300% duty cycle on IAC?
2 Attachment(s)
I have been trying (without success) to tune my idle for the past week or so. I think there might be something wrong with the valve, or the wiring, or something (it honks, but that's for another day). But today it started doing this thing that makes no sense at all.
Driving along, it will act normal, then if I go into boost and go back to regular driving, I get weird pulses and the IAC duty cycle starts climbing. I marked the behavior in the attached log. I have no idea what is going on. Has anybody seen this before? |
Nevermind, misread
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If I'm reading the MSQ correctly, your firmware version is MS3 pre-1.1 beta 20. That is an antique beta firmware. I'd definitely upgrade the firmware before trying anything else.
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Originally Posted by Skamba
(Post 1573237)
If I'm reading the MSQ correctly, your firmware version is MS3 pre-1.1 beta 20. That is an antique beta firmware. I'd definitely upgrade the firmware before trying anything else.
Honestly I've been dreading a firmware update because I'm afraid I'll have to retune a lot, but I can only assume it will be better after the update. |
Originally Posted by skidude
(Post 1573240)
That is probably correct. I set the car up years ago, tuned it well enough for most things, then just drove it.
Honestly I've been dreading a firmware update because I'm afraid I'll have to retune a lot, but I can only assume it will be better after the update. |
Originally Posted by shuiend
(Post 1573243)
1.1 is so old. You need to get into the latest 1.4 or 1.5 if you want to play with engine states.
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I was able to find the following high level changes between various versions:
MS3 1.5 firmware Key changes and Gotchas - from 1.4.x and earlier ======================= 1. Engine states These must be configured for idle, overrun, idle VE, idle advance. 2. Dome control. Initial test implementation now replaced by implementation integrated with regular boost control. New table settings will be required. 3. Fan control. New settings for TPS and VSS shutoff. 4. A/C idleup. New settings for TPS, VSS and RPM shutoff. 5. Internally the handling of I/O pins has changed. 6. Nitrous progressive VSS and time based - **fuel adder handling changed** 7. Noise filter internal logic changed. MS3 1.4 firmware Key changes and Gotchas - from 1.3.x and earlier ======================= 1. Baro Previously the code used to divide by the barometer when calculating the fuel pulsewidth. If using an old tune you need to enable the "old style" baro calculation to enable the old behaviour. 2. CLT rev limiter The TPS bypass rev limit setting has been removed, the standard hard limit is now used in bypass mode to reduce confusion. 3. Closed-loop boost The initial values table is now a bias table. This needs to be tuned as an open-loop table using "setup mode" before enabling full closed-loop. See the tooltips and manual. 4. On/Off outputs using bitwise AND The meaning of threshold and hysteresis has changed, see the manual. 5. Other changes are covered in the Setting Up manual. Key changes and Gotchas - from 1.2.x and earlier ======================= 1. Idle control settings re-arranged Need to reset: Stepper vs. PWM idle valve Open-loop vs. Closed-loop Output pin for PWM. 2. Closed-loop idle control The settings are re-arranged to simplify setup, but existing users will need to retune. 3. GM/TFI ignition settings changed. 4. MAF configuration changed. 5. VSS input configuration changed. 6. Generic PWM output type and frequency selection changed. 7. On/Off outputs enabling changed. 8. Various tables now use "kPa" instead of "%", the numbers should be ok. 9. VVT adds min/max duty settings, you may want to use them. 10. Two TunerStudio dash indicators have been renamed: Not Synced -> Not RPM Synced Half-sync -> Half-RPM sync You will need to re-load you dash (right-click on a blank area of the dash select Load/Save, then Load dashboard, then Accept) or update manually. 11. Rev limiting is changed. Check your settings. 12. Some "trigger wheel" users may need to change their tooth#1 angle if it was close to 360deg or 720deg. (A previous bug was fixed.) Key changes and Gotchas - from 1.1.x and earlier ======================= 1. MAF There is a new MAF calibration implementation like MS3. The old method is still valid. 2. Baro The default settings for baro were on the MAP sensor calibration page as 147, -47 with a tweak curve on top. The new method sets these two numbers to zero and exclusively uses the adjustment curve. 100% means un-altered fuelling. 3. Air-density In previous versions, there was an internal calculation for air density with a tweak curve on top. The new method exclusively uses the adjustment curve. 100% means un-altered fuelling. Note: MAT does change air density and the speed-density equation relies on this to estimate intake charge. 4. Spark output polarity The name has been simplified "Going High" - was called "Going High (Inverted)" "Going Low" - was called "Going Low (Normal)" DOUBLE CHECK YOUR SETTING BEFORE CONNECTING COILS. 5. Boost Control To make things more intuitive we have now changed the firmware so that - "Normal" is the most typical output polarity setting - larger boost duty% numbers mean more boost. If you are a new user starting out from scratch, then nothing needs to be changed, just use the default settings. If you are upgrading from a previous firmware version, then the Boost Output polarity setting will be the opposite. For most users it will now be "Normal". This is true whether using open- or closed-loop boost control. If you're using closed-loop, nothing else should need to change. Open loop boost users most likely need to set their table so that: new_cell_value = 100 - old_cell_value Remembering that more duty = more boost. 6. Serial protocol The firmware now uses the "newserial" protocol. This requires compatible tuning software and firmware loaders. (Note, it you want to revert to an older firmware version you will need to use the new firmware loader, or use the boot jumper.) |
Originally Posted by Skamba
(Post 1573246)
I was able to find the following high level changes between various versions:
Engine states is the big addition in the 1.5.* firmwares. It's basically a smarter way of identifying whether you are decelerating, idling, accelerating, etc, and selecting the right behavior based on that. Generally it makes transitions between these states more fluent. I've just updated to 1.5.2 RC11 last week, and it seems to work a bit more smoothly than 1.4.1, although it's not terribly different. Now if I can just figure out how to make my IAC valve stop honking. It's obnoxious and sounds like I have a goose trapped in the engine bay. |
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