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namre

Idle Problems

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I have strange idle behaviors. It seems normal under 1000 RPM but can you please help on the following issues?

  1. My idle target table and base positions are all set. However when I first start the car, idle speed control does not come active. Idle stays as the car has already warmed up. If I accelerate a bit then it starts to work. If I restart it this time it kicks in after a while. See log 1.
  2. Idle fluctuates at 1000 or above rpm. You can see at the second logs that TP is almost same but there is an RPM fluctuation. See log 2
  3. Saying so, when ac clutch/request is on there is additional fluctuation. I am not sure if its connected to 2nd item. See log 3.
  4. Idle drops to 500 RPM when engine fan kicks in. See log 4. 

1-idle_not_kicking_in.llg

2-fluctuation.llg

2-fluctuation2.llg

3-ac_fluctuation.llg

4-fanON.llg

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There are  couple of reasons your idle ignition control is not working as well as it could:

1. Your TPS needs calibrating as it is showing 5.3% during idle - TPS lockout is set at 2% in your IIC setup tab so you are not getting below the lockout.

2. Your idle MAP is around 43kPa. Lockout is set to 45kPa so if it is slightly above it is not able to catch it. You could raise that to 60kPa. Your TPS lockout and speed lockouts will stop it from becoming active at the wrong time.

3. Rpm lockout is set to 1200rpm. Your warm up target is 1300rpm so you need to be above that.

Have you reduced the idle target from 1000 to 900 at 80-90*c.? Your base map in the other thread had 1000rpm there but I noticed in the logs now the target is 900rpm. Those cams seemed to be idling pretty stable for the most part around 1000rpm.

In your Idle Speed Control tab there are setting there that control things like when the engine fans, power steering and AC come on. Use those settings to sort out your fans and AC.

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Another little issue there. Your warm up enrichment has 18-22% above 80*c. Engines will often be operating in that ECT range.

If you have a close look at log 3 at 89*c your avg Lambda at idle is .79, which is not far off WOT Lambda.

As soon as it hits 90*c the enrichment is 0% and Lambda jumps to .90 avg. Drops back to 89*c and richens up to .79 again.

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5 hours ago, Rob W said:

Another little issue there. Your warm up enrichment has 18-22% above 80*c. Engines will often be operating in that ECT range.

If you have a close look at log 3 at 89*c your avg Lambda at idle is .79, which is not far off WOT Lambda.

As soon as it hits 90*c the enrichment is 0% and Lambda jumps to .90 avg. Drops back to 89*c and richens up to .79 again.

Thanks for helpful comments. I will check these. For the moment:

I have already calibrated TP but its still around 4-5%  dont know why. I will try to put lock out above that.

I have reduced to 900 rpm since it’s not fluctuating at that level.

For idle up tables I have zeroed the ac stepper but still there is a small fluctuation. Maybe its related to other points you mentioned.

About your second post, do you mean that   The warm up enrichment should also be zero at 80 ect?

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For point regarding your Fan on idle, you can try increasing your engine fan step from what looks like 0.4% up to 0.6 or 0.8%. The real problem is that your PID control for your throttle is not sensitive enough and so your target TPS is moving by 0.4%, but you actual TPS angle is moving by roughly 0.2% and so its not enough. E-throttle works roughly to the idea that the further you are away from target, the more "effort" the ECU will make to change the TPS angle. if you are only 0.2% off, its basically going to just let it be a bit off unless you have it tuned to be pretty sensitive.  (screenshot from someone else's config so the values wont match yours)

image.png.a4ca5894a4595460e755188080d7539d.png

You describe the idle as "not responding" when it first starts up in point 1. This might be somewhat by design. In you first log you can see the idle status is "hold-startup" until about 8.5 seconds into the log. Before this time its running a hard-coded set of startup numbers. 

In your AC log it looks like your AC step up table is supplying ~1.8% TPS increase when your AC request is switched on. This is taking your idle (either RPM or MAP) ups too high and so while throttle idle control still looks to be active, ignition idle control has been disabled and so your ignition angle goes from ~16* to 36* as per you IGN 1 table. This combined with the nearly 7% of TPS your AC step up is giving you is making you idle at ~1600 RPM. try dropping the AC set up table values to maybe half what they currently are. Also check your ignition idle control numbers to see if they are being exceeded. See screenshot for the values you need to check. (again, not your actual config because you didnt post it)

image.png.d715a03687e44a88a783a746bf90c8e6.png

Have you run through the guide in the help file where it talks about disabling all idle control systems, tuning open loop on its own, then enabling the idle control systems just to keep it stable. Its not supposed to be able to cope with massively different engine parameters, just to smooth things out and keep it running nicely if something isnt quite the same as when you tuned it.

 

 

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10 hours ago, cj said:

For point regarding your Fan on idle, you can try increasing your engine fan step from what looks like 0.4% up to 0.6 or 0.8%. The real problem is that your PID control for your throttle is not sensitive enough and so your target TPS is moving by 0.4%, but you actual TPS angle is moving by roughly 0.2% and so its not enough. E-throttle works roughly to the idea that the further you are away from target, the more "effort" the ECU will make to change the TPS angle. if you are only 0.2% off, its basically going to just let it be a bit off unless you have it tuned to be pretty sensitive.  (screenshot from someone else's config so the values wont match yours)

image.png.a4ca5894a4595460e755188080d7539d.png

You describe the idle as "not responding" when it first starts up in point 1. This might be somewhat by design. In you first log you can see the idle status is "hold-startup" until about 8.5 seconds into the log. Before this time its running a hard-coded set of startup numbers. 

In your AC log it looks like your AC step up table is supplying ~1.8% TPS increase when your AC request is switched on. This is taking your idle (either RPM or MAP) ups too high and so while throttle idle control still looks to be active, ignition idle control has been disabled and so your ignition angle goes from ~16* to 36* as per you IGN 1 table. This combined with the nearly 7% of TPS your AC step up is giving you is making you idle at ~1600 RPM. try dropping the AC set up table values to maybe half what they currently are. Also check your ignition idle control numbers to see if they are being exceeded. See screenshot for the values you need to check. (again, not your actual config because you didnt post it)

image.png.d715a03687e44a88a783a746bf90c8e6.png

Have you run through the guide in the help file where it talks about disabling all idle control systems, tuning open loop on its own, then enabling the idle control systems just to keep it stable. Its not supposed to be able to cope with massively different engine parameters, just to smooth things out and keep it running nicely if something isnt quite the same as when you tuned it.

 

 

Thanks. I have walked things through. About your last comment, I tried to disable ISC by deleting base position table but idle dropped to 500 rpm or so and stalled. I could not find how I can increase this without ISC. Can it be done by adjusting idle ignition table?

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5 hours ago, namre said:

Thanks. I have walked things through. About your last comment, I tried to disable ISC by deleting base position table but idle dropped to 500 rpm or so and stalled. I could not find how I can increase this without ISC. Can it be done by adjusting idle ignition table?

I think what CJ means is that you turn the Idle Ignition Control off, AC step, Fan Step, Power Steer Step to zero and tune the idle as best you can using the Base Position Table, then enable the IIC and switch up your fan step etc as you need it.

In your main ignition table there is a block of 25* timing where it idles, but when the Idle Ignition Control is actually active it idles at target with around 15* in the IIC table. Once it gets above the 45kPa lockout it jumps out of the IIControl and into the 25* and higher timing blocks in the main ignition table so the idle rises and fluctuates.

Try and get to your idle targets using the base position table and the block of timing in the idle cells. Edit: You should be able to change that block of 25* where it idles to 15* as per what it is using from the IIC table. Then turn the IIC back on with whatever timing you have in the idle blocks in the centre or "0 Target" column with lower timing in the left or "-" columns and higher timing in the right hand side. Be aware that if you have the car warmed up when you do this you'll need to chase the base position up when it's cold also or it won't want to start.

Consider your fuelling as well while your doing all this.

I'm not familiar with Ethrottle but this is how I have done it with Sol/Stepper. You're not going to get the whole warm up thing right from the very start, it takes a few times to get it spot on. This is why it is not always perfect when it comes back from a tuning shop unless they have the car for a few days, so just take your time.

Read the help files like CJ said for Open Loop Idle and Idle Ignition Trim.

Edited by Rob W
better way

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OK. I have closed IIC and zeroed base position table and started from adjusting e-throttle target. It seems better now. I didnot start IIC again since this is where things get complicated and unstable. I guess this is not a problem?

Fluctuations happen over 1k rpm again. I believe this is also connected to my engine bucking problem at 2500 rpm. Deteriorating afr at this spot did not help. It might be mechanical due to lambda sensor or ethrottle or cams itself is all left maybe.

I have two widebands, one is lambda sensor just after the turbo and the other one is aem wideband sensor on some 30cms after the lambda. These two vary too much sometimes up to 2 points. And I've realized today that my lambda buzzes so much at the rpm fluctuation stage (at the bucking phase as well). This can be seen from the logs. It's too sensitive. When I check the other gauge it seems more stable. So which one to trust? Tuning was done according to lambda naturally. 

 

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update: after some research i decided to use idle ignition table at top. the issue was the older idle ignition table was correlated to ap% something and engine speed i guess. i reformatted it according to a 2d idle target error table as below. now it seems more stable. there are no dramatic drops in ac and engine fan. only handicap could be the rpm limit that needs to be 1400. so i need to start driving above that but that's the common way.  

image.png

image.png

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3 hours ago, namre said:

update: after some research i decided to use idle ignition table at top. the issue was the older idle ignition table was correlated to ap% something and engine speed i guess. i reformatted it according to a 2d idle target error table as below. now it seems more stable. there are no dramatic drops in ac and engine fan. only handicap could be the rpm limit that needs to be 1400. so i need to start driving above that but that's the common way.  

image.png

image.png

this is solved by turning tp/ap lock out to 1%. when I start to press the gas idle ignition closed automatically.

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