Injectors randomly increase cycle rate
Discussion
Hey guys
Had an odd issue with my RX7. Back in May we tried mapping the new ecu after the engine was lightly modified with new intercooler, intake and exhaust. The ignition system wasn't able to ignite all the fuel and the mapping had to be abandoned.
Since then I have replaced the coils, plugs and HT leads as well as wire a direct battery feed to the coil loom.
When the engine is warm it idles around 750rpm and has an injector cycle of 3.5%. However out of the blue the injector cycle sometimes jumps to 6.5-7% causing the engine to rock, idle to drop near 400 and a lot of black smoke. It will run ok when moving and return to the normal 3.5% when I next stop.
Does this sound more like a sensor issue? My thinking is of it were a vacuum leak (common on RX's) then it would be all the time. Or could it be injector related like a weeping o-ring?
Had an odd issue with my RX7. Back in May we tried mapping the new ecu after the engine was lightly modified with new intercooler, intake and exhaust. The ignition system wasn't able to ignite all the fuel and the mapping had to be abandoned.
Since then I have replaced the coils, plugs and HT leads as well as wire a direct battery feed to the coil loom.
When the engine is warm it idles around 750rpm and has an injector cycle of 3.5%. However out of the blue the injector cycle sometimes jumps to 6.5-7% causing the engine to rock, idle to drop near 400 and a lot of black smoke. It will run ok when moving and return to the normal 3.5% when I next stop.
Does this sound more like a sensor issue? My thinking is of it were a vacuum leak (common on RX's) then it would be all the time. Or could it be injector related like a weeping o-ring?
"tried mapping" seems appropriate term.
If the ecu is opening the injectors for longer which will result in a higher duty cycle....then it is doing it for a reason. Your mapper would be able to look and see which settings are doing this.
The rough running may be a symptom, or also a part of the cause...again, your tuner has the car/engine in front of him and all the relevant information from the ecu/sensors, they should be able to diagnose what is going on.
But given the sparse information provided here....it makes remote diagnosis incredibly difficult, but one thing is for sure, it wont be doing it at random.
If the ecu is opening the injectors for longer which will result in a higher duty cycle....then it is doing it for a reason. Your mapper would be able to look and see which settings are doing this.
The rough running may be a symptom, or also a part of the cause...again, your tuner has the car/engine in front of him and all the relevant information from the ecu/sensors, they should be able to diagnose what is going on.
But given the sparse information provided here....it makes remote diagnosis incredibly difficult, but one thing is for sure, it wont be doing it at random.
Sorry some more info.
Car has been mapped to 0.6bar boost any more than this resulted in ignition breakup. The mapped believed a weak spark was the cause.
I am still running that map as we couldn't resolve the issue there and then.
Engine is running closed loop and uses an o2 sensor and MAP for fuel from my understanding.
Car has been mapped to 0.6bar boost any more than this resulted in ignition breakup. The mapped believed a weak spark was the cause.
I am still running that map as we couldn't resolve the issue there and then.
Engine is running closed loop and uses an o2 sensor and MAP for fuel from my understanding.
Daston said:
I am still running that map as we couldn't resolve the issue there and then.
You need somebody who understands your ECU configuration to diagnose and resolve the problem. It will need a thorough understanding of the algorithms being used and how they've been calibrated. The person who tried to map it for you is the most obvious candidate. Asking people to speculate about possible causes without that understanding is a waste of time.Find someone who actually knows what they are doing and get them to look at the car.
It may be weak spark...but 0.6 bar is pretty damn low boost....of course we know nothing about your ignition system or it's condition etc.
Likewise we know nothing about how good or bad closed loop fuel control has been setup.
Again....the ecu will not be doing anything at random, knowingly ( or most likely not ) your tuner will have told it to do whatever it is doing
Which is why tuning needs cone by someone competent both in terms of knowing what engines want, how fuel/ignition systems work and how the actual ecu/software work.
Sadly in todays world of mappers/tuners everywhere...such people above are few and far between....but many of them try.
It may be weak spark...but 0.6 bar is pretty damn low boost....of course we know nothing about your ignition system or it's condition etc.
Likewise we know nothing about how good or bad closed loop fuel control has been setup.
Again....the ecu will not be doing anything at random, knowingly ( or most likely not ) your tuner will have told it to do whatever it is doing
Which is why tuning needs cone by someone competent both in terms of knowing what engines want, how fuel/ignition systems work and how the actual ecu/software work.
Sadly in todays world of mappers/tuners everywhere...such people above are few and far between....but many of them try.
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