djd24

Hey everyone,

I have a 99 eclipse gsx 5spd with an evo8 ecu. I've had this set up for about 5 years, and it's been running great. I've recently re-installed my A/C system, and am now experiencing two idle-related issues. The first issue is that idle with the A/C on will not stabilize. It will just stumble back and forth from 500-1,000 until it eventually stalls. Second issue is that whenever I go off throttle, causing the rpms to drop fast, the car just dies. Neither one of these issues happen with my A/C off.

I'm running Tephramods v7 96530706 with speed density. Below are all my idle tables. Does anyone have a direction to point me in? Thanks in advance.

boostin4kix

Have you tried cranking up idle error ac on? I noticed it only corrects about 4 steps with 250 rpm error. Try to ramp it up to around 8 or 10 steps and see if it makes a difference. You might also try raising the Desired ISCV AC On Neutral a few steps or so at the higher temperature cells. Good luck, and let us know how it turns out

djd24

No, I have not tried adjusting either of those tables. Admittedly, this is one section of the ecu I know very little about. I just flashed over those changes this morning, will drive it for a few days, then report back. Thanks for the advice!

djd24

So, after just a bit of driving with those adjustments, I can tell it's no better.

I did neglect to leave out one important bit of info. Both the idle stability and stalling after acceleration get worse the more I drive it. For example, after running the car for 10-15 min, coolant temps will be around 205-210, and idle with A/C on will be stable. Also, stalling will be unlikely. But, as I drive the car, it gets progressively worse. So, maybe 30 min later, coolant temps will still be 205-210 (maybe slightly higher), but now idle with A/C on is all over the place, and it will stall all the time.

It's almost like the ECU is trying to correct for something over time, but making the wrong correction.

Any other ideas?

boostin4kix

Have you logged your IAT temps?

djd24

I haven't, but that's a good call. I'm wondering if that "High Intake Air Temp ISCV Increase" table is the issue. It's currently set to '0' for AC off, and '20' for AC on.

djd24

One thing that seems a bit suspect to me is my 3D Idle Motor Stepper Lookup Table. I'm noticing that all the cells on the Y axis greater than 93.8 have no color. From my experience, those white cells can typically mean you're calling on a value outside the bounds of that table. After researching a bit more, I see that some people with my definition file running tephra v7 have either "% Demand" or "RPM" as the y-axis value. I'm wondering if somehow my axis value is wrong, and I should be using "% Demand" instead of "Load." Below is the relevant section of code from my TephraMOD-96530706-v7 xml. Any thoughts?


<table name="Idle Stepper Look up Table" category="Idle" address="43ab" type="3D" scaling="ISCVSteps">
<table name="Coolant Temp" address="6b0a" type="X Axis" elements="8" scaling="Temp"/>
<table name="Load" address="6b24" type="Y Axis" elements="27" scaling="Load16"/>
</table>

boostin4kix

I do have two Idle Stepper Look Up Tables. The first one is basically the same as yours as far as I can tell, but the second one uses ISCV Demand as the Y axis. Maybe you can add that bit to your xml and make some changes on it?

<table name="Idle Stepper Look up Table" scaling="ISCVSteps" type="3D" address="43ab" category="Idle">

<table name="Coolant Temp" scaling="Temp" type="X Axis" address="6b0a" elements="8"/>

<table name="Load" scaling="Load16" type="Y Axis" address="6b24" elements="27"/>







-<table name="Idle Stepper Lookup Table" scaling="ISCVSteps" type="3D" address="43ab" category="ISCV Control">

<table name="Coolant Temp" scaling="Temp" type="X Axis" address="6b0a" elements="8"/>

<table name="ISCV Demand" scaling="ISCV_AX2_16" type="Y Axis" address="6b24" elements="27"/>