SCT Tune - KRC Performance

[SlvrSnake]

I just had a new trans put in the truck so I am taking it easy for awhile. I have been using the stock tune and today decided to re-flash the computer after putting about 230 miles on the new trans. I used the 93 Octane from Marty to basically keep the engine running cooler. Keep in mind not beating on the truck here, just driving her normal.

Anyway, here is my question. I noticed when cruising around 65 + and letting of the gas to let the truck coast (like you would when rolling up to red light in the distance) I could feel the truck start to slow down more than normal. I did not notice this before putting the performance tune in. I did this repeatedly to see if it was my imagination. Nope not imagining things, the truck kept doing it. It was not a down shift, my best guess is the lock up torque converter was disengaging when coasting. If I let off say around 80 it would take about 2 seconds and then you could feel it really start to slow down, slight increase in RPM when this occurred, that is why I am guessing torque converter. It definitely did not down shift, stayed in 4th.

I flashed it back to stock and its back to normal, not doing what I described above.

Anybody got any ideas on this one, or has anyone noticed this problem with their tune.

 

[supercar1of1]

I just had a new trans put in the truck so I am taking it easy for awhile. I have been using the stock tune and today decided to re-flash the computer after putting about 230 miles on the new trans. I used the 93 Octane from Marty to basically keep the engine running cooler. Keep in mind not beating on the truck here, just driving her normal.

Anyway, here is my question. I noticed when cruising around 65 + and letting of the gas to let the truck coast (like you would when rolling up to red light in the distance) I could feel the truck start to slow down more than normal. I did not notice this before putting the performance tune in. I did this repeatedly to see if it was my imagination. Nope not imagining things, the truck kept doing it. It was not a down shift, my best guess is the lock up torque converter was disengaging when coasting. If I let off say around 80 it would take about 2 seconds and then you could feel it really start to slow down, slight increase in RPM when this occurred, that is why I am guessing torque converter. It definitely did not down shift, stayed in 4th.

I flashed it back to stock and its back to normal, not doing what I described above.

Anybody got any ideas on this one, or has anyone noticed this problem with their tune.

The convertor clutch is staying locked up longer on purpose.

My tuner here at M.V. programmed my Town Car the same way.

He explained why they do this on a performance tune, I just can't

remember right now why, other than it is OK.

 

[rottenronnie]

I just had a new trans put in the truck so I am taking it easy for awhile. I have been using the stock tune and today decided to re-flash the computer after putting about 230 miles on the new trans. I used the 93 Octane from Marty to basically keep the engine running cooler. Keep in mind not beating on the truck here, just driving her normal.

Anyway, here is my question. I noticed when cruising around 65 + and letting of the gas to let the truck coast (like you would when rolling up to red light in the distance) I could feel the truck start to slow down more than normal. I did not notice this before putting the performance tune in. I did this repeatedly to see if it was my imagination. Nope not imagining things, the truck kept doing it. It was not a down shift, my best guess is the lock up torque converter was disengaging when coasting. If I let off say around 80 it would take about 2 seconds and then you could feel it really start to slow down, slight increase in RPM when this occurred, that is why I am guessing torque converter. It definitely did not down shift, stayed in 4th.

I flashed it back to stock and its back to normal, not doing what I described above.

Anybody got any ideas on this one, or has anyone noticed this problem with their tune.

Sounds like the tune shuts the injectors off earlier than it used to, that's all. You can have it changed to delay the injector shut down if you prefer.

 

[SlvrSnake]

The tune shuts the injectors off earlier than it used to, that's all. You can have it changed to delay the injector shut down if you prefer.

So I am feeling, I guess engine braking from the injectors shutting down? Everything was fine except I noticed this today. Did not remember it doing it before (with the tune and old trans) but then again maybe I just never noticed.

If that is normal, no big deal. Just seemed a little odd. I can always ask Marty about it. Was going for the quick fix from the forum.

 

[1qksrt]

If there is any questions or doubt,By all means call Marty!
He is a standup Guy and will help out with any questions you mightv have with your tune!!!!!:rock:

 

[amtrucker22]

My tune from Marty did that too.

 

[Yellow venom]

My KRC tune does the same,I like it better,don't have to use the brakes as much.

 

[rottenronnie]

So I am feeling, I guess engine braking from the injectors shutting down?

Yup, and you will probably hear a change in exhaust pitch when it does it.
They do it to gain a little mileage; no point in firing injectors if you are decelerating.

 

[SlvrSnake]

My tune from Marty did that too.

I guess the post right above answers the question below. Injectors shutting down to save mileage. Right?

Did that or does that? Did you have Marty correct it or does it still do it?

I see others have noticed it too, so I am not worried about it. I am just curious here. Anyone know the reason for it with the tune? I.e. Is there some type of benefit?

 

[rottenronnie]

I guess the post right above answers the question below. Injectors shutting down to save mileage. Right?

Did that or does that? Did you have Marty correct it or does it still do it?

I see others have noticed it too, so I am not worried about it. I am just curious here. Anyone know the reason for it with the tune? I.e. Is there some type of benefit?

The factory does this to save mileage and lower emissions (to near zero), yes. It is programmable in the e.c.u..
You can have it changed (when the injectors shut down), as per personal preference.