how does an Etune work?

 

On another note had some issues yesterday night on the drive home after getting new rear tires. When I was about to get on the freeway I notice my afr gauge went offline. While on the throttle the car kept hesitating and wouldn' boost past 5psi. It would just bounce between 4 PSI and 5psi no matter the throttle. Under 5 PSI the car drove fine.
1. Clutch slipping?
2. Belt slipping?
3. New tires not gripping?
4. Af gauge offline cause ems to go into limp mode?

 

Sounds likely a no on 1, 3 and 4 based on what your explanation on the cars behavior was. Not to beat you up, but if you cant tell the difference between a clutch slipping vs tires vs sc belt, this one might be extra challenging to try and figure out for you behind the computer lol. It either a spark or fuel issue in some manner. Possibly its the belt slipping prompting the issue, which could be the tuner not accounting for this in his tune, with providing enough or way too much fuel in the cell surrounding the normal boost/fuel plot. if the gauge reads --- that means lean off the charts if the gauge still reads properly. If the belt slips, it falls out of the normal trajectory of the fuel/boost tables and depending on where those cells are surrounding, could make the engine run like shit, especially if it goes super lean or super rich, sound like maybe super lean based on gauge which is bad news on your motor. Since you said you weren't making more then 4-5psi, id start at checking the belt tension, give it a re snug and see what happens.

 

Thanks for the input. I'm just throwing a bunch of possibilities out there. I think it is most likely the belt slipping. I know for the clutch is its slipping my rpm would be going crazy. As far as tires go i had a new set once and didn't completely burn coating off yet and the psi were set at 32/40 from the shop so it gave me traction issues on the freeway. And as for the limp mode my BMW does it whenever it detects a boost leak or misfire it'll throw the car into limp mode until the next start up. I tighten down the belt some more and took it out for a drive. Seems to be doing better. It'll stutter at 6psi for a split second and then pick up. I ordered a new belt and will swap it out asap. Thanks again!

 

Sounds like a tuning issue, but the belt may very well be loose as well. Pay attention to your afr. Should be between 11-13afr at WOT, 11 being on the heavy/rich side and 13 being lean. You go too far south or north of that afr and you will start to run shitty, either bogging out/blowing smoke or engine cutting out. Rich and bogging in the short term wont blow motors, but lean will. Pay attention.

 

 

I messaged you