PWM idle up for no reason
#1
PWM idle up for no reason
My idle valve is closed @ 26% and fully open @ 65%
You can see in the pic that the valve just moved from closed (26%) to 45.1% (cracking value @ this CLT)
I can't understand why it's happening, can you help out ?
Thanks !
Last edited by elior77; 10-31-2014 at 02:34 PM.
#3
Retired Mech Design Engr
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From: Seneca, SC
Closed Loop Idle Settings:
Close Delay set at 1 sec; Leave Valve Closed Above 1000 RPM; For the # of sec = 3
So, 1 second after you leave CL idle plus about 200 RPM, your idle valve will close. Then, as in during a shift, you go back to closed throttle, then, after 3 seconds OR RPM falls below 1000 RPM, the idle valve opens to the target value. This is needed to hold RPM up until CL can be activated.
In this case, it looks like you *EDIT* hit the 3 seconds.
i.e. it is doing this because you told it to.
*EDIT* 1000 RPM seems low, as it is real close to idle.
Close Delay set at 1 sec; Leave Valve Closed Above 1000 RPM; For the # of sec = 3
So, 1 second after you leave CL idle plus about 200 RPM, your idle valve will close. Then, as in during a shift, you go back to closed throttle, then, after 3 seconds OR RPM falls below 1000 RPM, the idle valve opens to the target value. This is needed to hold RPM up until CL can be activated.
In this case, it looks like you *EDIT* hit the 3 seconds.
i.e. it is doing this because you told it to.
*EDIT* 1000 RPM seems low, as it is real close to idle.
#8
Retired Mech Design Engr
iTrader: (3)
Joined: Jan 2013
Posts: 5,012
Total Cats: 859
From: Seneca, SC
I don't know about your first 2 questions, but they are good ones, and I too would like to know what all of those status and port values mean.
But to the third, yes, and that is what I tried to convey in my first response. If you set the Closed Delay to "0" in the section I referred to (Leave Closed.... etc) then the Idle Valve will stay open all of the time to exactly where your target table tells it to be. Cycle the ignition off and back on for this to be stabilized.
Then there is no, why is it open, why is it closed. It will always be open and ready.
But to the third, yes, and that is what I tried to convey in my first response. If you set the Closed Delay to "0" in the section I referred to (Leave Closed.... etc) then the Idle Valve will stay open all of the time to exactly where your target table tells it to be. Cycle the ignition off and back on for this to be stabilized.
Then there is no, why is it open, why is it closed. It will always be open and ready.
#12
Retired Mech Design Engr
iTrader: (3)
Joined: Jan 2013
Posts: 5,012
Total Cats: 859
From: Seneca, SC
OP. If you change your mind, post up and I can put together shots of all the pertinent screens, and possibly some further explanation
Basically, the idle valve has to open BEFORE CL so that the RPM's will settle above your target CL RPM so that the algorithm can see stability and engage. Then CL takes control.
Basically, the idle valve has to open BEFORE CL so that the RPM's will settle above your target CL RPM so that the algorithm can see stability and engage. Then CL takes control.
#14
I think your issue has to do with the max decel load% value.
on your log screenshot, you're idling well below 29 MAP (most people idle closer to 30-32MAP). That value should be tuned to be just a few points below what you typically idle at. It appears once your vacuum drops below that threshold it finally enters PID momentarily, after the 5sec delay you have set. Otherwise the car wont enter into PID unless you've breached the max load, and then come back above it.
I'd tune the max load value better, and try a delay of only 1sec. That's what I always used with much success.
and then I'd actually close my TB screw so the car actually enters RPMs in which the MS will control idle at. Right now your idle valve isn't doing a damn thing at 20%PWM or 60%PWM.
on your log screenshot, you're idling well below 29 MAP (most people idle closer to 30-32MAP). That value should be tuned to be just a few points below what you typically idle at. It appears once your vacuum drops below that threshold it finally enters PID momentarily, after the 5sec delay you have set. Otherwise the car wont enter into PID unless you've breached the max load, and then come back above it.
I'd tune the max load value better, and try a delay of only 1sec. That's what I always used with much success.
and then I'd actually close my TB screw so the car actually enters RPMs in which the MS will control idle at. Right now your idle valve isn't doing a damn thing at 20%PWM or 60%PWM.
#16
Braineack: I idle @28-30kpa
Went for a drive yesterday and I'm very happy
CL is working brilliantly !
EGO correction and ignition idle advance works great too.
I'm very happy, I can sleep now
Key points that made the difference:
- Idle AFR @ 13.5:1 (850rpm)
- CL idle, "Use Last Value Or Table: Use Initial value table (CLT)"
- Add spark when rpm below idle rpm
For a 40km drive (20km each way) all looked super great to me.
Thanks for the help guys, success story on the way
Went for a drive yesterday and I'm very happy
CL is working brilliantly !
EGO correction and ignition idle advance works great too.
I'm very happy, I can sleep now
Key points that made the difference:
- Idle AFR @ 13.5:1 (850rpm)
- CL idle, "Use Last Value Or Table: Use Initial value table (CLT)"
- Add spark when rpm below idle rpm
For a 40km drive (20km each way) all looked super great to me.
Thanks for the help guys, success story on the way
Last edited by elior77; 11-05-2014 at 09:09 AM.
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