A friends father of mine bought a 93 with fairly new Mazda remain motor, the kid that he bought it from didn't have the money to keep it up. It was bought pretty much not runing. The car was a virgin car before he bought it.

We replaced the turbos, did the non seqential mod to the turbos, it has full 3 inch exhaust, cats are deleted, a Rick Stiles Race chipped ECU that was laying around, all emmissions was removed.

The car will start perfect, idles perfect, revs perfect with almost no load on the motor. But if you give it more throttle and/or put more load on the motor the ignition breaks up and car backs fire.

We changed the map sensor, fuel filter, fuel pump, coils, plugs, plug wires, and check and changed TPS.

If anyone has any suggestions please feel free to add them because we are at a dead end with car and clueless what could be going on with it.

 

sounds scary

how much boost you running? are you hitting fuel cut? what are you doing for boost control?

 

Do you have any idea what boost pattern it attains? With a full exhaust this is very important.

Dave

 

Check codes. You are likely experiencing "limp mode". You'll have a bunch of codes for stuff like AWS and other stuff you took off the car. Cross reference the codes in the manual and you'll find the one(s) that put the car into limp mode.

I've experienced the same symptoms with the OMP not being connected correctly and secondary injector.

 

would a vacuum leak cause your car to backfire?

 

Off throttle maybe, on throttle no.

 

I only wish that the car would run under enough load to build boost

 

Sicne you changed so much of the car's setup. Maybe it needs to be tuned correctly.

I'd say borrow a stock ecu, or preferably a PFC, with the map for a paralell turbo mode.

If the car runs better... get an after market ecu and an o2 sensor and tune it properly.

 

He said it was NS.

 

True, but the peak boost pressure is what I was interested in. You could call it a 'pattern'.

Dave

 

Did anyone hear me?

LIMP MODE.

You have a classic example of a car being in limp mode... Pretty much any load at all will cause the car to stutter/stumble, etc.

 

Jeff, I am convinced that the car is in Limp Mode. I just pulled the codes and I have quite a few to get rid of. What codes will put the car in limp mode? I have been looking in factory manual and haven't found yet a list of codes that will cause the car to go into limp mode.

 

I don't recall what page(s) the codes are listed on. Look through the manual and you'll see a description of what each code stands for. Further in the description you'll see it describes a symptom, some of them say fixes fuel and timing, or something along those similar lines. Those are the ones you'll need to go after.

You can forget about AWS, EGR, etc. You might get codes for those things but they don't affect the way the car runs ECU wise.

 

Thank you Jeff the car is runing fine now and the friends father is extreamly happy. This was really the first time I have worked on a FD with a stock ECU.

 

how come nobody has said how to stop limp mode/reset ecu???

well all you gotta do is to disconnect the battery for a min and step on the brake pedal during that time to drain all the excess battery power. then hook it back up and go for a test drive.

in anycase you seem to have fixed the problem so good job

 

dont people set their ecu's to run limp mode on a daily driver basis... because the ride is fine until 5k? im not stating, im asking.