using hp tuners installed a lq4 with 223 232 115 custom grind cam in my 06 Silverado has mp112 3.2 pulley runnin 5 to 6 lbs boost also had headers had exact same setup on my 4.8 but no cam everything runs great except a idle surge will sometimes get as bad as 300 to 1200 rpm supposed to be 750 ive searched a lot and tried a lot I'm not too experienced with tuning I did my 4l80e segmentswap and tuning myself and few other things I actually had a pro dyno tune this thing does great wot afr is 11.3 just the surging I had him try to fix it but no luck

 

This doesn't sound surprising. Almost anyone with a keyboard can change the few parameters needed to account for the engine size change while nailing down a dyno tune. The full availability of sensor feedback makes that portion of tuning a breeze. The idle is where you may have no ability to scan (seconds after start), limited ability to scan (engine not warmed up), or full ability to scan sensors at the bottom and least accurate portions of their range. MAFs are least accurate at low flow, MAPs give erratic readings due to flow fluctuations, and IATs get heat soaked from the surrounding engine bay's lack of airflow. To complicate matters, your idle is controlled by numerous spark, IAC, and expected airflow tables that can be markedly different than non-idle tables. Since you are learning to tune for yourself, scan every idle parameter you can, and see how they match up to the expected tables. Just make sure to always save a previous working tune. The great thing about idle tuning is that it is almost impossible to make a change that could cause any real damage, so you don't have the same pressure as you would taking a chance on an unknown change with WOT tuning.

 

yes exactly I usually don't tune myself like I said just small stuff mostly trans..segment swap small stuff I normally just pay the tuner if I made any changes and everythings perfect..problem is had diffrences with a really good tuner that I probably cant use so I had another well known local tuner dyno tune my new lq4 swap and dynode and runs great its just this idle surge ..if I start it up it will idle all day long no prob its when its in d or r that I sometimes have problems like id I smack the gas then give nothing like a quick roar it will some times stall or sometimes bounce from around 1300rpm to 400 rpm until brake or gas but dosent do it all the time so idk tuner tried to fix but of course cant kinda stuck rn wish my old tuner would take me back haha

 

heres my dyno tune..failed fix and some logs

 

I didn't spend too much time looking, but your base running airflow and throttle cracker tables both look like they need work. I used to have a file from tuning an LQ9 with a moderately larger cam than yours that I could reference, but it now resides with whomever stole that computer along with my original HPT cable.

 

damn sorry to hear that yeah somebody else said something about the idle ve table but I don't know how to fix it I'm not too familiar with how I obtain the right numbers go up go down or what

 

Try looking up similar tunes in the repository, then use HPT's compare function to look at the differences. Also look at stock tunes to see where the tables started. Just don't totally trust an unknown tune to be correct, even if you know the vehicle it came from runs good. This is because tuning can be accomplished by changing air or fueling, and sometimes people make up for bad injector data by changing airflow tables instead, or vice versa.

 

I appreciate that yeah I tried downloading some tunes but of course none of them work with my version of hptuners looks like I will have to upgrade and my setups not too common especially with a custom cam

 

Honestly at this Point I've had the tune changed so many times and it seems to make no difference I'm starting to wonder if it is something mechanical it's totally intermittent I can drive it for 10 minutes and not have it do it at all then I'll put it in reverse give it a little time and it will idle up and down up and down pulsing me backwards wanting to die unless I hit the brake or give it gas so far I've changed the plugs checked the brand new MSD wires and tried my best to take some carb cleaner and spray it around the supercharger and vacuum lines with no change in idle and all my grounds and electrical seem to be fine

 

In the scanner, use the switched part to increase and decrease idle air counts and ignition advance, it will make it easier to figure out which way to go. The last cammed 6.0 I tuned did the same thing until I added base idle air.

 

ok will do I've heard this is very common with a cam butt in your experience was it constantly doing that or sometimes it would sometimes it wouldn't because the intermittent part is what freaks me out

 

It would probably be better to just start over with a clean stock tune and go from there. That's what we do 99% of the time vs trying to tune behind someone else especially if you're fighting a bunch of issues.

 

I appreciate that but as of right now I'm looking into it possibly not being the tune I know I am in the tuning section so I don't know if I should move to a different category or you guys might be able to help me... so if I'm going through an intersection and I tap the gas hard but have to slow down on the other side it will possibly die or sometimes I'll be at the end of a court full cocked making a U-turn and then when I get to a low speed the idle will surge up and down until I either push the brake really hard give it gas or it stalls out same thing if I'm pulling up to a gas pump or need to throw it in reverse sometimes it will surge when I change the gears and either bounce around until I hit the gas brake or stall keep in mind sometimes it doesn't sometimes it does not and I have not noticed any type of pattern I don't know if it could be electrical or vacuum or what this truck never did it until I put the 6.0 with a cam in it so I naturally assumed it was the tune do two different motor and cam but may not be or could be

 

Power brake booster vacuum leak?

 

Add 1 g/sec across your base air flow table to see if it helps. Make sure you have the units correct before you change it. If it does help, add another .25 g/sec and see if it helps any more.

You'll also need to pull some fuel at idle with that cam. Highlight the 0-800 RPM section, between 20 kPA and 70 kPa and type in .80 and hit the multiply sign. Do this for the 1200 RPM line but only multiply by .9.

Open idle underspeed table. From 200 RPM up, add 8 degrees, and 12 degrees above 250 RPM.

Last, you might want to turn up your idle screw a bit on the throttle body to see if it helps. Anytime you make a change, unplug your TPS, turn the key on (don't start the car) and leave it on for about 10 seconds, then turn the key off and plug the TPS back in. It will reset the ECU to 0% TPS at whatever your new setting is.

Do these changes one at a time. They're not perfect or the best way of doing it, but I've installed similar sized cams in smaller engines and these changes made it idle great.

I just did a 226/232 on a 115 LSA in a 5.3 a few weeks ago. Idles at 750 RPM perfectly.

 

This was actually very helpful I will give it a shot tomorrow as far as adjustment screw mine is electronic throttle body so I don't think I have that? Also where would the throttle position sensor be on my truck is it on the throttle body?

 

It seems odd that the VE numbers have to be so high at an idle. The STFT numbers are pretty low though. That makes me suspect either the fuel injector data or the fuel pressure itself. I would start there. What injectors do you have? Have you check the fuel pressure? I would also target a little higher idle speed for now. 750 is a bit low for that cam. You might get it to idle there, but I wouldn't start there for sure.

 

Joe, I think this is an 06 model...so drive by wire TB.
The base air flow table is pretty high as it is, but it wouldn't hurt to try a little higher airflow number.

You're right...The VE numbers at an idle are pretty high in the 0-800 rpm area. Higher than stock, but the fuel trims are relatively low, so I wonder if the injectors aren't flowing as much as they should or if the fuel pressure is low?

 

I mean last time I checked maybe it was on the 4.8 fuel pressure was 55 - 58 and as far as injector data I got it directly from the manufacturer and they were fine in my 4.8

 

If hes running a 4.8 tune and switched to a 6.0, its possible that the entire VE table was scaled which would give the high VE numbers. The problem is that going from a stock cam 4.8 to a cammed 6.0, the VE tables shouldn't have been touched below 1200 RPM, and then tuned from there.