actual vs. commanded timing
actual vs. commanded timing I have been street tuning, and ive noticed that around the peak torque band, my scan will show timing pulled about 3 degrees. It is not KR related as the scan shows zero knock. I previously pulled some timing in this range to get rid of that KR.
what else pulls timing? I checked the spark tab in hp tuners and IAT can pull timing, but only at intake temps above 100 deg. this scan showed 72 deg IAT.
Does the PCM pull timing to maintain the actual AFR to commanded AFR? This is the only other thing I can think of. Despite the timing pull (or perhaps because of it), the car does maintain commanded AFR thru the WOT pull and runs great.
what else pulls timing? I checked the spark tab in hp tuners and IAT can pull timing, but only at intake temps above 100 deg. this scan showed 72 deg IAT.
Does the PCM pull timing to maintain the actual AFR to commanded AFR? This is the only other thing I can think of. Despite the timing pull (or perhaps because of it), the car does maintain commanded AFR thru the WOT pull and runs great.
Last edited by dreww; Sep 28, 2014 at 05:35 PM.
ok, I zero'd out the "burst knock retard vs RPM" table and setup a histogram from burst KR. put the tune in, scanned it again. no KR and no burst KR at all, but still pulling timing in the same cell(s).
The only thing I can think of is its using the low octane table, but only for the 4800rpm cells. That also doesn't make sense, wouldn't it use either the HO table or the low HO table? not pick and choose which table it wants during a pull?
The only thing I can think of is its using the low octane table, but only for the 4800rpm cells. That also doesn't make sense, wouldn't it use either the HO table or the low HO table? not pick and choose which table it wants during a pull?
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In my limited experience I think the PCM uses zones for setting low/high ratio... kinda like LTFT. And if you are 3deg below commanded, total is prob about 6deg cause AFR adv is separate channel (unless you zeroed it).
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ok, made a timing retard histogram and scanned again. There is no timing being retarded, no KR, no burst KR. the car is in fact using the low octane table.
I copied high table to low and scanned again. the timing came back and so did KR. I think Im just getting shitty gas, even though we have 93 octane here and I always fill up with that. Time for chevron, shell or similar I think.
I copied high table to low and scanned again. the timing came back and so did KR. I think Im just getting shitty gas, even though we have 93 octane here and I always fill up with that. Time for chevron, shell or similar I think.
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Verdad Gallardo in the 5200 and 5600 rpm timing is a little higher. about 24 degrees
IAT's high? Have you checked the plugs? There is no reason you shouldn't be able to handle 24* if all conditions are stable. I personally don't think 24* is too high for a "stock" motor. Much more than that, may start to diminish power. We are talking at WOT (100%tps) right? I assume because the 4800rpm, but just want to make sure. I am by far no expert, but I would love to help and since you keep us up to date. Once you have it narrowed down, we all win lol
no, the coolant temp and intake temps were not in the range required to pull timing. I checked those tables first thing. Im gonna run another scan tonight with fuel from a different station. It should run full hi octane table timing without any KR like it did before that last shitty tank of gas.
this knock was only at WOT, I have no partial throttle knock. ill have my laptop and attempt to post the scan tomorrow. thx
this knock was only at WOT, I have no partial throttle knock. ill have my laptop and attempt to post the scan tomorrow. thx