Does it run lean?

[SVTerror]

Not sure where this question exactly goes. Does going from a stock mid-pipe to...lets say Mac Prochamber mid pipe (without cats) with mil eliminators (no tune) cause the A/F to go lean on the stock tune? I tried searching and I couldn't find anything concrete.

 

[TBCobra]

If you still have the front 02 sensors I don't think it would make a difference.

 

[gmtech]

Just adding a midpipe will not cause the car to run lean. The rear oxygen sensors only monitor the converter, they have no say in A/F Ratio.

 

[SVTORANGE]

It will go into limp mode till you get car tuned!

 

[SVTerror]

Ok, thanks guys, that makes sense. And LOL about the limp mode.

 

[aarons04cobra]

Ok, thanks guys, that makes sense. And LOL about the limp mode.

Limp mode! LOL

 

[SVTORANGE]

Limp mode! LOL

LMFAO - Yes sir sounds better than RETARD mode don't want to offend anyone so LIMP mode it is

 

[Mach828]

I'd say you need to get it tuned. Put a catback on mine, vehicle went to retard mode on the first pull. Had to get it towed home.

 

[Rich'sTRsvt]

With just a catback? that is weird. With MIL eliminators it should be all right.

 

[mhinchley]

Did you go catless when you added the cat back?

When removing the cats with a catless midpipe. The problem is the rear sensors will think something is wrong with the cats. The MIL elims would cure this as would turning them off with a tune. Fuel adjustments are made by front sensors. Monitoring the cats is the job of the rears.

The front sensors should adjust the fuel from going lean under normal throttle. WOT is where there would be a chance at going slightly lean, but I just installed headers, and my wot afr stayed exactly the same. Have an afr gage? Easy to tell. If you don't, now is a good reason to get one. A must on a boosted car.