The S2000, TP, CEL Fix, and Closed Loop Operation.
05-18-2015, 08:00 AM
#1
The S2000, TP, CEL Fix, and Closed Loop Operation.
Hello all,
Fairly new here and just became the proud owner of a MY03. I'm currently looking at upgrading my current exhaust system and going with either a TP or HFC. From what I understand the S2000 ECU can be a bit finicky, and in the interest of protecting the motor, it tends to run the car on the richer side of things. That said, I'd like to know if anyone has any real world experience with the closed loop operation of this car when running a CEL fix with their test pipe. Witnessed AFR's vs. recycled internet babble.
Here's my concern, replacing the cat with a TP - this will result in a rich condition on any car and as such modern ECU's will allocate the proper fuel and timing adjustments to get things running correctly. In this scenario, the AP1 ECU should spot the much richer condition and lean the car out a bit, in turn optimizing performance.
Now let's say we add a CEL fix to this mix and get rid of that pesky yellow light. Isn't this now telling the ECU that everything is OK and not to make any adjustments? Therefore resulting in a car that already runs slightly rich not being leaned out and thus hindering the performance of the vehicle?
My general conclusion is that it's either best to run a TP with no CEL fix and essentially let the ECU do it's own closed loop "tuning" to correct the rich condition and optimizing performance, while having to look that CEL in the face every day. Or going with an HFC at the cost of a minor decrease in performance from a TP while not triggering a CEL and letting the ECU once again do it's thing to optimize performance during closed loop.
In short, I'm simply against the use of a CEL fix and tricking the ECU to think that the motor is running fine, when in reality it's moving air through a much larger, unrestricted pipe and not doing anything to account for it.
All this said, I don't think I'm entirely right here. There's definitely room for error in my thought process and I'd really like to kick these thoughts and ideas around with you folks! Just wanted to include for arguments sake, that I'm fully aware the the addition of larger exhaust diameter/unrestricted cat doesn't actually create a rich or lean condition. But it will in fact tell your 02 that there's one. In the same fashion that an exhaust leak will trigger lean, and a bad cat will trigger rich. I'm also fully aware that we're talking nickel and dimes here when it comes to the minor gains and losses that would be seen. Doesn't change the fact that I'd prefer optimal running conditions vs. something less beneficial than OEM.
- Steph
Fairly new here and just became the proud owner of a MY03. I'm currently looking at upgrading my current exhaust system and going with either a TP or HFC. From what I understand the S2000 ECU can be a bit finicky, and in the interest of protecting the motor, it tends to run the car on the richer side of things. That said, I'd like to know if anyone has any real world experience with the closed loop operation of this car when running a CEL fix with their test pipe. Witnessed AFR's vs. recycled internet babble.
Here's my concern, replacing the cat with a TP - this will result in a rich condition on any car and as such modern ECU's will allocate the proper fuel and timing adjustments to get things running correctly. In this scenario, the AP1 ECU should spot the much richer condition and lean the car out a bit, in turn optimizing performance.
Now let's say we add a CEL fix to this mix and get rid of that pesky yellow light. Isn't this now telling the ECU that everything is OK and not to make any adjustments? Therefore resulting in a car that already runs slightly rich not being leaned out and thus hindering the performance of the vehicle?
My general conclusion is that it's either best to run a TP with no CEL fix and essentially let the ECU do it's own closed loop "tuning" to correct the rich condition and optimizing performance, while having to look that CEL in the face every day. Or going with an HFC at the cost of a minor decrease in performance from a TP while not triggering a CEL and letting the ECU once again do it's thing to optimize performance during closed loop.
In short, I'm simply against the use of a CEL fix and tricking the ECU to think that the motor is running fine, when in reality it's moving air through a much larger, unrestricted pipe and not doing anything to account for it.
All this said, I don't think I'm entirely right here. There's definitely room for error in my thought process and I'd really like to kick these thoughts and ideas around with you folks! Just wanted to include for arguments sake, that I'm fully aware the the addition of larger exhaust diameter/unrestricted cat doesn't actually create a rich or lean condition. But it will in fact tell your 02 that there's one. In the same fashion that an exhaust leak will trigger lean, and a bad cat will trigger rich. I'm also fully aware that we're talking nickel and dimes here when it comes to the minor gains and losses that would be seen. Doesn't change the fact that I'd prefer optimal running conditions vs. something less beneficial than OEM.
- Steph
05-18-2015, 08:15 AM
#2
Yes there are errors in your thoughts 
The CEL fix only affects the secondary O2 sensor and that sensors only task is to check if the cat is working correctly.
CEL fix or not, it will not influence the fueling at all.
The CEL fix only affects the secondary O2 sensor and that sensors only task is to check if the cat is working correctly.
CEL fix or not, it will not influence the fueling at all.
05-18-2015, 08:25 AM
#3
Wow man, I really need to lay off the reefer. It never even dawned on me that this car has a primary/secondary 02 sensor set up. I've been dealing with OBD1 cars for so long that it wasn't even a thought in my mind! That makes perfect sense and I'm extra happy that you cleared the air for me immediately, was beginning to lose sleep!
Thread
Thread Starter
Forum
Replies
Last Post
c32b
S2000 Engine Management
4
03-16-2012 09:25 AM
Rdriver
S2000 Under The Hood
7
03-19-2003 06:46 PM
