First time tuning 94-95 $EE LT1. Does this sound right?

[ThatDude-98]

Theoretically, if I were to tune a '94-'95 LT1 ECM / PCM from start to finish, would this be the correct order and method(s) to do so?

Engine would be a: 1994-1995 350ci LT1 with stock bore and stroke. Stock injectors. Stock bottom end, roller lifters, OEM cylinder heads with oem valve size, full roller rocker arms (1.6 ratio), aftermarket valve springs, crane camshaft (.479 / .518 lift 272 / 286 duration, 112 Lobe Separation Angle), headers, OEM narrow band O2 sensor, dual straight pipes, etc.

Very first, make sure all ignition system components, fuel pump, fuel filter, sensors, etc are all in good condition and car is running as good as possible.

Next check for error / check engine codes, if there are any fix them.

Now get vehicle to idle (advance idle timing 2 to 5 degrees, increase idle speeds by 100 to 150 RPM, increase Idle Air Control deadband by 75-100 RPM.) Next go to switches and uncheck anything I deleted such as (EGR, VATS, etc, etc).

Now disable power enrichment & highway lean cruise mode. Then hook my ALDL cable to my OBD port, then ALDL to my laptop. Next open EEhack or TunerPro & then datalog using as many ranges of the accelerator as smoothly and steadily as possible (5% throttle, 10%, 15%, etc all the way up to wide open throttle.)

Drive home, click save datalog and stop logging, turn car off.

Upload datalog to Tunerpro (this is where I will add the actual changes to timing , fuel, etc, etc)

In another window, open EEhack to download and analyze the data captured on the datalog.

Now reference how much fuel the ECM / PCM asked be added or removed and add or remove the correct calculation yourself. The higher the number in the BLM table = the more fuel the ECM is commanding. A BLM > 128 = lean AFR, ECM adds fuel to compensate. BLM < 128 = rich AFR, ECM takes away fuel to compensate.

To fix your fuel tables Grab the cell you wish to change, as well as 3 immediate surrounding cells. Take your actual AFR / by your target, the answer gives you the percentage you need to change by. Multiply your BLM cell value by the % answer to make a change in the correct direction.

If your "answers" first digit is a zero you subtract fuel, if answers first digit is a one you add fuel by that percentage. Multiplying adds fuel, dividing removes fuel.

EX: AFR 10.3:1 & Target AFR: 13.2

1: 10.3 / 13.2 = .81
2: 81 out of 100
3: 100-81 = 19
4: the AFR needs a 19% change
5: take your current cell value X target percentage to get your target AFR.

OR option 2
Datalog with EEhack, open EEHack. Click analyze, run analysis.
1: Find in the cells where the EEhack analyzer tracked the BLM + or - %s
2: Now go back to TunerPro and correct those exact cells by the amounts provided by EEhack.

So now the vehicle idles and fueling is correct at all throttle ranges we correct timing.

1: Go to EEhack, click analyzer and click knock sensor
2:Areas in red are where the K.S pulled timing
3: Areas in green are where vibration, etc was picked up but timing was not decreased. Leave green areas alone.

Does this sound correct? Now I adjusted fuel as well as timing and should be good to go for all throttle and RPM ranges correct?

[steveo]

you might have a lot wrong depending on your setup.

do you have a wideband installed?

are you using a maf sensor?

[ThatDude-98]

I would tune using a MAP sensor and narrow band for the time being. I could switch between MAP and MAF if needed. Added a few edits since your reply. Good to hear from ya.

[WASyL]

For running MAP only use patch for accel enrichment or you will stuck with lean on acceleration. Also tuning cams with NB O2 is very hard due to cam overlap.

[steveo]

EX: AFR 10.3:1 & Target AFR: 13.2

1: 10.3 / 13.2 = .81
2: 81 out of 100
3: 100-81 = 19
4: the AFR needs a 19% change
5: take your current cell value X target percentage to get your target AFR.

OR option 2
Datalog with EEhack, open EEHack. Click analyze, run analysis.
1: Find in the cells where the EEhack analyzer tracked the BLM + or - %s
2: Now go back to TunerPro and correct those exact cells by the amounts provided by EEhack.

you won't have any idea what your AFR is without a wideband so you'll need to use option 2 here. as a new tuner you might want to consider just using a MAF, it's way easier, and the LT1 ecm is best designed for using a MAF for airflow. if you are using a MAF you leave your VE tables alone and tune the MAF table.

1: Go to EEhack, click analyzer and click knock sensor
2:Areas in red are where the K.S pulled timing
3: Areas in green are where vibration, etc was picked up but timing was not decreased. Leave green areas alone.

not sure where you heard that. green means you are not in power enrichment. red means you're in power enrichment. i would remove timing where there are clusters of knock events rather than just small events, but be aware that you can get false knock from engine noise, so if you remove a bunch of timing in an area and continue to get knock, it's probably not real knock.

Now disable power enrichment & highway lean cruise mode. Then hook my ALDL cable to my OBD port, then ALDL to my laptop. Next open EEhack or TunerPro & then datalog using as many ranges of the accelerator as smoothly and steadily as possible (5% throttle, 10%, 15%, etc all the way up to wide open throttle.)

first, the LT1 does not have highway lean cruise mode.

tuning your fuel by disabling power enrichment and using a narrowband o2 can be dangerous, as that extra fuel from power enrichment can prevent detonation under heavy load. your build is really mild, you might want to consider just using a MAF sensor and leaving high RPM fueling alone, the stock MAF calibration should be 'close enough' for you.

[Terminal_Crazy]

Don't make your changes the full amount of the trims. The trims do move around some affecting the averages and you'll overshoot, so make smaller adjustments.

HTH
Mitch

[ThatDude-98]

First things first, thanks all for the advice and input, I like how everyone is so willing to help others, it’s awesome- you don’t see that much any more I don’t care what the topic is. I’m not against a wideband, just trying to do keep this simple for starting out until I really get the hang of it. I also am not real familiar with how you hook up a wide band and all. I do know it’s used to read your AFR.

My info came from here at Gearhead, TGO & YT as well as a few other sites.

Thanks for correcting me when I make a mistake. Eventually I’d like to bore & stroke my engine..but that’s later.

So if I understand correctly, would this be how I tune MAF?: To tune MAF tables, open EEHACK, click data-log. Where it says MAF you’ll see a number or multiple numbers. Go back to your MAF table in TunerPro, find the MAF number(s) you located in EEHACK and grab it and 3 immediate surrounding cells. Change the values the same way you did MAP fueling. Remember if answers first digit is a zero you subtract. if answers first digit is a one you add.

Also leave PE on to prevent detonation. Also if I were to just tune idle, cruise and mid-ish range would I just leave timing columns 80-100 alone exactly where they are factory?

EDIT: doing maf research as we speak to see if I have it right. Again feel free to chime in with criticism

[LeMarky Dissod]

If I were to just tune idle, cruise and mid-ish range, would I just leave timing columns 80-100 alone exactly where they are factory?

After a drive that only includes idle, cruise, & 'mid-ish range' while EXcluding anything more fun, your logs will definitively answer this question for you. After such a drive, you should have a good idea of how to raise the WOT-PE thresholds so the borders of 'more fun' are better delineated, among several other things.