WTF- Short Fuel Trim "Blip"?
06-07-2005, 01:55 PM
#1
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WTF- Short Fuel Trim "Blip"? I posted in the truck performance section...being a truck and all, but I definitely need you guy's opinions.
It feels like a tiny bump in the road...sorta like a miss. Anybody have experience with this? You'll notice that it seems only O2 B2 S1 seemed to have caught it. The other O2 seems to be unphased. Any ideas for getting to the root of this...or is this normal. I am in a fuel rich tune at the moment.
It feels like a tiny bump in the road...sorta like a miss. Anybody have experience with this? You'll notice that it seems only O2 B2 S1 seemed to have caught it. The other O2 seems to be unphased. Any ideas for getting to the root of this...or is this normal. I am in a fuel rich tune at the moment.
06-07-2005, 06:33 PM
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Finally! Somebody else who has this problem! WTF is it?! What have you done to your truck? My car does this, and I thought it was an isolated case. I have been watching this forum for months hoping somebody else would have this problem. Please PM me if you want to compare notes.
06-07-2005, 08:15 PM
#3
happens to me all the time, i get some -50's poping up on the computer, no idea what it is but i get it pretty frequently when im out tuning, every once in a while it will drop to -100 (maybe once every few drives or 2-3 times on longer drives)
never saw you post about it another user, or i would have said something too lol
never saw you post about it another user, or i would have said something too lol
06-07-2005, 08:26 PM
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Why! Why didn't somebody say something sooner? Geez. That would have saved me a ton of headaches. So what's up with it? It only happens with my MAF plugged in, but it happens with my friend's MAF on my car too. Is it the effect of the cam on the MAF? Which would not have the same effect in SD because you are running off MAP.
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06-07-2005, 08:47 PM
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Wow...pretty frustrating isn't it? My disclaimer first...very mechanical inclined but by no means a mechanic or even a tuner. I understand it all, just haven't had the time to attempt the learning curves of tuning...will some day soon enough. I work with someone else tuning for me, using my inputs and logs.
I haven't done MAFless tuning...interested...but again too busy. So nobody has experience of a fix or resolution. Seems I can't get it to do it under any WOT scenario. It rarely...I mean rarely does it under low throttle and VSS...mostly at 20% to 60% TPS and costant RPM ranges of 1800 to 3500. (I have a 2800 stall). Most of my MODs that count are in my sig...big enough cam...heads with big valves...plenty of breathing room...stock internals except rod bolts...and of course the SC. ANy ideas for different PID's might use to narrow the trouble shooting?
It definitely seems that it isn't an issue at WOT, but just seems something is wrong nevertheless.
I haven't done MAFless tuning...interested...but again too busy. So nobody has experience of a fix or resolution. Seems I can't get it to do it under any WOT scenario. It rarely...I mean rarely does it under low throttle and VSS...mostly at 20% to 60% TPS and costant RPM ranges of 1800 to 3500. (I have a 2800 stall). Most of my MODs that count are in my sig...big enough cam...heads with big valves...plenty of breathing room...stock internals except rod bolts...and of course the SC. ANy ideas for different PID's might use to narrow the trouble shooting?
It definitely seems that it isn't an issue at WOT, but just seems something is wrong nevertheless.
06-07-2005, 08:49 PM
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Originally Posted by Another_User
Finally! Somebody else who has this problem! WTF is it?! What have you done to your truck? My car does this, and I thought it was an isolated case. I have been watching this forum for months hoping somebody else would have this problem. Please PM me if you want to compare notes.
06-07-2005, 09:08 PM
#11
ok it looks like as a sudden change in map, there is a sudden dip in spark, then a sudden leanness, then a sudden fuel trim change. i am wondering if there is some sort of paramater saying if there is that rapid of a change and goes that low to cut out fuel, maybe its DFCO cutting in and out (if u have it on still) something that wants to pull lots of fuel, all of it.
how is your spark table, i have smoothed mine out and i dont recall seeing this ever since i did that actually, maybe there is just too big of a change in spark?
once we get something figured out in this can we try to shed some light on why i have other paramaters doing this?? its odd
how is your spark table, i have smoothed mine out and i dont recall seeing this ever since i did that actually, maybe there is just too big of a change in spark?
once we get something figured out in this can we try to shed some light on why i have other paramaters doing this?? its odd
06-08-2005, 06:54 PM
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Originally Posted by WS6FirebirdTA00
ok it looks like as a sudden change in map, there is a sudden dip in spark, then a sudden leanness, then a sudden fuel trim change. i am wondering if there is some sort of paramater saying if there is that rapid of a change and goes that low to cut out fuel, maybe its DFCO cutting in and out (if u have it on still) something that wants to pull lots of fuel, all of it.
how is your spark table, i have smoothed mine out and i dont recall seeing this ever since i did that actually, maybe there is just too big of a change in spark?
once we get something figured out in this can we try to shed some light on why i have other paramaters doing this?? its odd
how is your spark table, i have smoothed mine out and i dont recall seeing this ever since i did that actually, maybe there is just too big of a change in spark?
once we get something figured out in this can we try to shed some light on why i have other paramaters doing this?? its odd
06-09-2005, 06:17 AM
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Originally Posted by TT_Vert
probably just a dropped frame. mine will do this on occasion too. pretty much stock car.
Dave
Dave
06-09-2005, 07:30 PM
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If it dropped a frame, why would it just happen to drop an O2 sensor frame at the exact same time (or is just a big dip like you would expect when it starts yanking fuel like that), but none of the other frames like RPM, etc? Anybody got any logs of their car doing this so I can compare to mine? My e-mail is someoneelse@adelphia.net.
06-09-2005, 07:59 PM
#19
one that i am sending have 3 spots in it where it goes to -100, the other one i sent you to show you how my airflow values at idle drop out, the dynamic and idle desired, the DESIRED from the comptuer actually zeros out, maybe something to think about if the computer is doing it...