First off, if you have an '07+, you do have to plug your O2 bungs if you use PCIII.


Dynas got O2 sensors in '07...I'm no expert, but as I understand it the stock O2 sensor setup is very narrowband...if you're close to your target AFR you'll be ok, but they won't fix it if you aren't.

For example, I swapped my stock pipes for a Thunderheader, and figured I'd see how XIEDs would work with no Stage I A/C change. I got a lot of popping over the hour or two I was out testing it, and the O2 sensors never seemed to account for it or adjust, even though the XIEDs had richened the mixture.




The Thundermax setup I subsequently installed (with Stage I A/C) has wider band O2 sensors that replaced the stockers, and that paired with the Autotune module has made for great riding in the couple days I've used it. With Thundermax I plug in a canned map, and the O2/Autotune accounts for any problems...it essentially improves your setup the more you ride.

Initially, I had minor popping only at certain RPMs on the decel, and those have already gone away. For me, there's no choice but the TMax.....the only other thing I'd have gone with would have been TTS, and I wouldn't even consider something that would have me running open loop.

 

Bingo. To me the extra money you pay is worth avoiding issues later. I don't like having to do things more than once, so before you go buying use the search function.

 

no,there is no mass air flow or manifold pressure sensor,that is the problem,the adjustments are based on throttle position,cyl. head temp.and and 02 input the ecm is programmed for a value based on these.it "assumes how much air is coming in to motor based on programming in the ecm.this is why it is too lean with a a/c upgrade.there is more air coming in,but the ecm does'nt realize it,and can't add more fuel accordingly.please correct me if i'm wrong.

 

Archer,
Thanks for your reply.I understand the basic function now. To all, if I just am adding slip on mufflers,an a/c upgrade and then decide to run open loop, can I do damage to the motor.?? I plan no future engine mods, just looking for a little more performance, sound, and to have engine run a little cooler. Thanks in advance!!

 

Do you mean open-loop as in using PCIII or FuelPak? That'd be fine.

 

Guys, I'm not the original poster but I want to say thanks to all of you who have contributed to this thread. I too am looking for a few upgrades in the future and this info helps a lot.

 

robert, are you talking about the HD EFI-Equipped models??
Stock ECM, or a piggybacked tuner??

The stock ECM does not *assume* anything
(to the best of my knowledge)

From the manual.........

ESPFI System Operation

CKP Sensor – Crank Position Sensor
TP Sensor – Throttle Position
MAP Sensor - Manifold Absolute Pressure
IAT Sensor – Intake Air Temperature

When the engine is running the series of events typically follows the process below:

* The ECM monitors the CKP, TP, IAT & MAP sensors
telling it engine rpm, throttle position, intake air temperature and manifold absolute pressure.

* The ECM looks at throttle position and engine rpm when it refers to the VE Look-up tables.
From this information the ECM knows the volume of air that should be entering each cylinder at this moment,
under these present conditions.

* At the same time the ECM looks at intake air temperature and manifold absolute pressure
to calculate the density of the air entering the engine.
Air density tells the ECM how much oxygen is in the air entering the engine.

* Now the ECM knows exactly how much oxygen is entering each cylinder
and it refers to the AFR Look-up table for the AFR that’s desired.
It then sends the appropriate output signals to the fuel injectors
to achieve the AFR it has been programmed to deliver
for the current engine rpm and engine load.

* The ECM also refers to the Spark Advance Look-up tables
for the desired spark advance for each cylinder
according to the current engine rpm and engine load.
The ECM then sends output signals to the front and rear ignition coils
to deliver the desired timing of the spark for each cylinder.
.

 

thanks,Mud that cleared up a lot,and I stand corrected.

 

mud
Good explanation, thanks.
What I missing from what you said is where the narrow band o2 sensors come into the picture you described.
Only trying to learn, if I missed it in an earlier post, my bad.
TIA

 

hawk, it's all very complicated,
and I certainly do not fully understand it all, or even come close.

So, for what it's worth..............

The way I think they work is only when in closed loop
to make slight adjustments.

From the Race Tuner manual again
(the red high Lighting below is mine)..........

**************************************************
Model Year 2006 vehicle changes include a new throttle body and injectors,
and closed-loop fuel control on Dyna EFI models.

Closed-Loop Operation Background 2006 EFI Dyna models come equipped with 2 “switching” sensors…
also known as stoichiometric sensors.

Unlike wide-band sensors which can measure and control over a wide AFR range (10-20),
switching sensors can only control within a narrow range (+/- 0.5 AFR).

This offset in control is accomplished with the EFI Race Tuner by adjusting the Closed-Loop Bias table.

Closed-loop operation is only used when the engine is in a normal operating condition.

There are several instances when the ECM goes into open-loop operation.

These include: warm-up, high load or high RPM operating conditions (such as WOT),
when the vehicle is in Hot Engine Management,
or any time the AFR requested is richer than 14.6.
**********************************************
.
screenshot below is the current Air/Fuel table for my 121
(always richer than 14.6)
.
.

.
.


.