3.7 retune
08-21-2016, 01:49 PM
#1
3rd Gear Member
Thread Starter
Join Date: Oct 2014
Location: MD
Posts: 625
3.7 retune
hey guys just wondering, had my bama tune in since last nov- 2015, and noticed performance and gas mileage going downhill, the last couple months, so i took it out and reprogrammed, what a difference, back where it was, have you 3.7 guys had to do this? I know if you dyno tune you have to do this, so I guess same thing
08-21-2016, 05:23 PM
#2
2nd Gear Member
Join Date: Mar 2008
Location:
Posts: 246
I haven't had this happen yet Choppertwo, but I have heard of it happening on other cars and tunes. The issue basically comes down to the adaptive parameters in the car's ECU. With some tunes, when the adaptives start doing their thing, the interaction between the adaptive parameters and the tune doesn't work out.
FWIW - If that were to happen to you again and if your tuner hardware or software will let you, just reset the adaptive parameters rather than reflash the whole thing. You'd get the same effect, possibly with less time invested.
FWIW - If that were to happen to you again and if your tuner hardware or software will let you, just reset the adaptive parameters rather than reflash the whole thing. You'd get the same effect, possibly with less time invested.
08-21-2016, 08:11 PM
#3
3rd Gear Member
Thread Starter
Join Date: Oct 2014
Location: MD
Posts: 625
I haven't had this happen yet Choppertwo, but I have heard of it happening on other cars and tunes. The issue basically comes down to the adaptive parameters in the car's ECU. With some tunes, when the adaptives start doing their thing, the interaction between the adaptive parameters and the tune doesn't work out.
FWIW - If that were to happen to you again and if your tuner hardware or software will let you, just reset the adaptive parameters rather than reflash the whole thing. You'd get the same effect, possibly with less time invested.
FWIW - If that were to happen to you again and if your tuner hardware or software will let you, just reset the adaptive parameters rather than reflash the whole thing. You'd get the same effect, possibly with less time invested.
08-22-2016, 05:21 AM
#4
2nd Gear Member
Join Date: Jul 2012
Location: Clinton, Tennessee
Posts: 375
hey guys just wondering, had my bama tune in since last nov- 2015, and noticed performance and gas mileage going downhill, the last couple months, so i took it out and reprogrammed, what a difference, back where it was, have you 3.7 guys had to do this? I know if you dyno tune you have to do this, so I guess same thing
08-22-2016, 11:34 AM
#6
3rd Gear Member
Join Date: Dec 2006
Location: Colorado
Posts: 944
You're not imagining it.
I have an old bama 87 octane performance tune that I like as a DD.
My shift pressures get weaker and weaker over time.
I don't like reprogramming every couple months, I keep thinking sooner
or later something will go wrong with the download.
I disconnect the battery for a few minutes every couple months instead.
There's some procedure I saw on this forum you can try with the ignition switch, gas pedal, watching the idiot lights and so forth. I tried it but it didn't work for me.
I have an old bama 87 octane performance tune that I like as a DD.
My shift pressures get weaker and weaker over time.
I don't like reprogramming every couple months, I keep thinking sooner
or later something will go wrong with the download.
I disconnect the battery for a few minutes every couple months instead.
There's some procedure I saw on this forum you can try with the ignition switch, gas pedal, watching the idiot lights and so forth. I tried it but it didn't work for me.
08-22-2016, 01:56 PM
#7
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
That loss of power feeling is probably a combination of things (heat from summer), different gas mixture for summer vs winter and some of the adaptive learning. Although the adaptive learning shouldn't be an issue if you drive it very similar every day.
Heat in the summer causes the engine to retard timing significantly more to keep the engine and emissions within a certain range. The more timing it retards (pulls) the less power you make. Retarding the timing also prevents pinging which is preignition and can damage a motor.
When was the last time your air and fuel filters were replaced? Check your plugs for uneven wear. That's about all you can do until mother nature starts to drop the temps.
Heat in the summer causes the engine to retard timing significantly more to keep the engine and emissions within a certain range. The more timing it retards (pulls) the less power you make. Retarding the timing also prevents pinging which is preignition and can damage a motor.
When was the last time your air and fuel filters were replaced? Check your plugs for uneven wear. That's about all you can do until mother nature starts to drop the temps.
Last edited by Derf00; 08-23-2016 at 02:46 PM.
08-22-2016, 09:24 PM
#8
2nd Gear Member
Join Date: Mar 2008
Location:
Posts: 246
Yeah, let me try to explain a bit more....
Back in the early days of electronic engine controls the timing to apply and the fuel to inject were fixed numbers. Look up the engine load (or throttle position) and the RPM, get the timing and fuel quantity to inject. Pretty easy. And about all that could be accomplished with a automotive computer with the brains of a thermostat.
Fast forward a little bit and we figure out that timing and fuel quantity are relative things. Ironically, some older mechanical fuel injection systems "understood" that if the atmospheric pressure was off a bit, you'd want to inject a little more or less, or flex the timing a bit (remember vacuum advance?). Early engine electronic control modules (ECMs) weren't smart enough to do that, so the early electronically controlled cars didn't work all that well. Think GM's "Crossfire" (or "Ceasefire") injection system, or Ford's early stuff on the turbo four cylinders. They were new! They were cool! And they sucked! Tremendously!
Especially when compared to a well tuned mechanical setup that adapted to conditions.
Now the wire weenies learn real quick, so they figured out that what THEY needed was a way to adapt to changing conditions too. They implemented this by keeping the original "look up the number" system but then added an adjustment that got updated every so often. Fast forward to today, and it can be updated as often as every injection cycle. (See, they DO learn quick.
)
So when we talk about adaptive parameters, we're talking about the part of the ECM that is allowed to change over time. Put in crappy gas? Retard the timing with the adaptive parameter until the engine knock sensor stops whining. Engine spending lots of time at high load? Advance the timing a bit. And so on.
So you don't need to reload the whole tune, just flush the "adaptives" to get back to the basic tune's goodness.
What's next? It's becoming increasingly common to have the transmission and the engine talk to each other and share adaptation strategies. If the engine is backing off timing because the fuel being used is just this side of donkey wee, the engine ECM can tell an automatic transmission ECM whats up and then the transmission can alter the shift points too. OR you can implement very useful tricks like launch control to extract every last ounce of power and get it to the pavement rather than up in smoke. Not that that isn't good too...
...but it's not always the fastest way from point A to point B.
Hope this helps!
Back in the early days of electronic engine controls the timing to apply and the fuel to inject were fixed numbers. Look up the engine load (or throttle position) and the RPM, get the timing and fuel quantity to inject. Pretty easy. And about all that could be accomplished with a automotive computer with the brains of a thermostat.
Fast forward a little bit and we figure out that timing and fuel quantity are relative things. Ironically, some older mechanical fuel injection systems "understood" that if the atmospheric pressure was off a bit, you'd want to inject a little more or less, or flex the timing a bit (remember vacuum advance?). Early engine electronic control modules (ECMs) weren't smart enough to do that, so the early electronically controlled cars didn't work all that well. Think GM's "Crossfire" (or "Ceasefire") injection system, or Ford's early stuff on the turbo four cylinders. They were new! They were cool! And they sucked! Tremendously!
Especially when compared to a well tuned mechanical setup that adapted to conditions.Now the wire weenies learn real quick, so they figured out that what THEY needed was a way to adapt to changing conditions too. They implemented this by keeping the original "look up the number" system but then added an adjustment that got updated every so often. Fast forward to today, and it can be updated as often as every injection cycle. (See, they DO learn quick.
)So when we talk about adaptive parameters, we're talking about the part of the ECM that is allowed to change over time. Put in crappy gas? Retard the timing with the adaptive parameter until the engine knock sensor stops whining. Engine spending lots of time at high load? Advance the timing a bit. And so on.
So you don't need to reload the whole tune, just flush the "adaptives" to get back to the basic tune's goodness.What's next? It's becoming increasingly common to have the transmission and the engine talk to each other and share adaptation strategies. If the engine is backing off timing because the fuel being used is just this side of donkey wee, the engine ECM can tell an automatic transmission ECM whats up and then the transmission can alter the shift points too. OR you can implement very useful tricks like launch control to extract every last ounce of power and get it to the pavement rather than up in smoke. Not that that isn't good too...
...but it's not always the fastest way from point A to point B.Hope this helps!
08-23-2016, 05:59 AM
#9
3rd Gear Member
Thread Starter
Join Date: Oct 2014
Location: MD
Posts: 625
o when we talk about adaptive parameters, we're talking about the part of the ECM that is allowed to change over time. Put in crappy gas? Retard the timing with the adaptive parameter until the engine knock sensor stops whining. Engine spending lots of time at high load? Advance the timing a bit. And so on. So you don't need to reload the whole tune, just flush the "adaptives" to get back to the basic tune's goodness.
What's next? It's becoming increasingly common to have the transmission and the engine talk to each other and share adaptation strategies. If the engine is backing off timing because the fuel being used is just this side of donkey wee, the engine ECM can tell an automatic transmission ECM whats up and then the transmission can alter the shift points too. OR you can implement very useful tricks like launch control to extract every last ounce of power and get it to the pavement rather than up in smoke. Not that that isn't good too......but it's not always the fastest way from point A to point B.
Hope this helps![/QUOTE]
but how do I do this without retuning?
So you don't need to reload the whole tune, just flush the "adaptives" to get back to the basic tune's goodness.What's next? It's becoming increasingly common to have the transmission and the engine talk to each other and share adaptation strategies. If the engine is backing off timing because the fuel being used is just this side of donkey wee, the engine ECM can tell an automatic transmission ECM whats up and then the transmission can alter the shift points too. OR you can implement very useful tricks like launch control to extract every last ounce of power and get it to the pavement rather than up in smoke. Not that that isn't good too...
...but it's not always the fastest way from point A to point B.Hope this helps![/QUOTE]
but how do I do this without retuning?
08-23-2016, 02:48 PM
#10
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
o when we talk about adaptive parameters, we're talking about the part of the ECM that is allowed to change over time. Put in crappy gas? Retard the timing with the adaptive parameter until the engine knock sensor stops whining. Engine spending lots of time at high load? Advance the timing a bit. And so on. So you don't need to reload the whole tune, just flush the "adaptives" to get back to the basic tune's goodness.
What's next? It's becoming increasingly common to have the transmission and the engine talk to each other and share adaptation strategies. If the engine is backing off timing because the fuel being used is just this side of donkey wee, the engine ECM can tell an automatic transmission ECM whats up and then the transmission can alter the shift points too. OR you can implement very useful tricks like launch control to extract every last ounce of power and get it to the pavement rather than up in smoke. Not that that isn't good too......but it's not always the fastest way from point A to point B.
Hope this helps!
So you don't need to reload the whole tune, just flush the "adaptives" to get back to the basic tune's goodness.What's next? It's becoming increasingly common to have the transmission and the engine talk to each other and share adaptation strategies. If the engine is backing off timing because the fuel being used is just this side of donkey wee, the engine ECM can tell an automatic transmission ECM whats up and then the transmission can alter the shift points too. OR you can implement very useful tricks like launch control to extract every last ounce of power and get it to the pavement rather than up in smoke. Not that that isn't good too...
...but it's not always the fastest way from point A to point B.Hope this helps!
You pull the negative battery cable off the battery and let it sit for at least 30 minutes. If you don't wait long enough, there is still a backup charge in the PCM that keeps the memory and it won't clear out the adaptive learning.
