Speed Density Tuning
05-03-2005, 12:35 AM
#23
Originally Posted by sardog46
Mark i could send you the tune i am running with right now and see how that works.
THAT would make his Auto run good
here is what I posted else where. Not as in depth as what I tried to post here but you will get the idea
Originally Posted by Ellis
My questions is simple. How are your cars idling? Seems to be a common problem with the Gen-III engine. Get the car to idle and it draggs you down the road. Get it to stop the "Cruise control" effect and it won't idle.
We got it working fairly good then when I installed the new ,smaller ,converter this weekend it all went to hell again.
Here is where we are at.
The car always starts right up when cold and idles to operating temp with very little surging as long as you do not put it in gear. If you try to put it in gear it will surge and die. Thie also happens if you shut the car off and restart is after a small wait like a drive through.
We have tried many different methodes to fix this and I was wondrering what every one else is doing?
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Ellis
We got it working fairly good then when I installed the new ,smaller ,converter this weekend it all went to hell again.
Here is where we are at.
The car always starts right up when cold and idles to operating temp with very little surging as long as you do not put it in gear. If you try to put it in gear it will surge and die. Thie also happens if you shut the car off and restart is after a small wait like a drive through.
We have tried many different methodes to fix this and I was wondrering what every one else is doing?
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Ellis
05-03-2005, 03:23 AM
#24
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Well, mine idles great with no "cruise control effect", so it can be done. Mine was extremely touchy as far as drilling the TB blade and adjusting the set screw to get a solid idle with no "cruise control" effect, and it took quite a bit of fiddling before I found the sweet spot.
You mention that it does okay until put in drive... How does the RAF table look for "In Gear" as opposed to "P/N"? Wait, hold on... I just downloaded Mark's tune from Horist's site. I know that quite a bit has probably been changed since this was uploaded, but is the RAF table still the same? The P/N RAF numbers look really low to me, even lower than stock. An aftermarket cam needs more airflow at idle than stock, which is of course why we drill the TB blade and adjust the set screw. The RAF table also needs to be adjusted upward from stock because of this increased need for air. I would also adjust the "In Gear" line of the RAF table to be a bit higher than the P/N line, since it seems to be having the most problems when put into gear. As more load is placed on the engine (i.e.- the tranny being put in gear) the RAF needs to be increased to compensate.
I'd start with adding 2 to all the cells in the "P/N" line of the RAF table, and adding 3 to all the cells in the "In Gear" line, and seeing if that has a positive effect.
Mark- Post up those LTIT's/STIT's/IAC counts, and let me know if upping the RAF table helps at all.
You mention that it does okay until put in drive... How does the RAF table look for "In Gear" as opposed to "P/N"? Wait, hold on... I just downloaded Mark's tune from Horist's site. I know that quite a bit has probably been changed since this was uploaded, but is the RAF table still the same? The P/N RAF numbers look really low to me, even lower than stock. An aftermarket cam needs more airflow at idle than stock, which is of course why we drill the TB blade and adjust the set screw. The RAF table also needs to be adjusted upward from stock because of this increased need for air. I would also adjust the "In Gear" line of the RAF table to be a bit higher than the P/N line, since it seems to be having the most problems when put into gear. As more load is placed on the engine (i.e.- the tranny being put in gear) the RAF needs to be increased to compensate.
I'd start with adding 2 to all the cells in the "P/N" line of the RAF table, and adding 3 to all the cells in the "In Gear" line, and seeing if that has a positive effect.
Mark- Post up those LTIT's/STIT's/IAC counts, and let me know if upping the RAF table helps at all.
05-03-2005, 08:00 AM
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Now I understand Ellis....that does **** you off huh? 
Lets see if I can fill in any detials here - without being able to give you my tune.
My car idled better with a big hole in the TB blade. But the crusie control effect was worse than it is now with a stock blade & the set screw turned way up. And the surging it's having now after SD tuning is due to the VE table being "correct" down low (or in the NW corner of the 3d chart). The car was very rich in that area, like pegged. Now the chart is blue in that area and it's reading -10. If I load the previous "bad" tune back in, it idles MUCH better!
And I'm sorry but I'm having a blonde moment here. What the Hell is RAF or LTIT? For some reason I'm drawing a blank this morning without being able to go into the tune & look at it. (R____ Air Flow, Long Term I____ Trims?)
Also Matt, you have an M6. The cruise control effect is reported mostly on A4 cars. I see several M6 car owners talking about just the opposite, where they push in the clutch & the rpms drop down into the mud until they come to a stop. If I put my car in neutral the rpms will stay above 1500 until the car slows to 5mph.
One more data point - when I load the previous tune in, I can crack the throttle, do whatever & the timing stays right where it is set. It doesn't drop 10* when the idle goes low on the rebound.
Interesting **** these PCM cars.....where the Hell is my 750 Holley & my dual point Accel?
Lets see if I can fill in any detials here - without being able to give you my tune.
My car idled better with a big hole in the TB blade. But the crusie control effect was worse than it is now with a stock blade & the set screw turned way up. And the surging it's having now after SD tuning is due to the VE table being "correct" down low (or in the NW corner of the 3d chart). The car was very rich in that area, like pegged. Now the chart is blue in that area and it's reading -10. If I load the previous "bad" tune back in, it idles MUCH better!
And I'm sorry but I'm having a blonde moment here. What the Hell is RAF or LTIT? For some reason I'm drawing a blank this morning without being able to go into the tune & look at it. (R____ Air Flow, Long Term I____ Trims?)
Also Matt, you have an M6. The cruise control effect is reported mostly on A4 cars. I see several M6 car owners talking about just the opposite, where they push in the clutch & the rpms drop down into the mud until they come to a stop. If I put my car in neutral the rpms will stay above 1500 until the car slows to 5mph.
One more data point - when I load the previous tune in, I can crack the throttle, do whatever & the timing stays right where it is set. It doesn't drop 10* when the idle goes low on the rebound.
Interesting **** these PCM cars.....where the Hell is my 750 Holley & my dual point Accel?
05-03-2005, 08:33 AM
#26
Stupid question, then again I am not useing HPT. What is RAF. If it is what I think it is "Idle Air Flow (Gm/sec) vs. Coolant Temp Vs Gear" I have added like 3 so far. This table and IAC Park table seem to have the biggest effects on Idle for me. I will have to go looking through HPT to see. The biggest help will be finging the MPH table
BTW I have found drilling the TB to be bad in the past and I know it can be done with the screw instead. Just my experiance nothing more. getting rid of the drilled blade on Marks helped alot.
BTW I have found drilling the TB to be bad in the past and I know it can be done with the screw instead. Just my experiance nothing more. getting rid of the drilled blade on Marks helped alot.
Last edited by TwoFast4Lv; 05-03-2005 at 08:39 AM.
05-03-2005, 03:18 PM
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Well, when it was bad, if I was moving above say 10 or 15 mph, if I pushed the clutch in, the RPM's would actually rev up to about 3500 and hang there until I came to a stop. If I left it in gear, it would accelerate without my foot on the gas. It was pretty wonky. This was when I had yet to drill the TB hole, and just had the set screw cranked down. Then I read that the TPS voltage needs to be under .6, and mine was way over that. Now, I have a conservative hole drilled in my TB, and I use the screw for fine tuning, which has worked pretty well. The screw alone just wasn't enough to adjust for a cam my size and still be under .6 TPS voltage.
RAF is Running Air Flow, and can be found in HPTuner under General>Engine>Idle>Idle Airflow. It's under the heading Base Running Airflow, and it's a button that says Idle Air Flow vs. ECT. It's got a line for "In Gear" and "P/N", and the data in the table is airmass in g/sec. This is one of the main tables that the IAC uses to find idle. It's basically how much airmass it wants to maintain going into the engine at idle. If it's too low, one of the classic symptoms is cam surge. One thing you can do, Mark, is inplug the IAC motor when the car is surging (try to do this while it's surging up). If it stops surging, you can pretty much bet that your RAF table is too low.
LTIT's and STIT's are long term and short term idle trims, and work alot like fuel trims. Just as LTFT's and STFT's indicate % of error for the VE table, LTIT's and STIT's indicate % of error for the RAF table. They are also PID's that can be logged in the scanner. Since your idle in park is fairly stable, I'd log LTIT PN/ACoff, Idle Adapt (STIT), and ECT with the car in park on a cold start. You idle trims will show as a +/- number just like fuel trims. They will show you how far off your P/N RAF line is. Make sure that you log LTIT and STIT with both the AC and cooling fans disabled, as when they turn on, the PCM adds airmass to the RAF table to compensate for the additional load placed on the engine.
Mark, I think you have it backwards. With your trims "pegged" in the red it was showing that the fueling was lean (not rich) so the PCM is adding in additional fuel. With a blue -10, it's showing that the fueling is rich, so the PCM is subtracting fuel. Leaning out the VE table in the idle area definitely helps eliminate surging. Get those trims closer to 0 (or slightly positive) and see what happens. You may find that you have to run the VE table a little lean down low to get it to hold a steady idle. Be careful- if you lean it out too much you'll start getting hesitation when accelerating.
RAF is Running Air Flow, and can be found in HPTuner under General>Engine>Idle>Idle Airflow. It's under the heading Base Running Airflow, and it's a button that says Idle Air Flow vs. ECT. It's got a line for "In Gear" and "P/N", and the data in the table is airmass in g/sec. This is one of the main tables that the IAC uses to find idle. It's basically how much airmass it wants to maintain going into the engine at idle. If it's too low, one of the classic symptoms is cam surge. One thing you can do, Mark, is inplug the IAC motor when the car is surging (try to do this while it's surging up). If it stops surging, you can pretty much bet that your RAF table is too low.
LTIT's and STIT's are long term and short term idle trims, and work alot like fuel trims. Just as LTFT's and STFT's indicate % of error for the VE table, LTIT's and STIT's indicate % of error for the RAF table. They are also PID's that can be logged in the scanner. Since your idle in park is fairly stable, I'd log LTIT PN/ACoff, Idle Adapt (STIT), and ECT with the car in park on a cold start. You idle trims will show as a +/- number just like fuel trims. They will show you how far off your P/N RAF line is. Make sure that you log LTIT and STIT with both the AC and cooling fans disabled, as when they turn on, the PCM adds airmass to the RAF table to compensate for the additional load placed on the engine.
Mark, I think you have it backwards. With your trims "pegged" in the red it was showing that the fueling was lean (not rich) so the PCM is adding in additional fuel. With a blue -10, it's showing that the fueling is rich, so the PCM is subtracting fuel. Leaning out the VE table in the idle area definitely helps eliminate surging. Get those trims closer to 0 (or slightly positive) and see what happens. You may find that you have to run the VE table a little lean down low to get it to hold a steady idle. Be careful- if you lean it out too much you'll start getting hesitation when accelerating.
05-03-2005, 10:12 PM
#29
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hey matt could you send me the tune you are using now for me to do some comarision?
sardog46@hotmail.com
sardog46@hotmail.com
05-03-2005, 10:42 PM
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Originally Posted by sardog46
hey matt could you send me the tune you are using now for me to do some comarision?
sardog46@hotmail.com
sardog46@hotmail.com
05-04-2005, 07:58 AM
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Thanks Matt! I will go look at that. Certainly sounds like the tables I was looking for. I was wondering how you adj for airflow after you install a cam. Thinking there would need to be something dynamic.....the stupid hole in the TB blade can't do everything.
And I was dyslexic....lean = red, rich = blue as far as the trims go. (unless of course I was thinking about the VE table, which IS the opposite)
And I was dyslexic....lean = red, rich = blue as far as the trims go. (unless of course I was thinking about the VE table, which IS the opposite)
05-04-2005, 08:08 AM
#32
Hey Mark I found some things last night. One is a killer right up and in effect is exactly what I was tring to do last night.
https://ls1tech.com/forums/pcm-diagnostics-tuning/267674-idle-transition-tuning.html
I saved it for future referance.
here is a link from the other place I was posting.
http://www.mgfracing.com/tunercat/viewtopic.php?t=91
Enjoy man!
BTW just went out side and checked. Car started Right up..I tossed it in gear and she did not die surged some but hung on till the surging quit. Now I can plot out the cold start in gear G/S!
ONE step closer!!
Thanks for the help! The more we work together the better it gets
https://ls1tech.com/forums/pcm-diagnostics-tuning/267674-idle-transition-tuning.html
I saved it for future referance.
here is a link from the other place I was posting.
http://www.mgfracing.com/tunercat/viewtopic.php?t=91
Enjoy man!
BTW just went out side and checked. Car started Right up..I tossed it in gear and she did not die
surged some but hung on till the surging quit. Now I can plot out the cold start in gear G/S!ONE step closer!!
Thanks for the help! The more we work together the better it gets
Last edited by TwoFast4Lv; 05-04-2005 at 08:25 AM.
05-08-2005, 12:43 AM
#34
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Originally Posted by TwoFast4Lv
I am tired of two things. First waiting my Dynojet to build my wide band and ships it and two LS1s that won't idle. the tunning section is full of them!
BTW do not feel bad. we have about 16 hours in this one on just base tune and Idle!
Ellis why don't you get an Innovate MotorSports WBO2 system instead of a DynoJet system?
05-15-2005, 11:58 AM
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I raised the RAF table yesterday by 20% caross the board & it seemed to help. Much less surging sitting in the garage. So I logged afile & drove to Monore. The car still surged badly when I came to a stop. I went in this morning to lok at the file & it's gone. Not sure what I did wrong.
So, shooting in the dark, I just raised the hot RAF cells up another 20%, and I raised the IAC table 10% down low & 20% up high. I will post the results later.
So, shooting in the dark, I just raised the hot RAF cells up another 20%, and I raised the IAC table 10% down low & 20% up high. I will post the results later.
05-15-2005, 12:32 PM
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Well, that seemed to help. I have about 10 seconds of mild surge about 30 sec after cold start & then it settles down. Nothing on hot start. Recovers fine after revving. The only issue I have now is when you are at sustained rpm & let off (simluated driving & coming to a stop) then it surges bad. Yesterday it went from wanting to die to trying to push me into the car in front of me. At the track it tried to die after my burnouts. I'm going to go see if I can find a table that looks like it might control that.....
05-15-2005, 02:16 PM
#38
Nice!
I have been playing with it on and off as i can. Only so many cold starts in a day
I have found bigg jumps hurt more then they help, and the damn Idle relearn will kill you! You can have it perfect but as the PCM slowly move towards what it thinks is perfect(the idle relearn) it goes away again
I had it nailed perfect and then tries to bring the in gear cruse issue down and screwed my self.
BTW The M6 files zero ALL the in gear cell's So they must have a switch to use one set of cells. which makes sence because the PCM can't tell when you are letting the clutch out like and Auto.
I Finally have my Wide band
I have been playing with it on and off as i can. Only so many cold starts in a day
I have found bigg jumps hurt more then they help, and the damn Idle relearn will kill you! You can have it perfect but as the PCM slowly move towards what it thinks is perfect(the idle relearn) it goes away again
I had it nailed perfect and then tries to bring the in gear cruse issue down and screwed my self.
BTW The M6 files zero ALL the in gear cell's
So they must have a switch to use one set of cells. which makes sence because the PCM can't tell when you are letting the clutch out like and Auto.I Finally have my Wide band
05-15-2005, 02:46 PM
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Wide band....that's a good thing. I saw where one guy posted in that thread you linked to saying he thought speed density tuning is a waste if you run a MAF normally. I was wondering about that, but I still think if you nail it SD wise, it 'should be' better.
Have you learned anything about the throttle decay or delay tables? I'm wondering if those are the ones that control how the car finds idle when you let off the gas.
Have you learned anything about the throttle decay or delay tables? I'm wondering if those are the ones that control how the car finds idle when you let off the gas.
05-15-2005, 06:03 PM
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I just tried raising the idle proprotional tables thinking it might make the PCM 'fix' the idle faster. Might have made it worse actually. So then while I was sitting there logging, I opened up the special control panel & when I raised the IAC Control Steps from 40 to 60, the problem went away. Although the idle went up to over 1000 rpm. And you can't control BOTH at the same time manually. Anyway, when I look in the IAC area of my tune the max airflow is set to 40. Could that be what I need to change? I'm going to go bump that to 60 & see what happens.
Well I'll be dipped in ****. Moving that up to 60, along with the RAF changes, seems to have helped a LOT. I'll drive the car later & make sure.
Well I'll be dipped in ****. Moving that up to 60, along with the RAF changes, seems to have helped a LOT. I'll drive the car later & make sure.
Last edited by WAHUSKER; 05-15-2005 at 06:12 PM.