FWIW - I drove my car at 1/8 tank of gas at the drag strip and on the street and never once saw lean conditions even under WoT. My car was rarely over 1/3 of a tank the entire time I had it in case I ever felt like going fast. Same reason I never take a spare with me or road gear.

I don't think this is as big of an issue as people made it out to be.

 

Well the tank is full and its still flatlining and staying flatlined lean when im on engine decel.

 

You do realize that if your driving with say 20% constant throttle holding near 14.7 then let off your A/F will go off the charts "lean", that is normal.

 

Yeah, I actually went back and read what all he was describing and it doesn't sound abnormal to me.

 

When you say this do you mean permanently lean till i apply throttle again?

Again, when it does this it feels and sound rough, I can feel the roughness in the pedals etc.

When I had the vortech and i did this it would also flatline lean... temporarily, then after a second or two fluctuate with the engine load while slowing down.

Is there a difference between sc and turbo that does this?

Thanks.

 

not the FI per say, but the EMS or reflash

 

Well mine was never really rough.

You should check for exhaust leaks. Mine was dipping lean at idle and sometimes when I let off when I had a bad exhaust leak on the wastegate piping.

 

It is in the Ecu strategy for it to shut off the injectors completely on decel(fuel economy ,emissions) .100 % normal .

Sam

GT Motorsports

 

So using a utec or vpro would not change any of this then?

 

When lifting the throttle during engine braking, the ECU does not provide any fuel as Sam stated regardless of ECU. You do not need to try to add fuel to correct this.

The engine is effectively an air pump and the AFR will be 'off the scale' lean. The condition is not present when you put it in neutral or push the clutch in because you have removed the load and it is, in effect, idling.

 

No this is the way it is suppose to work, there is no need to change it. Even though with the VPro I am able to change it if I wanted to, but again it is normal.

sam

GT Motorsports

 

Got it, thanks.

I have to figure out why its rough on decel then if its not the ecu.

Again I appreciate all the input from everyone.

Freeze.

 

Are you sure you just aren't hearing "popping" in the exhaust when you decel? If so, that's normal.

 

No, its def a vibration. I dont even hear the exhaust on this car anymore, LOL, its like driving an electric car with a bov.

Something that came to me tonight that I didnt even think might be the issue with the decel vibration.

When the kit was getting installed, the tech had clearance issues with the intake touching the side of the rad. When i picked up the car he said he got lots of clearance by adjusting the motor mounts.

Thinking about the engine torquing over under load one way and shifting back the other way under decel, I could be on to something.

 

Whooooaaa... adjusting motor mounts? It's a tight fit but I've never heard of someone going that far to get it to work. hmm

 

You sure some piping isnt rubbing under the car and you feel a vibration as rpm's drop??

 

Not sure about the pipes underneath. Im gonna take the car back and have them readjust the motor mounts back to stock, im sure it will just fall back into the original spot.