Closed loop

[ExSRT8Guy]

Did a search; no luck.

At what temp does closed loop kick in?

 

[BruceH]

It's time based but the amount of time depends on the startup temp. Anything over 35 degrees stays in open loop for 15 seconds in the stock tune.

 

[ExSRT8Guy]

I'm guessing that's after it's already warmed up? When it's (the engine's) cold, doesn't it stay in open loop until coolant is up to a specific temp? Mopars and GMs I've owned operate this way.

 

[Swarzkopf]

No, like Bruce said it's time and coolant temperature based. It doesn't just switch at a certain temp.

Right from my stock file:

At -20 degrees coolant temp, closed loops engages 120 seconds after startup.
At 0 coolant temp, it takes 80 seconds
At 20 coolant temp, it takes 45 seconds.
At 60 degrees and higher, closed loop engages after 15 seconds.

Hope this helps.

 

[ExSRT8Guy]

No, like Bruce said it's time and coolant temperature based. It doesn't just switch at a certain temp.

Right from my stock file:

At -20 degrees coolant temp, closed loops engages 120 seconds after startup.
At 0 coolant temp, it takes 80 seconds
At 20 coolant temp, it takes 45 seconds.
At 60 degrees and higher, closed loop engages after 15 seconds.

Hope this helps.

Yeah, big time! This is different than what I'm used to. My last rig - Magnum SRT8, which I bought new and had for 7 years - didn't go into closed loop until coolant temp hit 165, or thereabouts. Thanks, Guys!

 

[Swarzkopf]

No problem man. Always loved those Magnums, too.

 

[ExSRT8Guy]

No problem man. Always loved those Magnums, too.

The Magnum was badass, and surprised a lot of guys. If it had a stick, I might even still be driving it, but that Mercedes 5-speed A/T leaves a lot to be desired.

I've had bunches of Mustangs over the past 30+ years - every generation except Mustang II - and the S197's the best by far. It's great to be back!

 

[BruceH]

I'm guessing that's after it's already warmed up? When it's (the engine's) cold, doesn't it stay in open loop until coolant is up to a specific temp? Mopars and GMs I've owned operate this way.

I'm thinking that there are other values used for the transition to closed loop but I couldn't find it in the stock tune. You can see the transition by observing the fuel trims. As soon as you see the short term trims fluctuating it's in closed loop. I'd guess that you already know that but I'll add it anyway.

 

[ExSRT8Guy]

I'd guess that you already know that but I'll add it anyway.

Actually, I didn't. Thanks for the heads up!

 

[nasty281]

I thought it had to do with the temp of the o2 sensor not coolant?

 

[Swarzkopf]

Nope - what I posted is right out of a stock '05 GT file.

It probably delays to allow the O2 sensor to heat up, but the delay is based on ECT and time.

 

[BruceH]

I thought it had to do with the temp of the o2 sensor not coolant?

Nope - what I posted is right out of a stock '05 GT file.

It probably delays to allow the O2 sensor to heat up, but the delay is based on ECT and time.

It kind of does. It won't go into closed loop until the front 02 is at least 500 degrees. The time and temp is the absolute minimum time provided that all of the other requirements are met. Some of those requirements are buried in the tune.

The o2 requirements are located in the open-closed loop scalar.