More Idle Tuning and IAC Count Adjustment

In this video I continue working with HP Tuners on the idle tuning issue I am having after the cam swap (if the engine is cold it dies when I shift it into gear.)
To solve it, I use HP Tuners to lower the Base Running Airflow numbers in the colder portion of the in gear table.
I also adjust the set screw on the throttle blades and do a TPS sensor relearn to get my IAC counts where they should be (around 60.)
Here's a link to the Goat Rope Garage channel I mention in the video, a big thanks to Kyle for his input on the issue: / @goatropegarage
Here's a link to the Evans Performance Academy site I mention in the video: evansperformanceacademy.vhx.tv/
Here's a link to the ERM Performance site I mention in the video. As I mentioned Ed Mowton has unfortunately passed away but you can still buy the training course from his son here: ermperformancetuning.com

[@marcocortez8923]

Watched your videos last night and got my swap running this morning. You’re the man ! New subscriber

[@pomonastilo]

I'd like to thank you for making your videos they have helped me out a lot I just started tuning last week on my build and your videos been very helpful

[@LowbuckLS]

pomonastilo awesome, glad you’re finding the videos helpful

[@cliffweatherbee6914]

The last 5 mins or so was the correct way to make the IAC changes. If you're having too high of a voltage count, you can drill a hole in the throttle blade.

[@joejoesmojo32]

Thx for the excellent video on this process Randy!

[@BowerRyan]

I have a 99 with a Corvette 02-04 stock cam in it shorty headers, all arp bolts etc I have been having the hardest time getting it to start the first try I’m going to try to turn up my tps like you to around 4 and see where I am at. Thank you for the videos. ✊🏼

[@kellylogan5557]

Yes I like the idle much better you want that cam sound everybody loves

[@Justls1v8parts]

Thanks for the detailed video

[@harryjohnson2]

Awesome video Lowbuck!

[@LowbuckLS]

Harry Johnson thanks sir

[@javierrios8751]

Live this vid, much appreciated

[@Go69]

at 39:09 you can now see why you must disable LTIT's when doing the config.. It's easier to get a more accurate look at the STIT when the LTIT is removed from the equation. When LTIT is turned OFF, you will only have to look at the STIT to see what the correction is, and the corrected # will populate in the graph. Before you got off into idle tuning... How close is your VE table in the idle areas? If fueling is off in the VE table.... you are going to be doing ALL of the idle tuning again after you make corrections to the VE table, or even the MAF table. For idle tuning, simply get the engine to a point where it will idle on it's own... DO NOT try and get it perfect.. Just to a point where it will idle. Then tune the MAF (if you have, or are running, one), then tune speed density (VE table), then when all of that is done... You can go back and polish the idle tables LAST.. Remember, if you polish idle tables FIRST, any change you make to VE table/speed density, or MAF, will require that you go back and re-do ALL OF YOUR IDLE TUNING WORK. All of these systems go hand in hand. You have to remember that or you will end up spending a lot of time redoing stuff each, and every, time you make a change to one of the other systems. I like to do MAF first. VE/Speed density second. Polish idle areas, RAF, IAC tables, IAC counts, LAST... On cam swaps, when I have no idea what it's going to take to get it started and idling, I'll leave the RAF #'s all factory, highlight the entire table, and multiply by 1.10 (adds 10% across the board) and then fire the motor while scanning with the IDLE CONFIG running in my scanner.. Even if the engine only runs for a couple seconds, it will usually pop a # in the temp field for IDLE AIRFLOW which I can then go back into the tune, burn the # in to the appropriate temp field, extrapolate over the other temp fields. This works most of the time depending on how large the cam is, and how far off the factory RAF #'s are from what the engine now needs. Good video.. But MAF and VE should ALWAYS be done first.. Maybe you did that and I missed those videos.

[@LowbuckLS]

Go69 I don’t have a MAF sensor as I am running the 3 bar Enhanced OS which is speed density only. I did have my VE table dialed in as best I could before starting this process. Thanks again for your advice.

[@mylesr5831]

Thanks for the info.

[@dextteraney]

Keep it up you are my only resource ✌

[@LowbuckLS]

Dextteraney thanks for watching and commenting, glad you’re finding the videos helpful.

[@TunedbyMMT]

No need to drill the tb! Now you got the iac where it should be. Adjust your base running airflow accordingly. Don’t forget to get the fueling taking care of as well. Lower the idle timing a bit too.

[@Go69]

Your TPS voltage should be .65V or less, and your % should be at 0. You can reset the % by unplugging the TPS, turning the key to the "RUN" position for 10 seconds, and then turning off the key and reconnecting the TPS. However, to get the voltage correct, you will either have to enlarge the hole in the throttle body (MINIMALLY!!!!! and NOT recommended!), or drill the TPS mounting screw holes larger, or SLOT the screw holes so that the TPS voltage can be brought back down by rotating the TPS now that the throttle blade is opened up further. Incrementally drilling the throttle blade larger is probably the better way to do this as then you do not have to drill, or slot, the TPS. However, it's too easy to drill the factory hole too large, which then creates many more problems. If you are drilling, I find it's easier to drill a new, smaller hole, closer to the original hole. Start with something like .050", put the TB back on, check your TPS %, and voltage, and IAC counts at HOT idle in gear... Yes, it may take several attempts to get right but it's easier to creep up on the correct throttle body blade position when you start with a new, smaller, hole that you can continue to enlarge until you hit the magic spot. Or course all of this that I typed applies ONLY to CABLE STYLE TB's!

[@j.t.hawthorne2832]

But what you missed.. is the top of the instructions you show on HP it’s says “a cammed car should be between 60-70 volts.. so you were golden!

[@wademunyard9026]

I tune the idle different. I don’t like adjusting the throttle stop screw because the pcm needs to enter an idle condition and won’t if the tps reading is too high. Instead I go along the same path they did stock. There’s a 4mm hole in the throttle blade which allows just enough air in at idle and than the iac and iac settings are there to slightly help and adjust accordingly. Iac is really slow at reacting so it’s only really a helper the way I see it. Igniting timing is much faster to react to idle changes. So if I see that the iac valve is struggling and pretty much wide open than I know it can’t really do it’s job. So I’ll slowly increase the throttle body hole size bringing the iac steps backs down to say 60. I’ve found by doing this I don’t really need to adjust all that much of the settings with idle. Obviously I’ll add a little idle air and rpm but the rest is pretty much spot on

[@codycole8]

awesome video!!

[@LowbuckLS]

cody cole thanks, glad you found it helpful

[@garagebuilt4290]

Hey buddy I believe the reason you slot the tps and keep it in that range is because the tps has a stop. If you go to much you can damage the sensor because it will brake that stop and go out of a readable range. Not real sure how much is to much but that's one of the reasons for slotting it. The old 3.8l engins use to come with a slotted tps I wonder if they would work on the ls throttle bodys. Surely someone would of thought of that by now though.

[@travishandlin3288]

Im new to hp but trying to learn. How did you get the tps volts to show on the grafts like that. Mine has the tps % but not the volts.

[@thomasjohnson1142]

Hey brother it’s been a while I hope your doing good I got a customer I’m tuning it’s considered old to me lol I’ve done a hand full of the Jen 3 but cable just a few but I have it idling great but when you put it in gear it’s like cruise control it wants to catch speed is that the throttle cracked ? Or iac I was told the iac is just for idle but I’m showing 155 iac when I’m gear with no throttle ?

[@carlclark7529]

When you started the truck at around the 21 minute mark could the initial raf number have been so high because your iac was pegged? I think it thought it wanted more air because it couldn’t get what it needed. Had the throttle blade and iac numbers been closer, I think the initial number of like 36-40 would definitely have been lower. I’m actually watching your video right now because I have the same exact problem with the stalling when put in gear at any engine temp.

[@michaelslack6891]

Should the rpm be higher for in gear versus park/neutral? Thanks for your time and knowledge! Mike in DFW

[@Tilly483]

do you have a video on setting up the VE histogram that you use I have been following you for a year or so is it possible to get a compiler file of your truck

[@exploringgodscountry]

I am trying to figure out how to tune for idle. I have a startup issue once engine is at operating temperature 200F. I think the table you are fiddling with Airflow vrs coolant temp may help me. Curious, why don't you adjust the setscrew on the throttle body then keep the IAC steps a bit lower so you don't max them out? Do you have a drive by wire throttle body? Haven't watched whole thing yet....

[@The72Z28]

Where's the link to the video that shows how you added the graft to record /log the idle desired air flow

[@nicksaveka5078]

My mechanic adjusted the idle screw cause my revs were quite high. Now it seems to cut out when my revs are really low. I want to adjust that idle screw so I can stop my engine from cutting out !! I have LS1 Holden Ute ss Vu

[@lsxjunkie]

Great video man, does ERM offer a book or pdf? I know Ed has passed, but I couldn't find such on the website. Thanks enjoy your videos

[@LowbuckLS]

It doesn't look like they offer the training course by itself anymore, it was a collection of pdfs, powerpoints and excel spreadsheets. Looks like you can still get it as part of a package with HP Tuners. Looks like the company has been sold to someone else.

[@lsxjunkie]

@@LowbuckLS I tried yesterday to MAF tune my bothers HCI WS6 and when I disabled LTFTs, closed loop, And dynamic fueling the car would not idle until I allowed the dynamic fueling back

[@jasonhaha42]

Where are you located I need someone to set my IAC i have had it tuned by a guy 3 times and it idles like crap and dies when i slow down Im in the DFW area. Thanks

[@mothridith9760]

you can pull the e brake one click and shut the day time running lights off

[@johncrankshaft2886]

There is a resistor you can plug inyo the sensor on the dash which makes the lights manual. Did this years ago

[@HeadFlowInc]

The issue is many tuners struggle when idle tuning the DBC throttle body in a normal idle range of 600-800 rpm range. Higher idles in the 900-1100 rpms are more forgiving. I was never able to get my 4.8 w 216/220 cam to recover idle with the IAC count between 40-60, My setup will only recover idle from revving and going into gear set at 0-1 count. I had to add idle bypass air manually at the throttle blade due to the IAC valve not being fast enough to stabilize the idle. What gets overlooked when tuning the DBC setup are things like Throttle Cracker and Throttle Follower etc. they don't exist without the electric motor control of a DBW. I fought with my idle off/on 6 months trying to follow the KZbin idle tuning videos. JD

[@LowbuckLS]

Yeah it seems like the Gen 3 LS based engines are tricky to get the idle dialed in. I need to learn more about the Throttle Cracker and Throttle Follower.

[@robertchambliss4098]

you sure that extra voltage was not from the charger being on your battery ?

[@miracleandsons]

Hello I have a gen v l83 Silverado with stage two tsp cam 218/226 635/635 lift 112 lsa. Would you be able to tell me what I could do with my hp tuning software to help it run better? It’s running sluggish at Lower Rpms and when warmed up

[@LowbuckLS]

Miracle Performance & Tuning I’d log the ignition timing and see what it’s at when it’s running sluggish, maybe one of the spark modifier tables is pulling ignition timing

[@miracleandsons]

Lowbuck LS I ran a log when it was sluggish the other day. Would you mind to take a look at it if I emailed it to you?

[@ktcarroll4723]

Hey man I have a issue maybe you can lead me what to look for gen3 5.3 2000 cam swap after warm up and I turn off truck it cranks and revs to 2500-3500 rpm for 3-5 seconds but I turn it off before it blows up I did the idle relearn disabled the throttle cracker lowered timing at start up etc etc and still the same thing plus the idle hangs and is like cruise control sometimes I have the mvpvi2 the truck runs good cruising plenty of power etc just this idling and start up flare 😓😓😓😓

[@LowbuckLS]

Kt Carroll I’d look at your startup idle airflow and see if it’s adding a bunch of air during cranking, you can log it like I did in this video: kzbin.info/www/bejne/rprUfq2cotR1fJI

[@michaelbaskinmichael9862]

Mine is so bad can’t hardly stop idles fine in park but in gear might go to 3000 rpm can help

[@driftworx4148]

Are you using hp tuner pro?

[@LowbuckLS]

No I'm just using an old school HP Tuners MVPI, the basic model with no analog inputs or anything. Looking to try the new MVPI soon though.

[@Go69]

Several things stand out.. Do you have LTFT turned OFF while you are doing the Idle config? If not, go back and do that BEFORE you start the idle config. Also, all adaptive idle airflow tables must be zeroed out while you are doing the config. HP TUNERS>ENGINE>IDLE>AIRFLOW>ADAPTIVE IDLE AIRFLOW>MAX IN GEAR/ACOFF, MIN IN GEAR/ACOFF MAX PN.AC/OFF MIN PN AC/OFF, AC OFFSET IN GEAR & P/N. All of those fields need to be zeroed out while you do the idle config. If you have electric fans, they need to be disabled for the idle config. Also, when you "CONNECT TO VEHICLE" in your scanner, and BEFORE you start logging, you need to click on the *CONTROLS* tab, click on *FUEL* and then click on the RESET LTFT tab... Even after doing everything correctly, you will still have to log several dead-cold starts to get the data correct. If you watch while it logs you will see that the numbers in each temperature field (especially the colder areas) will still be adjusting while the temp is rising, and the scanner will move to the next higher temp field, before the final # is populated. In short, the temp will move through the temp fields more quickly than the STIT can adapt and show the correct #(when the #'s are too far off). This is why you must do this log MULTIPLE days in a row from a dead cold start. Each day the #'s from the previous day will be closer, and closer, and then you should have enough time in each temperature field for the scanner to catch the correct # before the engine temp moves to the next field.

[@LowbuckLS]

Thanks for that information, I guess I didn't fully understand how the short term and long term trims worked, I'll give your method a try, thanks for the advice. Still learning as I go.

[@hajrudinkavazovic2231]

ECM need time to relearn all that specially on cold start

[@Go69]

@@hajrudinkavazovic2231 The entire purpose of "tuning" is to get the tables as close as possible so that the PCM (ECM?) does not NEED to make corrections. If your BRAF was spot on perfect at all times, then the idle trims will show ZERO correction or NO RELEARNING NECESSARY.. You can get it "close enough" so that the PCM can fix your incorrect data.. Aside from that, and specifically to your post, the only "learning" that you PCM is doing is MAKING ADJUSTMENTS IN YOUR POOR TUNE... Think about that.. The ONLY adjustments the PCM is making... is to compensate for YOUR tuning errors or incorrect data in the tables. Why not get them as close as possible so the PCM does not need to learn/relearn data? If your tune is so far off that the PCM has to make corrections to have the engine run properly, and you disconnect the battery, or otherwise lose memory... Your PCM will have to start that "learn" process all over and your car will run like DO DO on the first start after having lost the memory. Cars from the factory DO NOT have this problem, and neither should yours WHEN you have it tuned properly with all the tables CORRECT. See how that works?

[@jeremysparks4570]

Press the dome override about 4 times fast all running lights off..

[@austinsaucedo223]

What about a high idle? I changed spark plugs and wires bc of misfire but that went away it chops but sometimes it high idles at 2k rpm and sometimes 1300k rpm

[@mrsteal334]

hey bro, idk if you’ll reply or not, but my silverado has the same issue, it idles at around 2k rpm, sounds like it giving it gas, wanted to know if you got yours back to normal

[@austinsaucedo223]

@@mrsteal334 that truck I had was a built nitrous 5.3 bored to a 5.7 “ls1” but I had been abusing it obviously and I blew cylinder 8 spark plug right out the threads

[@austinsaucedo223]

@@mrsteal334 drove around on 7 cylinders after that for a month before it blew up I just hammered the cylinder 8 spark plug in the whole, was young and dumb and didn’t know about spark plug rethreaders

[@Keeterbob]

Could you have done this tuning with PCMhammer?

[@LowbuckLS]

You could use PCM Hammer in conjunction with TunerPro or Universal Patcher to do this. I plan on making some videos soon on using these tools for tuning.

[@ericharmer]

Ya saved my bacon with a client!

[@LowbuckLS]

Eric Harmer glad to hear it was helpful

[@brandonpylant9349]

You ever get the idle figured out on the truck

[@LowbuckLS]

Yep it's working good now, just had to reduce the base idle airflow at the colder temperatures by a bit, works great now.

[@brandonpylant9349]

Thanx for your videos man you do good at explaining everything. I enjoy keeping up with the progress of your truck

[@LowbuckLS]

@@brandonpylant9349 your welcome, glad you're finding the videos helpful.

[@MrJDRACING]

i zero the map out and after runs in the scan and use them number in the map after for both idle and drive sometime you have to increase it a few percent the number you got from the scan you have to play whit the trottle a bit to keep it going but that works great for me

[@jagunn1972]

not a good idea on the charger . it can cause issues. If u go to your headlight switch and press your dome light little round button a few times the headlights will turn off!!!!

[@justinrogers94]

so I can my tps down to 0 and my volts at .75 but now my iac is at 0... how do I fix that?

[@justinrogers94]

and im not getting 100% throttle only 98

[@theKEVman011]

First comment

[@BucketList22]

See that wasn’t hard, now that you got the first one behind you they will be a lot easier from here on out! 😉