I have the 165 ecm (MAF) using 6e and a wb o2. I wanted to try running and tuning in open loop using tunerpro and tunercat. Checked several posts but never really found an answer to this question. Which tables do you use to tune in open loop? I only see two that mention open loop and thay appear to be only cooling temp and load corrections. Are these the tables that are used or are all the tables active in open loop?
Buy open loop I mean to increase coolant temp to max for closed loop engage and lock the blm and int scales at 128.

 

MAF tables can be tuned while in open loop. Adjust them to have the WB indicated AFR match the desired (or commanded) AFR. Be aware that cams with a lot of overlap can skew the WB readings at low engine speeds.

The desired AFR can also be changed for the best driveability, mileage, and performance.

RBob.

 

Just to be clear, or re-enforce my lack of tuning skill via the chip burn, unless the table or parameter addresses closed loop specifically, it can be used in open loop, correct?
Also I know that in the constants I believe, you can select what you want the AFR to be, example 14.7. This parameter will have no effect in open loop with the blm/int's locked, correct?

Thanks for the help!!

 

The closed loop tables such as INT delay, proportional gains/delays, O2 error limits will not have any affect in open loop.

The stoich value will. This is because the open loop desired AFR is based on a percentage change from the stoich term. There is an AFR % change based on LV8 (load variable) and another based on coolant. While in open loop the stoich term and the two tbales form a new desired AFR ratio.

I believe the PE AFR is the same way. Based as a percentage change from the stoich term.

RBob.

 

Thanks again for the help! I am sure that this new tuning direction will broaden and enrich my tuning skills. If I run into major problems I can always go back to closed loop.
I need to sharpen my skills on my basically stock motor because I have a 406 on the stand that is going to get the HSR vortec setup, and I am sure that will push me to my limits!

 

I'm starting to do some open loop tuning of my own. I bought a Zeitronix ZT-2, and made a voltage divider circuit to bring the 5V wideband output down to 1V. I'm feeding that directly into the ECM while I run in open loop mode. I have it setup so I can swap a jump and feed the ZT-2's simulated narrowband into the ECM when put a closed loop PROM in.

So I'm capturing the WB readings with my trusty old Diacom and I'm calculating VE changes based on the WB's measured AFR verse the ECM requested AFR.

I want to make sure that I'm not missing anything or reading anything into what RBob has said.

The ECM's requested AFR includes any adjustments that the open loop tables require, correct? So the Open Loop Change to Air/Fuel vs Coolant Temp and the Open Loop Change to A/F vs MAP are both included in the ECM's requested AFR?

And the ECM is reading the VE table as the 14.7 values and adjusting the Injector Pulse Width to try to compensate for requested AFRs that are not 14.7?

So, I can simply tune by comparing the ECM's request AFR with the measured AFR and calculating a % change to the corresponding VE cells, right?

Joe
92 Z28
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