Not Programming

[DE07GT]

Also, the reason rear O2s sensors are disabled in just about every custom tune is due to the fact that the catalytic converters are removed. The rear O2 sensors have NO control over your fueling.

The changes in a closed loop fuel system is partly based on feedback from the O2 sensors. Varying voltage readings from the O2s tell the computer whether or not the exhaust is rich or lean. There would be no point in having the rear O2 sensors if they're just meaningless sensors.

After checking some diagnostics while idling, you can clearly see the short term fuel trims adjust rich/lean back and forth with readings ranging from only -2 to +5. This means that the car is running more rich than it is lean.
I have yet to have a good clear day outside where I can log the diagnostics under different loads. As long as the rear O2s are enabled, they will affect feedback whether I clear the codes or not, so that is why my rear O2s will be disabled once I load my custom tune.

Also, you mention something being wrong with your Predator...that is so not the case.

If that is not the case, then why would the Diablosport support line tell me to send my Predator back to them so they can "fix it"? A tuner not reading the ignition in the key sequence when installing a tune means there is something wrong. My guess is some stupid software problem considering you have to have the ignition on to do diagnostics. It will recognize it then, but it won't any other time.

Get the car to a good quality Mustang shop and see what they have to say.

I would, but I do not have the time or the money considering I'd have to drive at least 70 miles to the closest one. It's bad enough I have to pay for shipping for a product under warranty and then pay up to $100 to get the computer flashed back to the factory tune before I could use the Predator once I got it back.

[Vas@Diablosport]

The changes in a closed loop fuel system is partly based on feedback from the O2 sensors. Varying voltage readings from the O2s tell the computer whether or not the exhaust is rich or lean. There would be no point in having the rear O2 sensors if they're just meaningless sensors

You are correct... if you are speaking of the front o2 sensors, the rears simply tell the vehicles computer if the catalytic converters are working as designed. The reason why they are turned off in most tunes is because most mustang owners install catless x-pipes and if the rear o2s weren't tuned off in their tune, the CEL would be on to tell them that the cats are not functioning properly.

After checking some diagnostics while idling, you can clearly see the short term fuel trims adjust rich/lean back and forth with readings ranging from only -2 to +5. This means that the car is running more rich than it is lean.

Your STFTs at idle ARE going to vary crazily at idle. You will need to monitor your LTFTs while actually cruising down the road to get a proper reading.

As long as the rear O2s are enabled, they will affect feedback whether I clear the codes or not, so that is why my rear O2s will be disabled once I load my custom tune.

Again, your rear o2 sensors do not play a role in how your vehicle runs.

... and up to $100 to get the computer flashed back to the factory tune before I could use the Predator once I got it back.

Again, you should not have to get the vehicle flashed back to stock, if you have a CAI on the vehicle, take it off in the meantime.

[mikel]

Again, sir, please go back to the drawing board and research how these systems work, rather than trying to argue with us about it.

The rear O2 sensors are useless for anything except to know if your cats are functioning, period.

[DE07GT]

I datalogged after clearing the codes and without clearing the codes and there is an obvious difference between the two. The test runs consisted of light to mid to heavy throttle. The engine was warmed up in both tests and conducted in 70 degree clear weather.
When I cleared the codes after startup, the fuel trims adjusted back and forth between -1 and +1 under all loads, keeping the AFR about constant. When the codes were not cleared on startup, the fuel trims were always positive, going from +3 all the way up to +10. In this case, fuel trims are never negative and increase to pig rich under load.
Running this rich while getting my predator fixed could result in my front O2 sensors failing if the repair takes too long. Granted, it is better for it to be running rich than lean, running this rich is not good for the motor.

I do not have a CAI. The only change is an X-pipe with high flow cats. I am currently running the 93 Performance tune, but the Predator won't work when it comes back if there is already a tune on the car.

[mikel]

....again, you are not getting it sir.

The fuel trims are constantly adjusting to keep your A/F ratio stoich, or 14.7:1. Positive fuel trims by NO means mean you are running rich, in fact, they are telling you that the PCM is adding that % of fuel to keep you at 14.7:1, so in essence, the PCM is adding fuel to correct for a lean situation, but the A/F will never change from 14.7:1 under cruise/part throttle since the trims will always adjust to keep it there.

[DE07GT]

Do you own a Mustang or drag race one on a consistent basis like many people I know? The computer's adjustments aren't always correct as you seem to think they are. That's why just about every single thing you add on an 05+ Mustang requires tuning. The computer will either under- or over-adjust to added airflow.
Even if I'm wrong, you can't argue with the fact that it is adding way too much fuel. Fuel trims should never be going as high as 10 when the engine IS NOT running lean. A stock engine with just an X-Pipe will not run so lean that it needs to add that much fuel.
You must not have actually read through my entire post considering these tests were conducted with the same exact conditions and the only variable being the clearing of the pending code. The whole point of this is that the computer THINKS the engine is running lean when it actually isn't, so what it does is add fuel when it actually shouldn't be. After doing even more research on this, someone had the same exact problem on an S197 Mustang and asked about it in a Mustang magazine. The answer was that he needed a custom tune to turn off the rear O2 sensors, and the car would stop running so rich. They've only worked on hundreds of Mustangs, but I guess they have no experience at all when it comes to this according to you.

[mikel]

Not sure what to do or say sir...maybe you should contact one of the custom tune dealers on this site that can assist you with a better explaination than I can.

[DE07GT]

It seems like you know a lot about computers, but not that much about engines. A P0421 or P0431 code will make the computer think that the catalytic converters aren't warming up like they should be, so the computer adds fuel to try and get the cats up to operating temperature. When the non-stock cats are in place of the stock ones, they will never reach the point where the computer thinks they should be because the exhaust flowing through them will have a different percentage of oxygen than the stock cats. This keeps the computer in constant rich adjustment for what it thinks is a lean condition, when it actually isn't. I've talked to a tuner, but can't use a new tune until my Predator is fixed.

[DE07GT]

I cannot afford to send my Predator back in since I get approximately 6 mpg worse without clearing the codes.
And this topic should not be considered Answered, because I have yet to hear ONE explanation why a predator wouldn't recognize the key sequence. The only thing you ever hear is the generic answer from Diablosport. "Do you have any aftermarket electronics installed on your vehicle." Then when you tell them you don't, they have absolutely no idea what's wrong.

[DE07GT]

So when I ask a genuine question, all I hear is crickets? Plenty of people complain about the key cycle issue and you have absolutely no idea why.
And as far as my car running rich, my exhaust tips have turned black in the 2 weeks since I sent my Predator in. I've cleaned them once since then, but they are black already. When the codes were cleared at all times, my exhaust tips NEVER turned black. My fuel mileage has gone done 2-4 mpg when I was actually trying to get good mileage compared to before.

[DE07GT]

Thank you Diablosport. You are such a big help. After you guys "worked" on my Predator for 2 weeks I now have a worthless car. The Predator was not reset like it was supposed to be, so it told me it needed to restore the original tune. Once I restored it to the car, my car will not start and the Predator will not read the car. Now I have to take the computer out of my car, somehow find a way to get to the dealership without my daily driver, and then pay either $100 to get my car flashed back to stock or even higher for a new computer. I'm not paying to get my car towed just because something is wrong with your software...I am not made of money. After this, I will most likely be locked out of the Predator and have to jump through hoops to get everything back to normal...and that's if I'm lucky. Knowing my luck, your customer support will tell me to pay more money to send the Predator back in again after I just got it back. Who knew it could cost upwards of $500 to install a working tune on a car?