Jump to content

Idle Speed Control -IgnAngle


Stu82
 Share

Recommended Posts

I'm probably just after confirmation, unless I do have an issue with my map..

I have installed, a set of JWT cams - notoriously lumpy idle (272/.385" 229@.050) in my Nissan 300zx '90. I can't get the car to run at all without idle speed control.

With ISC on, it's close to stock idle (RPM target 750, warm). Idle Ignition Angle is erratic.

My theory is ISC is battling Ignition Angle because of the lumpy cams, is this correct? And is this acceptable?

 

Thanks

PC Datalog - 2022-01-9 2;21;01 pm.llgx

Link to comment
Share on other sites

Idle ignition control is supposed to help with small idle speed deviations from target. Idle ignition control being erratic means it is doing its job - but its effectivity well depends on the settings you have (idle target/max clamp/min clamp) especially proportional gain and derivative gain.

Post your tune file.

Link to comment
Share on other sites

2 hours ago, essb00 said:

Idle ignition control is supposed to help with small idle speed deviations from target. Idle ignition control being erratic means it is doing its job - but its effectivity well depends on the settings you have (idle target/max clamp/min clamp) especially proportional gain and derivative gain.

Post your tune file.

I've currently got the Idle Ignition Control defaulted to 300zx map. I have played around with target, min and max clamp but didn't make any noticeable difference to how jumpy the control was.  Proportional and Derivative  gain, I don't completely understand yet.  

15jan2022.pclx

Link to comment
Share on other sites

Your idle ignition control settings look good.

It is just that after releasing the throttle, the idle dips before settling up again to target idle because of too low idle base position, too low ISC minimum clamp, and dashpot offset being zero. You would want to have the ISC min clamp and idle base position being close to the idle position % for the ECT value you have on the idle base position table. I suggest you do the open loop ISC tuning in the online manual, then whenever you have the values near what is required to keep idle target, then change it to closed loop.

Link to comment
Share on other sites

Thanks for having a look. I did follow the ISC procedure initially, but changed the idle base a bit since..maybe I'll  redo it. 

I never considered the dashpot. I didn't know what it was! I'll set it up tonight. Would you recommend add 10% offset and add a second to hold and decay? I'll also add in 10deg to min clamp.

Many thanks 

Link to comment
Share on other sites

Had a go with the dashpot settings, also carried out the open loop idle procedure again...added a bit more %.

It just doesn't seem to like anything regarding the dashpot. Coming down the revs it does some weird dip to hunting before it settles to idle. I did have a loop with MAP lockout and dashpot but raised the MAP lockout slightly. I'm also having a Lambda inconsistency which seems to be worse from cold and gradually gets better (but not still not balanced).  Playing with Cylinder Fuel Trims (+4% down Bank 2) seems to help, and then moreso when Lambda CCL kicks in. 

Log - https://drive.google.com/file/d/1W0QJUlckO1GHBhUzf0OqGzXqQiBFnkTG/view?usp=sharing

Hunt-to-Idle.JPG

Lambda-cold.JPG

15jan2022.pclx

Link to comment
Share on other sites

Dashpot offset would only be effective if the needed idle base position is more or less close to the currently needed idle position % to keep steady idle.

Like the ISC ignition control, the closed loop ISC could only correct small idle speed deviations from target, not to make drastic corrections.
You will be having to follow the open loop ISC tuning in the online manual, then whenever you have the parameters (idle base position, all offsets, min/max clamp, integral gain, etc.) near what is required to keep idle target, then change it to closed loop, then further fine tune.

Link to comment
Share on other sites

Yeah, confirming same as essb00.  Your log shows an idle position of 40-43% is required to achieve the correct idle RPM when warm, yet your base position table only has 28% in it.  

You need to get that base position table tuned before messing around with all the other comps.

HndgmIE.png

Link to comment
Share on other sites

On 1/24/2022 at 7:31 PM, Stu82 said:

I'm also having a Lambda inconsistency which seems to be worse from cold and gradually gets better (but not still not balanced).  Playing with Cylinder Fuel Trims (+4% down Bank 2) seems to help, and then moreso when Lambda CCL kicks in. 

 

BTW, the Lambda inconsistency you're referring to when cold is the warm up enrichment - that is normal (as that's what you have set), but you need to zero out warm up enrichment at 70°C as CLL would already activate and would cancel out the warm up enrichment.

Link to comment
Share on other sites

1 hour ago, essb00 said:

BTW, the Lambda inconsistency you're referring to when cold is the warm up enrichment - that is normal (as that's what you have set), but you need to zero out warm up enrichment at 70°C as CLL would already activate and would cancel out the warm up enrichment.

Regarding the lambda, are you sure? I would expect so, if it was a 4Cyl but its a v6 with 2 banks. I would expect to see both banks to be rich/lean. If I'm not understanding because I'm a noob, then why would the enrichment cause an inconsistency between banks? I've noticed since my previous post, I've plumbed in the Link boost solenoid wrong, potential for an air leak. I hope that's it.. SO much conflicting info out there for those solenoids...:unsure:

It was getting lean at 70c so added in warm up enrichment. Would it be better to turn up the CLL activation to 80c and leave the enrichment at 70c?

Thank you both for your support BTW @Adamw@essb00

Link to comment
Share on other sites

Try targeting a richer idle lambda when cold, where you see the big bulge in your lambda 2 it appears you have a misfire on that bank as the lambda becomes very noisy.  The misfire is probably due to it being too lean.  You can use the lambda target overlay table to remove say 0.1 lambda during warmup.  

Link to comment
Share on other sites

Instead of trim on bank 1, try to add fuel on bank 2 (negative value on individual cyl fuel trim table). It would also be good to check your ignition system especially bank 2.

Your CLL actually reacts too slow and very little corrections because of 0.00 in gain control table.

Link to comment
Share on other sites

Had an hour or so this afternoon. That lambda irregularity was 100% lack of fuel...

I enabled CLL at 0deg,to allow for Lambda Target Overlay
Added Lambda Target Overlay from -0.100 cold) to 0 (80c)
Added 1 Lambda gain across table
Added update rate at 1 across the table
Added more air at idle, where required
Added more warmup enrich.

The above has made a massive improvement. My lambda is flat right from startup. I did initially add too much warmup enrichment but CCL trim log is giving me a good idea where to tweak that now. Much happier with the cold to warm idle now. Dashpot works better too but still lumpy(because of 15c ignition angle and lumpy cams),I guess I can reduce hold and decay times to activate idle Ignition Control quicker.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...