Peterson70

First off, let me state that I am a total newb on tuning and such so please bare with me. I've done a lot of searching on hptuners forum and on here and still not figuring out what I need to do as far as getting the car to idle so I can do the proper filling procedures for the trans and bleeding out the cooling system.

I have been able to fire the car but not without the help of giving it some throttle to keep running. As soon as I let off the car dies. Before heads/cam all the trans work and stall converter, the car ran fine and was dyno tuned. My tuner is unavailable for a few weeks so taking the car to him is out of question right now.
I need advice/help on the things that need to be changed for the heads and cam swap to get it to idle. Car has stock MAF and stock injectors right now. I do have gtp injectors but don't know how to update the IFR table for those injectors. The scan shows that all STFT and LTFT's are at zero and not fluctuating when the vehicle is started.

Upgrades to engine:

Tick Performance SNS Stage 3 standard lobe cam (235/243, .630/.610 111+2)
Texas Speed PRC stage 2.5 CNC ported 241 heads (2.02 exh./1.575 int. Valves)
BTR .660 Vavle Springs and retainers
LS2 Chain
Tick Performance ported LS6 oil pump
Comp rocker trunion upgrade
GTP Injectors(still need installed and tuned in)

Upgrades already on car before Heads/Cam swap:

LS6 intake
TSP 1 7/8 LT's
SLP Lid

Upgrades to trans:

Billet super hold 2nd/4th servo
Alto red clutches(full rebuild)
Sonnax high-rev spring kits
Sonnax input drum sleeve
Sonnax .500 boost valve
Sonnax Pinless Accumulators
Kevlar wide band
Yank ss3600 stall converter

Like stated I'm a total newb to tuning. I have no clue where to start on this so please take it easy on me.

Naptown Dave

This write up helped me quite a bit
www.masterenginetuner.com/ls-big-cam-idle.html
I bet you will have to change your injectors, but not to get it to idle and run easy.
Don't hit it hard until you get it tuned, most likely you will go lean under hard acceleration and that makes bad things happen

Chevy406

iTrader: (12)

Idle >Airflow > Base Running Airflow > Idle Airflow
multiply the whole table by 1.2
Idle >RPM > Base Idle RPM > Target Idle Speed
bump idle rpm to 900 or 950

This should help the engine keep running. If not try turning the throttle stop screw a half turn but you need to scan and make sure the TPS still shows 0%. Do a TPS relearn if it doesn't show 0%.

JakeFusion

iTrader: (7)

Disable the MAF - see the HPT help site for how to disable MAF to tune in SD.

Once done, take your VE table... multiply the 400 by .6, the 800 by .8, and the 1200 column by .9. Then select all out to 2000 and smooth it. Change your idle to 1100 in the colder cells stepping down to 950 at 150+ degrees. Change your timing to about 25 degrees in the idle table. Save that file and upload it.

Check your idle. With HPT, bi-directional controls, lean it out from 14.7 to 15.2 or so and keep going til the idle stabalizes and it starts to chop. If that number is 15.8 in the bi-directional controls, divide it into 14.7... 14.7/15.8 is .93. Multiply your 800 and 1200 columns by that number (.93), save and reflash. You should be idling around 15.5:1 at that point and the cam should like that. You don't even need your wideband. Watch your narrowbands. When they are under 100mv... down to 30-50mv, you're lean enough. The sound also gives it away. You can also add timing... 26-28 may be ideal. Add timing until the kPa readings drop to 65-70 with that cam. Then back off a degree or two. That'll give you the "smoothest" and strongest idle.

Works on every big cam I've tuned. Takes literally about 2 mins to dial in the idle enough that you can start tuning... but first wait until the next day.

Next day after the car has cooled off, restart it and put it in gear but don't drive it or touch the gas (also disable the fans in bi-directional controls - you don't want airflow adders). In fact, go ahead and zero out all your adaptive airflow tables as well. Use the stock imperial HPT cfg. Let it warm all the way up. Take the base airflow numbers in the histogram and update the Base Running Airflow table in idle. Reflash (putting the stock adaptive airflow numbers back in). Then check and see if your mv for the O2s changed significantly since you changed the airflow model. You may need to mess with the bi-directional controls again, but it will be close.

If the throttle response is a little less than ideal, add 2% fuel to the 1200 column. Then you can start really tuning the VE table. Add about 6 degrees across the High Octane Timing table and copy to the Low table. Just drive it around with the wideband or you can use the narrowbands. Don't get into PE mode. Just drive around keeping it near 14.7:1. Update. Drive. Update. Do that 4-5 times and the VE will be dialed in pretty close below 4k RPM. You'll be able to drive to tuner and get WOT dialed in. MAF can be dialed in on the street as well using the same method.

I also have the data on the GTP injectors. It's from the ASA racing team, so it's the best injector data for them. It includes the transient table changes as well. I'll get for you tonight when I'm home.

70caminoman

Don't Mean to steal the thread but I am also going to be diving into this actually this weekend with my wife's car, and JakeFusion this looks to be a great way to get the car dialed in, idling and cruising very quickly.

I am struggling with one part that you are referring to "bir directional fuel controls" I can't seem to find this in any of the menus. I am using V2.24. I don't know if that helps, am I supposed to be looking in the scanner or using the real time tuning? I also just wanted to say I haven't connected to the car yet, because I'm buttoning the rest of it back up. I'm just trying to familiarize myself with the menus while I'm at work to save some time.

Thanks again,
Eliot

JakeFusion

iTrader: (7)

It's in the scanner. Under Display. Then it gives you VCM Controls > Fuel & Spark. You'll see the AFR rating. Turn it on and adjust. But adjust like .3 or so at a time and wait 3-5 secs for the motor to catch up.

70caminoman

Jake, Ok I think I understand what needs to be done for the base idle airflow table and to get to that point. I have a couple of questions prior to moving into tuning the VE table;

• when driving around to get theVE histogram, do you shoot for 20-40 hits in each cell below 4k RPM? How many are you looking for?
• when doing your logging for the histogram are you still commanding 14.7AFR using the bidirectional controls? Is this method accurate?
• also when you add 6 degrees of timing to the high octane table, do you really add it across the board? I understand shooting for more at idle to help stability and keep good throttle response, but this motor is 11.5:1 and its a fresh never fired build. I don't want to hurt anything.

Thanks again,
Eliot

JakeFusion

iTrader: (7)

VE table... yeah try to get as many cell hits as you can. Then when you paste special, do the multiply by. After doing that a couple of times, you do by half multiply as the changes should become smaller and smaller.

For VE tuning, don't command 14.7. The PCM commands what it needs. You're trying to see how far off from that command you are. The histogram then gives you the "change" needed in the VE table to achieve the desired A/F.

6 degrees in the idle regions. Keep the WOT timing stock for now.

Also, one thing I've been playing with... keep an eye on your airmass timing values on decel. Log airmass if you aren't. Then when you review your log, see if the car is unloading properly (.20g/sec and less) and reduce timing there below your idle timing (around 25-28 degrees for that cam - reduce to 22 degrees when you let off the gas). That will get it driving well. Copy those values into your idle table too, because it appears on decel, it blends the two tables.

70caminoman

Jake so when log airmass and and review the timing values at these 0.2g/cyl and less. Do I want to pull timing all the way across the timing values, for say at high rpms and let out, I immediately command lower timing to get it engine down to idle better? Or from say 3-4k rpm and below?

JakeFusion

iTrader: (7)

I'll have to get you a picture when I get home.

It would be under 2400rpm. Anywhere that you let off the gas in a cruise situation. So maybe 2000 and under.

70caminoman

Jake I'm still having trouble with this. the bi directional controls help it idle well and I can get the mv on my 02's down close to 100mv. but when I multiply the VE table in the 800 & 1200 column by that value it has trouble starting back up without me giving it gas

joecar

Try some different values in those VE cells until it stars and idles.

joecar

I don't know why you'd want to do this (did I miss something earlier in this thread...?)...?

statesman

It was in Jake's tuning guide in post #4 of this thread.

JakeFusion

iTrader: (7)

You'll be lean with the narrowbands that low, which is what you want with a cam with any overlap.

So when you adjust the A/F with the bidirectional controls, it idles? What's the value? 15.3? 15.5? See what cells your car is idling at in the 800 RPM cells (and maybe 1200 if it touches them). You can do that by loading the histogram, going to the VE table (if using default imperial), and watching what cells populate when you run your mouse across the the graph. See where it is idling.

Then take that number 14.7/15.5 let's say (.94), and multiply the values in those 2-3 cells it hits on idle by that number in the VE table. Save, reload, and refire.

If you still need to throttle it, you need more running airflow. Go into your base airflow table and add 10% across the board (multiply by 1.1). See if that helps.

joecar

ah, ok, thanks.

70caminoman

Oh **** I was multiplying the whole column by that number in the 800 and 1200 columns. I didn't know I should only be adjusting the cells that it hits at idle. Still getting used to reading the logs and adjusting the VE tables based on those cells. Makes sense when I read the stuff. Just never actually tuned before. It's a little daunting, makes me feel like I'm 15 again when I couldn't get a carburetor dialed in for the life of me.