how does a tune work without a wideband?
Pro
Joined: Feb 2003
Posts: 745
Likes: 136
From: Detroit MI
In short, he doesn't.
In closed loop, where the target AFR is close to stoich, the narrowband sensors will attempt to correcy, but never really get any closer than +/- 3% error. ( A good wideband is <0.5% error) Under power enrichment or cat protection where the target AFR is richer the narrowbands are COMPLETELY USELESS and potentially misleading. Anyone tuning by narrowband voltage at WOT is asking for broken parts. Period.
In closed loop, where the target AFR is close to stoich, the narrowband sensors will attempt to correcy, but never really get any closer than +/- 3% error. ( A good wideband is <0.5% error) Under power enrichment or cat protection where the target AFR is richer the narrowbands are COMPLETELY USELESS and potentially misleading. Anyone tuning by narrowband voltage at WOT is asking for broken parts. Period.
Advanced
Joined: Oct 2008
Posts: 76
Likes: 0
When i had my car tuned by someone using EFILive he was getting readings from some sensors like knock ping retard something like that. I'm not sure how it works exactly but he was systematicly ajusting AFR at different RMPs and throttle position till all the little graph boxes turned from red and orange to green lol
Pro
Joined: May 2000
Posts: 610
Likes: 1
From: Midland Texas
St. Jude Donor '09-'11
If you are talking about wide open throttle tuning, the tuner temporarily installs a wide band sensor and then datalogs the wide band output with the engine data at wide open throttle. I use an AFM-1000 in a bung ahead of the cats. If the car doesn't have a bung, I have the owner add one before tuning the car. If the car has an off road pipe I use the rear O2 sensor bung for the wide band. Once tuned, when the car is run at wide open throttle, the engine should hit the same air fuel ratio as it did when the wide band was installed, until something else is changed on the car like the air meter or the injectors.
For cruise tuning at light loads, the tuner datalogs the fuel trims which are a result of the signals from the car's front sensors at stoichiometric air fuel ratio. The result can be checked with a wide band, but that isn't always done.
Joe
For cruise tuning at light loads, the tuner datalogs the fuel trims which are a result of the signals from the car's front sensors at stoichiometric air fuel ratio. The result can be checked with a wide band, but that isn't always done.
Joe
Former Vendor
Joined: Feb 2007
Posts: 2,572
Likes: 1
From: Austin Texas
Tuning with a good wideband make tuning much easier and they are a must have for WOT tuning. The stock narrowbands will work for part throttle tuning and will give readings for the short term and long term fuel corrections. Then, you apply the corrections for the VE table and/or MAF table. If you use a WB for part throttle, you log the commanded AFR along with the WB AFR. Then, apply the percentage difference between the two to the VE/MAF tables. For WOT, the PE table is set to the commanded AFR (by rpm) and adjust the MAF Table to achieve the desired AFR. For speed density, the VE table is adjusted.
