New to Tuning - Installed Stage 2 Cam - Won't hold idle after setting Base Idle RPM

[Metallurgist17]

Looking for advice and assistance getting my Gen 3 5.3L idling. Everything on the girl was left stock except upgrading the rockers, valve springs, and cam shaft.

Cam Shaft - BTR Stage 2 Truck Cam, 212/218
Roller Rockers -Harlan Sharp 1.7 Ratio

I increased the Base Idle RPM to 850 for now. Then adjusted the Idle Air Flow in gear and P/N up by 1.3%. I also increase the Idle spark Advance from 0-800 to 23. It doesn't start right away at cold but it does start but won't idle at my preset idle that I flashed (850). I even tried bumping the idle where I know it runs and still wants to drop down to low RPMs.

Once the engine warms up, it will run but still not idle. If I let the engine die, it won't fire back up. I reviewed my log file and the advance is jumping all over the place my STIT and LTIT seemed to making tons of correction. I feel like there is something else going on here causing the issue why it won't idle.

I attached my log file along with my tune that I flashed. I am open to any advice.

[horsepowerguru427]

Idle tuning is usually done after VE and/or MAF tuning. Read up on this, it should help more than me trying to explain it and its a basic HOW TO. I assume since youre using STIT and LTIT youre running a P01 since you never specified. Im at work and cant view the tune at the moment. The first link will give you the adjustment info you need for startup and what not. Also, post the rest of your cam specs. i believe its pretty much identical to mine sum-8719R1, if so, i can send you my tune file for reference when i get back home in the morning if it helps you.
https://forum.hptuners.com/showthrea...e-(w-pictures)
https://www.performancetrucks.net/fo...tricks-373848/

[Metallurgist17]

Man, I appreciate you helping out! I attached my cam card below, came through weird. Will wait to see what it looks like after I hit reply to Thread. I honestly said that wrong about the STIT and LTIT. Looking at my VCM scanner, its the short term and long term trim bank. I will take a look at the link you share and learn more off the VE and MAF.

BTR Stage 2 Cam Card.jpg

[Metallurgist17]

Also, please do share your tune file. Comparing what you have would help get me in the right direction.

[horsepowerguru427]

Also, please do share your tune file. Comparing what you have would help get me in the right direction.

About the only difference in our cams is the LSA, mine is 112+1, but my VE and MAF settings should be close enough for you to run. some things you wont want to change though. Ive also got a stall converter and some other mods, so dont just take all my settings. Mine idles fine @ 650 rpm when warm. Ill Post my tune file after i get home and a quick rundown of what you should change right off the bat...

[Metallurgist17]

The thread you shared in your first post is super helpful. I never even touched my VE or MAF during my initial flash. This is most likely my culprit to idle issues and not holding the idle/not starting after warmed up. Can't wait to see your tune with you comments. Did you run a 2200 stall?

[Metallurgist17]

About the only difference in our cams is the LSA, mine is 112+1, but my VE and MAF settings should be close enough for you to run. some things you wont want to change though. Ive also got a stall converter and some other mods, so dont just take all my settings. Mine idles fine @ 650 rpm when warm. Ill Post my tune file after i get home and a quick rundown of what you should change right off the bat...

I went ahead and adjusted my VE based on the feedback on the post you share. I backed off the VE table since my cam is not that big. I went ahead and multiplied 0.9 across the 400rpm, 0.95 across the 800, and smoothed the transition. I also adjusted the other parameters too. She stuttered to start so I bumped my idle advance up 1 more degree and she fired up. The rpm was tricky to idle on its own. Dropped down to 500 or so and acted like it wanted to die and then caught itself. After a about a couple of seconds wanting to die, the throttle finally took over and brought up to 900rpm. Felt good to see the truck idle on its own. Its odd to me that it took so long to hold that preset RPM. I had to shut the engine off and unfortunately, back to square one when it came to starting warmed up. It actually tries to start but doesn't catch. I'm thinking its an idle advance issue the way it cranks.

[tana99ss]

you have to have the right information in you log to know whats going on and too see where you need to make the adjustments, per your last log, looks like you stft and ltft are way off in closed loop. Meaning the maf table is not calibrated correctly. I see you made some adjustments to ve and some to BRAF but it was very minimal, i dont think youd notice too much of a difference.

when tuning idle these are some of the things i have on my logs


Engine RPM (SAE)
Vehicle Speed (SAE)
Throttle Position (SAE)

Intake Manifold Absolute Pressure (SAE)
Dynamic Airflow
Cylinder Airmass
Barometric Pressure
Mass Airflow Sensor
Mass Airflow

Engine Coolant Temp (SAE)
Intake Air Temp (SAE)

AEM - EQ Ratio ( only if you have a AEM wideband)
Equivalence Ratio Commanded

Trans Current Gear
Idle Desired RPM

Idle Air Control Position
Idle Air Control Desired Position

Idle Desired Airflow
Idle Startup Airflow
Idle Base Gear Airflow
Idle Base Sum Airflow
Idle Base PN Airflow
Idle Adapt (STIT)
LTIT Gear/ACoff
LTIT PN/ACoff

AC Pressure Sensor
AC Clutch Engaged

Timing Advance (SAE)
Idle Advance

Idle AC Airflow
Idle Cracker Airflow
Idle Follower Airflow

Short Term Fuel Trim Bank 1 (SAE)
Long Term Fuel Trim Bank 1 (SAE)
Short Term Fuel Trim Bank 2 (SAE)
Long Term Fuel Trim Bank 2 (SAE)
O2 Voltage B1S1
O2 Voltage B2S1

[Metallurgist17]

Ok, so I got the engine running again and noticed I have some DTC that I need to look at. Not setting of check engine light but could be yet another issue to my hard start. P0342 for my cam sensor that is pending. Going to look at my harness. I replaced the sensor sice I was there but I install the old one back in. Mor to follow.

[horsepowerguru427]

Sorry for the late response, i figured instead of just posting my tune and letting you try and figure it out id make some changes to yours. i did add in my VE and MAF tables and few other things so it should run. I also disabled LTFT and CL, i do my tuning in OL with STFT, except WOT and PE which require a wideband. I also disabled the MAF and set OL EQ to 1.0 after about 80 degrees, disabled DFCO and COT so there arent any fueling changes being made that you dont have control of. I removed most of your torque management settings so itll run better and probly spin the tires now lol. If it fires up and runs then let it warm up a couple of minutes and go get a good log, like 15-20 min of all types of driving, highway, in town, mid throttle, light throttle, off the line, acceleration while already going, ETC. Just dont get into PE or WOT! which i changed those settings so as long as you dont go past about 80% throttle you should be ok, and it really shouldnt come on even then. then apply that data to the VE table, make sure your lables on you histogram are the same as the lables in your VE table though. After applying the data to the VE DO NOT smooth the whole table. go through and interpolate any cells you did not get data for that are in between other cells of your data (see screenshot I used as an example) Be sure when using interpolate feature that the first and last cells you select are YOUR data, not something that was already there. Do these interpolations one at a time and not in big lumps and if there are any big transitions from one area to another then smooth that small area. Then go get more data and do this process a few times until your STFT is reading only about 1-2% error. Once youre happy with the VE then re enable MAF so it doesnt use VE and tune the MAF the same way. when that is done, then set dynamic air, MAF fail hertz, LTFT CL, PE, WOT, DFCO, and COT (IF YOU STILL HAVE CATS ONLY) back to factory and see how it runs. After all that is tuned then you can accurately tune the idle settings if you need to, however i alter a few of those as well, hopefully it fires right up and runs like a top. Let me know how it turns out, im off work til thursday night so ill be on here quite a bit if you need help.

P.S. do not forget to clear fuel trims in the special features of the scanner on the right side of the fuel tab, not the LTFT reset, before you log any data. if you do not then you will not get accurate data.

[Metallurgist17]

Sorry for the late response, i figured instead of just posting my tune and letting you try and figure it out id make some changes to yours. i did add in my VE and MAF tables and few other things so it should run. I also disabled LTFT and CL, i do my tuning in OL with STFT, except WOT and PE which require a wideband. I also disabled the MAF and set OL EQ to 1.0 after about 80 degrees, disabled DFCO and COT so there arent any fueling changes being made that you dont have control of. I removed most of your torque management settings so itll run better and probly spin the tires now lol. If it fires up and runs then let it warm up a couple of minutes and go get a good log, like 15-20 min of all types of driving, highway, in town, mid throttle, light throttle, off the line, acceleration while already going, ETC. Just dont get into PE or WOT! which i changed those settings so as long as you dont go past about 80% throttle you should be ok, and it really shouldnt come on even then. then apply that data to the VE table, make sure your lables on you histogram are the same as the lables in your VE table though. After applying the data to the VE DO NOT smooth the whole table. go through and interpolate any cells you did not get data for that are in between other cells of your data (see screenshot I used as an example) Be sure when using interpolate feature that the first and last cells you select are YOUR data, not something that was already there. Do these interpolations one at a time and not in big lumps and if there are any big transitions from one area to another then smooth that small area. Then go get more data and do this process a few times until your STFT is reading only about 1-2% error. Once youre happy with the VE then re enable MAF so it doesnt use VE and tune the MAF the same way. when that is done, then set dynamic air, MAF fail hertz, LTFT CL, PE, WOT, DFCO, and COT (IF YOU STILL HAVE CATS ONLY) back to factory and see how it runs. After all that is tuned then you can accurately tune the idle settings if you need to, however i alter a few of those as well, hopefully it fires right up and runs like a top. Let me know how it turns out, im off work til thursday night so ill be on here quite a bit if you need help.

P.S. do not forget to clear fuel trims in the special features of the scanner on the right side of the fuel tab, not the LTFT reset, before you log any data. if you do not then you will not get accurate data.

tana99ss started to help me out yesterday looking at my tune as well. I did load your tune up and definitely was responsive on that tune but smelled super rich and never fired up. I think I have an issue with the cam sensor because it is acting like its not timed write. Loaded my original tune that it fired on and just cranks over with firing. I have no codes present.

[Metallurgist17]

Need to do some work. Unplugged the battery for an hour, plugged back in, fired right up. Dont know why but it decided to throw codes. P0342, P0343, and and a mass air flow (this was one is understandable). I replaced the cam sensor with an aftermarket so off with the intake to put the old one back in. It worked before, so why not. Will check my wiring while Im back there. Hard start when the sensor is acting up.

[Metallurgist17]

Update: ripped my intake off and installed my original cam sensor. I then checked the electrical circuit between my sensor and pcm, which was ok. Put it all together, reset codes, and it started right up. Let the engine warm up, shut off, started right up with a little foot action. Here I thought installing a new sensor would be proactive, caused myself way more pain then it should have. If only that sensor gave me a decent code instead of leaving me puzzled. Now off to the races with the tuning.