Just like the title says, Im having ptb(part throttle boost) and its leaning out really bad b/c Im still in closed loop. Wondering if any of you guys have had any of this, and what you did to fix this?

I had a t3/t04e, now I have a t3 super? 60 and getting bad ptb. Its only when accelerating like in second and third gear around 3200k and up on part throttle. It gets real lean when it hits ptb, boost is from 1-5 psi thats the max it'll boost cause the engine is starving for fuel.Its starts leaning out as soon as it goes from vacuum to boost, I either have to wot or let off the throttle when this happens.



Its external wastegated(38mm tial)8-9 psi, 440cc greentops,255 walbro,fpr at 44psi,aem f/ic for tuning,aem wide band,greddy bov, and never had an issue with my bigger turbo which I might end up getting a another bigger turbo if I cant solve this haha. Hope you turbo gurus can help me out a little on what you guys did. Thanks

 

There's no part throttle tuning with the aem fic?

 

Did you retune after the turbo change? Are you using the on board MAP in your fuel and O2 maps?

 

Try unplugging the 02 sensor and running in open loop all the time, I have a bad lean spot when I have to plug it in for the smog test.

 

I second that. Leaving both factory o2's unplugged will keep it open loop mode which if you see the lean spot go away you know the factory ecu is causing your issue. I use to have to do this all the time when I had my SAFCII for fuel tuning. If all else fails you can always join the darkside " MegaSquirt" like I did. lol. Try unplugging those o2s it will work.

 

Bmxer I have it set up just like radu has his for.Then adjusted some fuel on idle. So yes to your questions, Im using the on board map..



Tanc I do not think it has part throttle tunning with the fic. I tried to adjust the fuel tables in the area of ptb but no change, then I realized its still in closed loop..



Im goin to unplug both the o2's and see if any change...I'll let you guys know if any improvement. I know there has to be another way, hate seeing that cel all the time.. thanks for the input

 

The FIC HAS partial throttle tuning. You need to change you tune for your turbo. If you open up your Tune, you can see where it is set for Maf Clamp, and then you can see what percentage your injectors are at and at what percent of load.

 

Yeah you can easily part throttle tune with the fic..



Wouldn't do the unplugging o2 sensor deal though since its not a stock ecu issue..

 

I have an 05 Beta II Tib with a supercharger setup on it, 12lbs. of boost. I had the same problem with my setup. I use an FIC for fuel tuning.



I ended up running both O2 sensor signals through the FIC and reducing the O2 signal voltage a little before boost starts, pretty much cured the lean, low boost issue.



I have the O2 modifies setup as MAP load and offset mode.



I use a value of -.402 in the whole table starting at 13.5lbs absolute pressure.

 

Yeah I was thinking of something else on the part throttle tune.lol, I have added fuel where it was leaning out on the fuel table, maybe just not enough, I have my o2 set up with percent mode, starts at -10.2 at 12.5 psia then at 15 psia -20.7 rest of the map. I might mess with this a little. I guess ima go out and test drive it again with my laptop to see where the load and percentage of the injectors are at the ptb area and add more fuel.maybe lower my signals for my o2 sensors.