JekyllandHyde

iTrader: (3)

Ok, I just started diving back into trying to tune my car this past weekend. When I last left off, I had an idle surging problem. So, using sAUJP v4, I enabled open loop idle and decided to try and tune from there to get it steady at operating temp, and then give idle control back to the computer once it was "good enough" and play with closed loop from there. I did get a successful data log with the car idling steady at 800rpm at ~45-50kpa for 15 minutes. Couple of things I noticed that seemed a little odd, I was hoping somebody could tell me if I should be worrying about this:

1.) During the data log, the value "In MAP AE" kept coming up every few seconds. Is this normal at idle? The idle does surge ever so slightly, and when it does, this value kicks in. Would it help to reduce the dAE vs. MAP value?

2.) O2 readings were pegged at .035v, and very few crosscounts were happenning. Does this matter if I'm idling open loop? I tried giving it more fuel but it de-stabilized the idle. Should cross counts be happenning even if idling in Open loop? The O2 sensor is a brand new heated O2 sensor as well.

3.) Motor seems extremely responsive to the IAC. For instance, I have the IAC set up to give 2 steps when fans come on. The car will idle steady, and when the fans come on and the extra IAC is commanded, surging begins again and sorts itself out in about 10 seconds. Would changing the deadbands here help with this? Or is there something else I should be looking at as well?

I'm going to get an O2 bung welded in for a wideband in a couple of weeks, but that was the steadiest I got the car to idle since doing the engine work. Setup is an L98 with TPIS ZZ409 cam, Trickflow heads and SLP T-RAM intake.

lakeffect2

"Map AE" would not be normal. What acceleration are you doing that would need enrichment.. Surging? Tightening the range of IAC steps to limit them would likely be helpful.

Another point people misinterpret or don't fully grasp is that IDLE is not at a single point. It is within an area bounded by RPM and Kpa on both the fuel and spark charts of the calibration. In the real world it's +/- around a designated point, but not always at it.

I found that if I have steep slopes within that area of the calibration the engine will surge like crazy, as it continues to add/subtract fuel and spark continuously up and down those slopes. I've found that keeping the slopes minimal there, no gross changes in the idle areas of those two tables, helps immensely.

JekyllandHyde

iTrader: (3)

Thanks for the suggestions. Now it brings up the next question... what would cause the car to go into MAP AE at idle? If I read correctly, the dAE vs MAP would account for giving more fuel vs. difference in MAP, so should I lower these values? When the idle is steady, it'll idle at 45-50kpa at 750-800rpm. My VE and SA tables don't have steep slopes in this section. I'm going to try to play around with the IAC settings to get the idle to smoothen out some more and then give closed loop a crack at it.

Here's my lower VE table:



My spark table



There any improvements you think I should make? The setup is running 36lb injectors at 50psi fuel pressue (vac line off)

gta324

Zero out the idle spark adder tables, atlest until you have dialed in main SA and Ve table, then you could try activate them again.

I add 10 steps when my fan kick in, but I use big one
Also check the "BPW vs battery voltage" table, if the voltage dip when the fan comes in it can start to surge since it will add some mSec, this may need to be changed specially with big injectors....

lakeffect2

I actually see a few erratic spots in the fuel under 40 & 45 Kpa where they go up and down between 800-1000rpm, and also under 55kpa at 1ooo rpm makes a big jump from anything below it in either direction. It may not be significant, but might be worth smoothing out.

JekyllandHyde

iTrader: (3)

Thanks for the suggestions. My friend originally cut fuel down in those areas to account for the bigger cam. I pulled some plugs this morning after the motor was idled for 30 minutes with the VE table I posted above. The plugs were just put in last Sunday. They looked like they just came out of the box. No coloration at all. So I added some fuel and started up. The O2 sensor is now swinging with cross counts occurring. With the VE table above, I was getting no cross counts and the O2 sensor was pegged at .035mV. I had to back timing down to 23*. The car will surge while warming up and when warm and fans running, the idle stabilizes. Idled it this way for 30 minutes, then pulled plugs after work, still no color except a slight tan on the porcelain. I'm going to try adding a little more fuel and see what happens.

I noticed though that the IAC was at zero steps without the fans running and the car was still surging every so often. Since the plugs were clean as new, could this be an indicator of lean surge? Again, I'm idling in open loop for now, no fuel correction. Should I close the TB blades a bit to give the IAC a little more control?

Also, in your opinions, how low of an idle can I go with this cam? I was thinking of trying for 700. (It's at 800 now). TPIS ZZ409 cam. 287/287 adv duration, .555/.555 lift 112 LSA.

34blazer

everyone seems to have a hard time understanding the idle logic, including myself. what i did figure out was the logic uses the spark timing to finely control idle, thats why the timing is constantly jumping around. it doesnt matter if its OL or CL either. what cam are you using? *nevermind on the cam question*


when i swapped to a more aggressive cam, the idle would surge all the time. using suggestions posted above seemed to help but not by much, and nothing helped at cold startup. only thing that slowed the surging to a rolling idle was the IAC idle deadband. so i figured the IAC logic wasnt the main issue. i noticed in the datalogs that the timing was jumping around, most people think its a problem, as did i. so i zeroed out the IDLE SPARK ADV/RET tables and it made it worse, stalling became a huge issue. so i returned the tables to original values and added 4* into each table and the idle immediatley stabilized as soon as it was uploaded.

$.02 HTH

gta324

I always zero out the IDLE SPARK ADV/RET until I have tuned the main SA and VE tables and the throttleblades/IAC. Then I test to activate IDLE SPARK ADV/RET again to see if it help to make the Idle better. I many cases It doesnt matter.

Currently I'm tuning one 9.0:1 383cui 227/239 0,57x 114lobe cam

and one 10.5:1 383cui with a 242/250 cam 0,520 cam 110lobe cam
first start
http://www.youtube.com/watch?v=KHCL4-dwrIE&feature=plcp
another clip
http://www.youtube.com/watch?v=mnS0Xlg2czs

and none of them got better idle with IDLE SPARK ADV/RET activated.....

and none of them stalles out or surge or have a rolling idle....street cars

But every combo is diffrent, I just like to have the timing locked when dialing in fuel and spark at idle........

there is a long post here on thirdgen about "big cam and idle"

good luck....

lakeffect2

My cam is a 230/236 split pattern on a 400 block. It is not happy trying to idle at 700. I moved it up to 900 and it is much better.

JekyllandHyde

iTrader: (3)

Thanks for the suggestions. I can't wait to get home and try some of this stuff. I was looking at some datalogs today at lunch, and noticed that the IAC was moving back and forth really quickly. Almost as if the IAC was over/undershooting when trying to maintain idle and cause an oscillation.

Now I did read up more on Idle IAC deadbands, but are there other values that slow/limit the IAC movement? I have the deadbands set to 70 for both neutral and drive values. I have my TB blades open so that I have 5 IAC steps at warm idle with the fans running.

34blazer

if the timing cant maintain constant idle, the logic forces the IAC to move, which is why it seems delayed.

JekyllandHyde

iTrader: (3)

34 blazer, how did you come up with the 4* Spark correction value? When I got mine to idle decent warm, I put in 2* into the 100rpm and up values in the RPM error Spark advance tables. The idle settled down and the surge was greatly reduced. (I had it at zero before.) I'm going to try fooling around with the spark advance/retard error tables as more fuel at this point causes the idle to destabilize.

Did you also do 4* across the board for both the error advance and retard tables?

34blazer

so it helped then?

nothing cosmic, just trial and error. overall i had to add more than the initial 4*. idle is consistant at any AFR, im working on my Baro mult table so when i drive up the mountain the idle afr has been in the 11's and as lean as 20 while the idle stayed the same.

be aware that my running characteristics are probably much different than everyone else(ford). overall lighter rotating mass and manual trans, engine is more sensitive to fine tuning the idle. i had to play with it for a couple of months before i got a good grasp on the idle logic. once the error tables were where they are at now there was still a slight surge during colder start ups. i noticed that the timing wasnt fluctuating like it does when warm, was stuck at 18* during warmup. so i pulled timing from the idle vs closed throttle table and havent had an issue since. originally it was at 26 and now its at 24 iirc. what is your closed throttle vs timing set at now?

JekyllandHyde

iTrader: (3)

Yes, it did help. I was idling the car at 23* timing with more fuel. I'm tuning using the real time emulator in TunerProRT v5. The idle was surging with fans running, 5-7 steps IAC. I noticed that idle kept trying to fall causing the IAC to come on and overshoot, so I tried adding 2* to the idle error Spark advance tables only and the idle smoothed out much better. I was having a hunch that I could probably smooth this out a little more using the spark error tables. I'm going to try it some more after work.

My closed throttle timing setting is 23* now. Like you, I have a manual trans and I'm also running a lightweight flywheel and clutch setup so this car has been a complete b**** to tune at idle.

That's what I'm shooting for, a consistent idle regardless of AFR. I noticed that with the stock motor and stock programming, when I was adjusting fuel pressure, the car would run incredibly rich pouring black smoke out the pipes when I unplugged the vac line to the AFPR, yet idle stayed the same.

34blazer

awesome, adding more to the error tables should help do the trick.

RBob

iTrader: (1)

For a port injected set up the IAC should be higher. I shoot for 20 - 25 steps with no extra loads. It gives better air distribution in the manifold by coming through the IAC passages.

The low 5 - 10 steps is for TBI set ups. This is due to the injectors being above the throttle blades. Having the blades open further helps pull the fuel past them at idle.

RBob.

JekyllandHyde

iTrader: (3)

Thanks RBob, I will try that tonight when I get home. I'm running an SLP T-RAM setup on my car so I figure that the long runners won't run into the same air distribution problems that the Miniram guys do.

JekyllandHyde

iTrader: (3)

34blazer, RBob, if you guys ever make it out to NYC, I owe you guys a drink. I returned the rpm error spark advance/retard tables to stock and the idle immediately settled down at a steady 800. I even took the car down to 700rpms and the idle is rock steady with the IAC staying stable. It actually feels like stock! For the last 6 months I've been running around in circles trying to get this pig to idle right. I'm going to try idling it in closed loop in a little while. Now to do some REAL tuning. Thanks again!

34blazer

sweet. glad you figured it out!

JekyllandHyde

iTrader: (3)

Just a little update. I played around with closed loop and the motor warms up and settles in nicely into closed loop. I had the stock AUJP O2 constants in there and even though it was idling rich, idle stayed dead steady. I lowered the O2 constants by 100 mV and BLMs settled in at 128-132 which was perfect. There was still a smell of fuel in there and I think I can lean out the idle a little more, or that may be the overlap from the bigger cam. I also noticed that the cam idles at 45-50 Kpa so I must be getting awesome vacuum with this cam.

Cold start idle was also nice and stable. With rpm error spark tables zeroed out, warm up routine was all over the place. Now, it goes to 1100rpm as commanded and settles down to 750 as the motor warms up with little to no hick-ups.

I'm guessing that the reason why most guys zero out these tables and it works for them is because the auto cars have more rotating mass so it helps to stabilize idle. With my manual trans setup and lightweight flywheel/clutch, it is a lot more sensitive as 34blazer suggested.

34blazer

i think most people dont understand how the logic works, tbh. also, since my cam has alot of overlap i just raised the threshold for closed loop idle to keep it in open loop while at idle. im using a WBO2 and it idles at ~16:1, seems to be happy there with minimal fumes.

JP86SS

iTrader: (1)

having a ramp in the correction tables to do more correction if the error is high works and works well for me with the IAC sitting at 40 steps at idle.
Finally got a good 825 rpm idle with my 406 with 236/242 112 hyd roller.
I have them with no correction at small errors up to 4* at the higher error levels. O2 constants shifted by 65.
I've always tried to get sub 10 steps on the IAC at idle and never got it to like it. 30-40 seems to be the sweet spot for my combo anyway so it is good to hear RBob confirm higher steps are needed. I've always pushed for lower but it seemed to run out of adjustment range and surging would start. Thought I just was doing something else wrong to cause it.
Made it where it likes it and all is well

gta324

What intake do you have?
I tried yester day to open the blades to gain more steps but didnt matter since I have a HSR Also activate the SA Stabilazer but didnt make any real diffrence but will test some more today.

JP86SS

iTrader: (1)

HSR also, 30# injectors running 50 psi.
You'll need to close the TB more to get more steps at idle (IAC opens more)
It really needs to have enough open and close range to raise and lower the RPM on its own.
If the TB is open too much then the IAC has only a few steps open. This can make it impossible for the IAC to lower the rpm if needed.
As far as the stabilizer stuff, I just keep the range small for the "close enough" lower error levels but let it have room to work at the higher rpm errors. Otherwise SA will look erratic at idle with small error levels making big changes.

gta324

Well I had between 10-20steps at idle and increased it but didnt matter

Will play some more with ISS and take out some SA in 100/75rpm error, dont like to add so much since I already have 34deg at idle

JP86SS

iTrader: (1)

Sounds like you are where I used to be...
Too much SA needs more fuel and your "thinking" the added spark is smoothing it out when actually you are just covering for too much fuel.
Drop your fueling and timing down and try again at 25-28* to see if it will stabilize.Then reduce the fuel and spark a few more degrees.
I originally was at 32* to get mine running and was getting about 5-8 MPG at best (but it seemingly ran good)
Dropping it down to the 24-26* range now has me at around 15-18 MPG.
Sometimes you just "miss" the tune and end up too high overall.

I never thought it would actually run with 22-24* at idle but after looking at some other bins it appeareared I was just "off" from where I should be.
Went back and started over (for the umteenth time!)
Starting over is not a bad thing, makes you realize what is working and what doesn't. Keep good notes and only put back what worked.
The stuff you may assume needs changed could be what hurts you overall.
Right now mine idles at 55-57 Kpa at 24* 900 RPM cold to 800-825 warmed up, 2.0 BPW. (27-33 IAC steps) Gets ugly if I go any lower on rpm.

Highway running maintains at about 29* at 2400 RPM = 70 MPH @ 48-50 Kpa, 15% throttle, 48 IAC steps, 2.40 BPW, calculated 18 MPG.
I will be going higher with the SA and leaning it out with HW mode as I progress with tuning, just thought the info might help you sort it out overall.

JP86SS

iTrader: (1)

My error tables RPM currently
They keep the timing around 2-3* variance with RPM moving less than 100 rpm

JekyllandHyde

iTrader: (3)

I agree with JP. I'm idling at 25*at idle and my VE is kind of flat in that area. I used to idle it at 28*. My spark error values are stock AUJP. My idle timing really jumps around. Anywhere from 15* to 29*. However, it idles like a stock cam at 700 with no fluctuations (just hear the sound of lope) so I'm going to keep it this way for awhile while I sort out the rest of the tune. In closed loop, I noticed a lot less fuel smell. Overall, its idling so well I don't want to touch it.

gta324

Well, I gained 5-10kpa from going from 30 to 34deg on idle. right now idles is around 60-65kPa in (N). My idle is actually ok, just like to test and tune for the better so will give it a try, even if i know my kPa will increase My BPW is around 0.9mSec.

29 deg at cruise, forget it atleast on my engine it needs timing to go smooth and dont light up my headers , but once again I will try a lower value just to try it, its so easy with a emulator
I cruise at 44-46deg and 1.2mSec. Recently I had 4degress lower and had 1400deg EGT now with higher SA Im at 1300deg..........

Well that the damn downside of tuning by yourself, it will never ends.........

oh, I only have 8.8:1 in comp.......