I have had the high idle issue myself. I am trying to remember how I corrected it. IIRC it had something to do with the IAC logic and having to change some faulty values.
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That's funny, I had the same problem with my '7427 in the camaro.....start up, idles good, put in gear and back to P/N and IAC/idle won't come back down, i think mine wouldn't go below 27 steps. I ended up switching to a Big Block bin to start, and all that went away, along with having a better spark map for my application.
Everytime you adjust the screw you have to have the key off for...? 10 seconds, then turn back on and ECM will calculate 0% TPS position, this is not based on TPS voltage, this is always an issue if someone has foot on gas when starting too. If you change TPS% at throttle closed to other then 0% nothing works right.
I did make the IAC adjustments for this? What is your elevation? It may be do to Baro adjustment...
Also could be a faulty IAC, I've done a couple in last year my self that had IAC counts but pintle was not moving. It's a gear drive that wears out/stripped. See if your IAC drives all the way closed by shorting A and B on ALDL port, turn key on, no start, walk around to IAC and unplug it. Start motor and should idle much lower, while not running you can look down IAC port from top of TBI and see pintle seated. Should be no air going through this port with pintle seated.
Yea i always leave the key off for awhile, I even leave it on for a little before starting it. I had the high idle after going to park problem with other bins too, the only time I didn't have it is when my spark wasn't advanced far, don't kno if that would lead to figuring it out. What do you use to make your spark tables they look nice and smooth. Anyway I can have the cammed lopey sounding idle with this tune also? I aint had much time to do the data tracing and stuff much yet. Im thinking about getting the Ostrich so I can do things more quicker and easier.
I saw the high idle in your other logs as well. Pretty sure it's not the bin, it's the same thing that drove me nuts on a vehicle, even after testing IAC and IAC wiring it still was happening. Replaced the IAC and it went away... month later same thing, different truck, replaced IAC and it went away. This time I tore apart the IAC to find it stripped in middle... Hope that's your issue.
There's a smooth tool in TunerPro, takes a little practice but works well, way easier to dial in issues and fuel VE tables when smooth.
You can get a lope with TBI at idle, have to run Open Loop Idle, then some playing with Idle RPM, fuel, spark idle bias etc... rev engine to dry out wet intake, test drive and see how it does when come to idle again. Have to keep the RPM up for cold starts, if you don't get it right it will load up after a couple minutes. Really a lot of work to make an EFI system run wrong and still run right off idle...
Yea ive heard the IAC are bad about getting stopped up atleast on some vehicles. being stripped would make since why it wouldnt go past 39 steps, with A and B jumped over I could hear it buzzing constantly like it wasnt moving in either direction. When comparing the 2 bins, I see several "Item Not Defined" could I be using the wrong version of XDF? Im using $42-1227747-V5.1
I will be running your bin as it does really good.
Did you have doubt? :thumbsup:
That is just a starter chip. If you read the thread we linked to earlier you'll find all the changes mentioned on how to start a chip for a built or big cam engine.
Your supposed to hear the buzzing when it seats all the ay and is still being forced there. The one's I had did seat! But still got stuck/stripped in middle?
When you see that it means there are changes to hex and that hex does not have a Parameter for it. In this case it is the ESC Done and Lean Cruise patch applied. ESC Done stops the forced knock test. DO NOT enable Lean Cruise until you have a near perfect tune!
I really love the high idle. After finding out I had some weak plugs I guess, I put new ones in. Im idling around 650-700 and it having the sound of a dragster or something but not quite as rough. Sometimes it wants to idle around 800-900. Ive tried alot of things and cant really get my IAC lower then 46 still. If I do diagnostic mode or play with park to drive steps subtracted I can see that the IAC will go to 0 so I know its working properly. Mabe theres something im missing in the bin.
Idle with this ECM is a real trick. First you need to know it will always idle higher in Park/Neutral. It will always IDle higher when not fully warmed up. IAC has full control in Drive and even more Closed Loop.
DO this, drive vehicle after fully warmed up and data reading or recording, when you pull in driveway or? leave it in Drive and look at IAC counts, where are they now? Should be around 10-20. Higher? Turn throttle blade screw in 1/4 turn with key off! Lower? Turn screw out 1/4 turn with key off. Test drive and do it again. Then forget them, they will always change, this is the only time you look at them.
Can also set "IAC - Max RPM hot Pk/N" to 900 to help to high an idle at other then Closed Loop in drive. And "IAC - Max Cold RPM in Kickdown Mode"
Yea. The first time I tried this it didnt change, it did now it just takes it awhile to figure it out and adjust. I got my IAC down to about 10-20. I turned it 1 round in from the factory setting after I was done, lol! Everytime I start it I think it has to take awhile to relearn? It will go closed loop and still stay at 39 steps for awhile until it starts to drop the IAC, could that be cause my tps?
You'll have to check TPS voltage with that big a movement in throttle blades. Should be .54 volts or close, may have to groove out bolt holes.
"IAC - Position vs Temp"
Drop this entire table by 10 and recheck.Quote:
This table sets the amount of bypass air vs. coolant temperature, thus controlling idle speed. This function is similar to the “fast idle” function of a carburetor. Control will transfer to the Target Idle RPM table after a set value of engine coolant has been reached.
IAC position vs coolant temperature (in steps). After the engine starts, the IAC is decayed from the park position to this position, with adjustments.
These adjustments can include: A/C on, baro, low battery. It is better to set the IAC position vs. coolant values a little on the low side. This allows the rpm to drop below the desired idle speed, to then be 'caught'. Otherwise, it seems as though the idle never drops down to where it should be.
Also "IAC - Throttle Follower Idle" can be reduced.
I got thisn done the other day. The IAC still wants to set at 39 until I trick it, I can pull pressure on my shifter without taking it out of park and it thinks it in drive, then the IAC will start to drop. Nothing seems to make the IAC drop after its started at normal temp, this is not a big prob for me tho. Kickdown steps ive heard should be less then the IAC position vs coolant table but its not, Position vs coolant is at 12 and the kickdown is at 25 tho reducing it dont seem to make a difference other then idling higher. how should kickdown be set?