double yes!

 

Thanks for the Feedback gents, I have figured out ( what I believe was ) the issue. My fuel pump wire was only getting static 8 volts, so I ran a wire from the fuel pump to a manual toggle switch, and have yet to see the issue after many a beating.
I will check the ECU Ground, as the car was not very well taken care of with the previous owner.

Thanks again for all of your help guys!!

 

mine just this morning started to feel like its getting the dreaded 3800 hesitation. Granted mines all original with 170k on her. Taking it apart to fix this weekend.

Glad you got it sorted out. Cheers