SO I have the cut-out open. Because the O2 is not reading correctly, would this cause the car to run rich?

If so, any way I can have the cut-out open and not run rich? IS that where I would need a O2 sim? Which O2's should have the sim?

 

I am not entirely positive, but I think that O2 sims are for use with the rear O2 which only have to do with reading your emissions not correcting the mixture. You could O2 sim the front O2’s but that would basically make your engine run blind so I am pretty sure that’s a bad idea. As for correcting the problem I don’t know. That just my take on the subject
Good luck

 

Where is your cutout installed? Do you still have the factory Y pipe? If so, your cutout must be installed after the Y comes together, therefore after all 4 O2 sensors.

The rear O2s are only for reporting back to the PCM if the cats are doing their job. Basically, the PCM compares the front O2 reading to the rear O2 reading and determines the state of the cat. So no, you do not need any O2 sims because you've installed a cutout.

As for running rich, I don't think the cutout is causing that. Maybe the ported MAF could be causing it? Did you do any other exhaust modifications? Headers, offroad Y pipe, EGR mods, etc .... ?

Thomas.

 

The cut-out is below the passanger seat before the back tire. I have all stock exhasut and y-pipe.

I heard that if I had the cut-out open, the rear O2's would not read correctly.

Because I ported the MAF, what can I do to get it leaner? (In a couple of days, I am having the PCM tuned)

 

The rear O2 readings should not be effected by opening the cutout unless it was installed before, or very close to, the O2s themselves. Since you've installed it right before the rear axle, you should be fine.

I've read a lot about porting MAFs and the strange problems it can cause. I know there are a few professional tuners who won't even touch a car if the MAF has been ported.

Do you have access to a stock MAF, A friend whose you can borrow for testing maybe? If so, I'd try swapping in a stock MAF to see if it resolves it.

How did you determine it is running rich anyway?

Thomas.

 

A friend used his EFI to look at the car. The back bumper seems to have more black crap than usual.

Maybe some additive I can run through the system to clean it out?

 

To clean what out? If EFI Live is showing a rich condition, there is no additive that will help. A mixture problem can be caused by unmetered air entering the throttle body, or from an exhaust leak before the front O2 sensors, or from a sensor reporting invalid values due to malfunction (or porting in this case).

If the ported MAF isn't causing it, check for leaks in your air bellows and also in the exhaust manifolds (EGR, AIR, Manifold seals, etc ...)

Good luck,
Thomas.

 

Will do , thank you