Lean Spikes on Decel and Weird IAT Table...Help!
07-25-2009, 01:12 PM
#1
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Lean Spikes on Decel and Weird IAT Table...Help! Hey guys,
I was just wondering if anyone could take a look at this scan and my tune. I get some REALLY lean spikes on decel sometimes and I just wanted to know if that was kind of normal or if I needed to change something around in my tune?
Here is an example:
I also noticed that my tuner zero'd out the IAT table below 140*. (the -6 above 140* is for my HSW interface to pull timing for nitrous) I was wondering if the IAT retard is something that I should put back in or if it would be OK to leave it out? I am working on my own tune but I was hoping to leave this tune in until mine is done. If it is not safe I will pull it though.
Here is the tune and the full scan (I am spraying at the WOT parts that is why the IAT went to 158*+):
I was just wondering if anyone could take a look at this scan and my tune. I get some REALLY lean spikes on decel sometimes and I just wanted to know if that was kind of normal or if I needed to change something around in my tune?
Here is an example:
I also noticed that my tuner zero'd out the IAT table below 140*. (the -6 above 140* is for my HSW interface to pull timing for nitrous) I was wondering if the IAT retard is something that I should put back in or if it would be OK to leave it out? I am working on my own tune but I was hoping to leave this tune in until mine is done. If it is not safe I will pull it though.
Here is the tune and the full scan (I am spraying at the WOT parts that is why the IAT went to 158*+):
07-25-2009, 01:50 PM
#2
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Spray should drop your IAT unless you're using a
"tricker" gizmo. But the IAT takes a long (relatively)
time to respond, in itself.
DFCO may be responsible for lean spikes, this mode
also puts advance to 0. You can see the advance
"blip" precede the lean dip, the time skew is your
exhaust gas transport delay and WB processing time
and/or filter lag.
"tricker" gizmo. But the IAT takes a long (relatively)
time to respond, in itself.
DFCO may be responsible for lean spikes, this mode
also puts advance to 0. You can see the advance
"blip" precede the lean dip, the time skew is your
exhaust gas transport delay and WB processing time
and/or filter lag.
07-25-2009, 07:36 PM
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The IAT table is sort of a "crutch" to help you do
stuff like avoid hot-weather ping.
If I were going to trick the IAT, I'd trick it to a
cold temp (which is more realistic given the physics
of what's going on) and put N2O retard in the -40
column instead. But you might then also have to
touch ECT (there is a closed loop enable that looks
at ECT vs IAT). Though at WOT it probably doesn't
matter. Just a lot of interactions, maybe you're
better off staying where you're at. Anyway, if you
don't ping then you don't need IAT spark retard.
Though conversely, you might use the table to
push more spark if tolerated, at temps away from
your tuned-at point.
I use it to try and tamp down summertime, AC-on
ping myself.
DFCO is more of an annoyance (bucking, junk
data in the logs that has to be filtered) than a
real problem. It saves you a little bit of gas.
stuff like avoid hot-weather ping.
If I were going to trick the IAT, I'd trick it to a
cold temp (which is more realistic given the physics
of what's going on) and put N2O retard in the -40
column instead. But you might then also have to
touch ECT (there is a closed loop enable that looks
at ECT vs IAT). Though at WOT it probably doesn't
matter. Just a lot of interactions, maybe you're
better off staying where you're at. Anyway, if you
don't ping then you don't need IAT spark retard.
Though conversely, you might use the table to
push more spark if tolerated, at temps away from
your tuned-at point.
I use it to try and tamp down summertime, AC-on
ping myself.
DFCO is more of an annoyance (bucking, junk
data in the logs that has to be filtered) than a
real problem. It saves you a little bit of gas.
07-26-2009, 10:00 PM
#7
Yeah DFCO isn't a problem. It helps to preserve cats and also helps some with fuel ecomony. I max mine out so that just about anytime I'm off the gas pedal there is no fuel.
You can turn it off by simply raising the DFCO enable temp. Or if it's bothering your AFR error% then just filter it out of the histogram.
You can turn it off by simply raising the DFCO enable temp. Or if it's bothering your AFR error% then just filter it out of the histogram.
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07-26-2009, 11:23 PM
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Well with reguards to the IAT table I had to put some retard back in. I scanned a long drive today with a bunch of traffic on and off and I was getting some knock retard at WOT. I just cut the stock table in half for now and I'm going to scan another drive tomorrow. The good thing is that on nitrous I get no retard so at least I know thats safe enough!
Can someone help me out in telling me how to turn down the sensitivity of the knock sensors just a little bit too? I did get some false knock in addition to the real knock so I would like to tune that out a little bit.
I'm going to leave the DFCO for now though until I learn a little bit more about it.
Can someone help me out in telling me how to turn down the sensitivity of the knock sensors just a little bit too? I did get some false knock in addition to the real knock so I would like to tune that out a little bit.
I'm going to leave the DFCO for now though until I learn a little bit more about it.
07-26-2009, 11:56 PM
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26-29* I was getting up to 3* (with one spike of 9* which dropped RIGHT to 0 so I'm guessing it was false and based on my loud *** header ticking) of KR at WOT between 97*-110* IAT.
07-27-2009, 12:21 AM
#13
Have you done any airflow correction? The wideband is kind of all over the place in the nitrous log.
Also what size shot are you running? It doesn't appear to be much. I would say just not run as much timing and don't worry about the timing tricker. At frame 7759 you're showing 14.74 AFR and 31.5 degrees of timing. That's not really a good thing on nitrous.
Also what size shot are you running? It doesn't appear to be much. I would say just not run as much timing and don't worry about the timing tricker. At frame 7759 you're showing 14.74 AFR and 31.5 degrees of timing. That's not really a good thing on nitrous.
07-27-2009, 12:40 AM
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I'm not 100% sure what has been done for airflow corrections becase the tune was done by a tuner and I have just been cleaning it up (while working on my own tune). I know the MAF calibration is different from stock.
07-27-2009, 12:56 AM
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You dont need to worry about the car running lean on decel. The engine isnt seeing any load, so youre not going to hurt anything. My Innovate wideband shows max lean with I am completely off the throttle on decel. Its nothing to worry about.
Its common to zero out your IAT VS Spark Retard table to a certain point. I forget exactly where mine is set, somewhere in the 120 range. After that, Im running stock retard. I figure if the IAT's are that bad, I dont need to be beating on the car anyway,.
Its common to zero out your IAT VS Spark Retard table to a certain point. I forget exactly where mine is set, somewhere in the 120 range. After that, Im running stock retard. I figure if the IAT's are that bad, I dont need to be beating on the car anyway,.
07-27-2009, 01:02 AM
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You dont need to worry about the car running lean on decel. The engine isnt seeing any load, so youre not going to hurt anything. My Innovate wideband shows max lean with I am completely off the throttle on decel. Its nothing to worry about.
Its common to zero out your IAT VS Spark Retard table to a certain point. I forget exactly where mine is set, somewhere in the 120 range. After that, Im running stock retard. I figure if the IAT's are that bad, I dont need to be beating on the car anyway,.
Its common to zero out your IAT VS Spark Retard table to a certain point. I forget exactly where mine is set, somewhere in the 120 range. After that, Im running stock retard. I figure if the IAT's are that bad, I dont need to be beating on the car anyway,.
it seems like I need to get this tune all sorted out before I spray any more nitrous though!
07-27-2009, 01:13 AM
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Is there anything from this $400 tune that I can keep? The tune seemed to be fine before I went back for the nitrous runs and he changed the MAF table a little and the IAT table. He changed the MAF table becasue he said that something made me run a little lean after adding a ported TB, nitrous plate, and changing up the CAI setup a bit.
07-27-2009, 12:04 PM
#19
Really, you should ask for your money back. It's a shitty half *** tune, but that's not an uncommon thing for a quick dyno tune.
It should only take a few hours to get all that stuff dialed in. There's no reason to keep any of it if it's not right. Maybe the fans settings you can leave.
It should only take a few hours to get all that stuff dialed in. There's no reason to keep any of it if it's not right. Maybe the fans settings you can leave.
07-27-2009, 09:58 PM
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Yeah, I would ask for my money back but he is the closest dyno within 2 hours to me and I don't want to not be able to use it. I'll just redo the tune myself and get it all cleaned up. Thanks man!
