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PCM question

AmericanRiceEater

AmericanRiceEater

New member
Hey if i install a tuned PCM in the next few days with already having headers and CAI (No pulley yet), will i feel any difference in power or anything else? Thanks :th_thumbsup-wink:
 




Rather B Blown said:
wouldn't the map sensor tell the pcm how much boost is coming in, and the pcm would send the right amount of fuel so it wouldn't run rich? I could be wrong
Click to expand...

i always thought it doesnt matter but thats a good point. id like to know because thats the reason i havnt gotton a tuned pcm yet.
 
The only way you run richer is while in PE mode, normally I don't even touch the cruise and idle fuel tables.
 
PE = Power Enrichment. It's what the PCM locks into for the commanded AFR when you pass a certain throttle percentage.

What Blue is really trying to say here though, is if the fuel trims are way off, then your PE will be off. Being that this all goes off of your LTFT and STFT average, if the car is running rich to begin with, then your Power Enrichment will be rich, and the same goes to if it's lean.

Either way, out of both, you obviously want it to be rich, but it won't be as bad as most people think pulley wise.
 


thats quite a drive haha. so if i get a canned tune, i wont be dumping all this extra fuel into my engine since i dont have a smaller pulley?
 
lol i meant for americanrice eater as he is only 75 minutes away...also the pcm will command fuel based on the maf reading and the settings for fuel ratio in the computer. u can have no pulley or a 2.6 pulley and the computer will still run off the maf to determine gas based on the calculation for desired afr. your injectors wont hold this of course but im saying this to make a point. now if the maf reading is wrong or tuned wrong of course the computers calculation will be wrong but thats it. ive gone from a 3.4 pulley to a 3.25 and now im at a 3.1 and ive yet to need to retune the pcm for afr or maf at any boost rate and i have consistently run within +/- 3 for my fuel trims and afr
 
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