Avery Marchbank

I just completed my 2002 c5 corvette base build, did hand ported 241 heads, tsp ms3 cam, and hand ported throttle body. Plugged everything up and got to tuning. Turns out the previous owner got the pcm tunned and it was locked, so I swapped in a new pcm and flashed on the base tune. After a few hours of tuning I can’t seem to figure out why it’s still 20%+ lean at idle on both banks and getting code P0106. Lean condition goes away driving normal and at WOT, but will sometimes go to about 5%.i have No exhaust leaks, and have plugged off every vacuum valve on the intake and still lean. Even tried spraying brake cleaner around the throttle body and intake to see if it revved and it didn’t. Replaced map sensor and still getting code. I’m lost. Has Anyone had a similar problem or have any suggestions?

dw456post

You probably need to add more fuel with the maf and ve table. Got a tune and scan that you can post?

G Atsma

O2 sensors check out OK?

Avery Marchbank

O2 sensors are brand new. And We’ve added 20% fuel at idle and still 20% lean. Not sure how to post a scan on here. Just made the account

ddnspider

iTrader: (26)

Why are the O2 sensors on if you're tuning it? You need to adjust the VE and MAF tables in open loop with no O2 additions. Besides, assuming you have longtube headers, they are notorious for giving a false lean at idle, especially with a cam.

Avery Marchbank

we have the maf off to tune the VE table. Are the O2s supposed to be off too? My understanding speed density reads from map and o2s. Also how do I fix that issue?

ddnspider

iTrader: (26)

Do you have any tuning experience? You really should read some of the sticky's and check out HPT or EFI Live tutorials. You should be using a wideband O2 sensor to tune given your mods. Narrowband factory O2's should be turned off along with all trims. Do as you said and kill the MAF, tune the VE table, then do the opposite.

Avery Marchbank

I have only made very minor changes to the tune. A friend of mine has been doing the main tuning for me for a couple of days. But we’ve been stuck on this. And we are just doing a basic street tune right now so I can take it to the dyno and get a good tune on it. And I will definitely check out some of the sticky’s!

Cooper Smith

Wouldn't you reset LTFT (I know it's redundant, but it would make sure your data isn't skewed) and turn them off by raising the Min ECT to 284 so they never turn on. Engine>Fuel>Oxygen Sensors

Also turn off your DFCO when doing your VE and MAF.

ddnspider

iTrader: (26)

Until you learn more and get the proper setup, I would not let your friend make a bunch of changes. What software are you using?

dw456post

To turn off the maf, you need to 0 the maf plus in dtc's, P0101,102,102 need to be MIL on first error. You can leave the boxes checked if you don't mind the light. Dynamic air High disable to 8000. If you are using a wideband, you don't need the trims (O2's)on. If you don't have a wideband, you can tune the lower rpm's up to 4000 with NO WOT with STFT's pretty close. Make an afr error chart so you can modify the ve table with it. Like said above, turn off LTFT's and DFCO and COT.

ddnspider

iTrader: (26)

You're not going to dial in idle AFR with narrowband O2 with longtubes and an MS3 cam.

Avery Marchbank

hptuners

ddnspider

iTrader: (26)

https://forum.hptuners.com/showthrea...o-and-how-to-s

fst100

iTrader: (5)

honestly, i second a wideband.

dw456post

He said he wants to get it driveable so he can take it to a good tuner. He can get it close as long as he doesn't have open headers.

ddnspider

iTrader: (26)

Sure, I guess I just think if he gets a wideband and some reading, he can finish tuning it himself. He's already paid for credits on his HPT.

ChopperDoc

This should help... Full VE tuning guide, including how to set up the scanner and everything. Got tired of typing out the steps every time this came up lol.

dw456post

Yep, you are correct

Avery Marchbank

Just threw in a wideband and it’s hovering right around 14.7 so it’s not lean. Still a little weird because it doesn’t want to start up and idle without me giving it some throttle for a minute. And sometimes it’s wants to die at a red light.