Jump to content

Help please - Weird issues on rpm hang at 1400-1600 rpm after releasing pedal for some time before returning to idle


Jason Jason

Recommended Posts

Hi All,

i am a newbie and know nuts to ecu tuning and settings.  i got this tune from my previous tuner. However, there is an issue i really wanted to correct it so badly. i hope it could be some minor settings that could help me correct this behavior.

issue :

There is always this weird moment where the throttle will hang itself around 1.4k-1.6k rpm for awhile before coming down back to normal idling. its kinda annoying and normally it happen after i tap my accel pedal and release immediately.

 

Its an  engine , automatic transmission with fury ecu wired in. DBW throttle.

 

I have attached a log and the map. 

sincerely hope some experts here could guide me along please

 

thank you

 

Link to comment
Share on other sites

On 9/19/2020 at 4:42 PM, Adamw said:

Is the log of the car driving?  It appears to just be over-run that holds the RPM high.  Can you do a log of giving it a blip with the car in neutral/not moving. 

Hi Adam,

 

Thank you for replying,

Please find attached log. its just logged at different times. all on stationary.

On "light tap", im just merely giving a very very light tap to see the reactions.

On "Cold", it was throttled after car warmed up abit after 1st start of the day.

on "hot car delay", it was logged after driving the car around for 10-15 mins.

I realized upon light tapping the pedal , there is this weird reaction that theres no exhaust sound but the rpm will go up to 1.1k for awhile before dropping down to the idle again. suspecting it might the cause of this "hang" while driving as well.

 

Thank you so much for helping, appreciated.

 

Link to comment
Share on other sites

On 9/21/2020 at 2:23 PM, Adamw said:

I made many changes as it had some pretty odd settings in your tune.  Can you do a couple more logs using the tune below.  Since ive changed quite a bit it may still not be right so dont freak out if it is worse not better initially.  We should be closer after the next log.

Hi Adam,

Good day!

Appreciated. Thank you for the file.

i have tried to load in the map. It seems we are heading towards the correct way! 

 

Please find the reactions of the car as follow:

1. I have difficulty starting the car after loading in the settings initially, the car just couldnt fire up. it would just start and stall immediately. im not sure how i should compensate the firing up process.

so i tried to increase the idle base position to 1.5% and it could fire up. but it rumbles around 300-400 rpm for a moment before finally bringing up to a normal idle of 800-900rpm.

I have difficulty to start at ECT 50 temp too, at least require a 1.5% base position for it to rumble then to normal idle.

 

2. The idle seems much better now. its not as rough/aggressive as the previous tune. the compensation also seems to be coming on at correct time. Overall, idling are smoother than previous settings. (except the 300-400rpm rumbling/idling up crank start)

 

3. The Rev hang seems to be gone or the blipping seems very gentle now. not much random blipping during the drive (Great!). The Rev is dropping down smoothly when accel pedals are released. However, its seems to be dropping down very very very slowly with very little engine brake. the rpm will decline faster after applying brake, otherwise it could hold for awhile before declining the rpm by 100s in very long interval.

 

4. Thank you for giving me the new ethrottle target map, it feels closer to the stock throttle now. its doesnt feel "sputtering" now during the take off of the vehicle.

 

I tried to log the data at different moment during the drive, please advise if its adequate data for you.

 

Thank you again for helping, i believe we are heading near to the tune that was expected. the car operation feels much more "normal".

 

Link to comment
Share on other sites

Try this.  Your coolant temp sensor seems very odd during cold start. It sits at exactly 28deg for the first two minutes without moving, then suddenly ramps up to 70deg in about 1 minute?  Im not sure if you are going to get repeatable cold start with that but see how it goes.  

For the next log, with it idling warm, can you turn AC on/off a couple of times, ad move gear lever from P to D and back a couple of times.  

If starting is still an issue, try putting some numbers in the start up step table, rather than messing with the base position.

Linkecu-AdamIdleTweak-1-Map V2.pclr

Link to comment
Share on other sites

1 hour ago, Adamw said:

Try this.  Your coolant temp sensor seems very odd during cold start. It sits at exactly 28deg for the first two minutes without moving, then suddenly ramps up to 70deg in about 1 minute?  Im not sure if you are going to get repeatable cold start with that but see how it goes.  

For the next log, with it idling warm, can you turn AC on/off a couple of times, ad move gear lever from P to D and back a couple of times.  

If starting is still an issue, try putting some numbers in the start up step table, rather than messing with the base position.

Linkecu-AdamIdleTweak-1-Map V2.pclr 161.41 kB · 0 downloads

Alrighty. I'll try and share the reactions. Thank you again.

 

I think the reason of ECT bump up in 1 min because an external ECT sensor were used for links ecu to read. So there is a delay until water heats up to pass through the sensor. 

Link to comment
Share on other sites

On 9/23/2020 at 6:18 PM, Adamw said:

Try this.  Your coolant temp sensor seems very odd during cold start. It sits at exactly 28deg for the first two minutes without moving, then suddenly ramps up to 70deg in about 1 minute?  Im not sure if you are going to get repeatable cold start with that but see how it goes.  

For the next log, with it idling warm, can you turn AC on/off a couple of times, ad move gear lever from P to D and back a couple of times.  

If starting is still an issue, try putting some numbers in the start up step table, rather than messing with the base position.

Linkecu-AdamIdleTweak-1-Map V2.pclr 161.41 kB · 2 downloads

Hi Adam,

Good Day,

Please find the attached logs. felt better now and more stable.

rpm may drop lower but seems compensating coming in time. ( Thank you again! :) )

 

1. Crank start - i added 2.2 to get a smooth cranking to start up step. 

 

2. Rpm after release of accel pedal -

The RPM is reducing now much better compared to the previous.

but the weird part was the vehicle speed doesnt reduce but the RPM drops ( haha :) ).

 

im not sure if its any related to running an Auto Transmission. The previous tuner did some wiring up to duplicate the throttle position and feed it the stock ECU to read the throttle position so the AT gearbox would not limp and could shift according to stock TCM/ECU settings.

 

3. Dragging gears - The throttle position could be cause.

I think i know how it works now. but i dont think its the Links ECU issues.

Im guessing the stock ECU/TCM is relying on the throttle body position to determine its shift. So if too high of a throttle position will result in delaying shift or no shift. i may have to play around it or search for a base reference from an Automatic Transmission owner with DBW throttle control.

Would you by any chance have archived a base set of throttle position target map from an owner of toyota automatic(non-CVT) car that you could share for reference? (otherwise i would search the whole forum inside out haha :) )

 

Link to comment
Share on other sites

Ok, I notice your E-throttle PID is set up very soft too, the throttle is not following the target well after a quick pedal movement.  I dont really like tuning E-throttle without being there in person, but I have just made a conservative change in this attached file to see if it helps.  Can you load this file and do a log of some throttle pedal movement (engine doesnot need to be running), do some fast movements and some slow movements.  

Dont drive the car with this file, just use it to make the log then load your old file back in until I check the log and confirm it is controlling well.  

23.09_Linkecu-AdamIdleTweak-1-MapV3.pclr

Link to comment
Share on other sites

1 hour ago, Adamw said:

Ok, I notice your E-throttle PID is set up very soft too, the throttle is not following the target well after a quick pedal movement.  I dont really like tuning E-throttle without being there in person, but I have just made a conservative change in this attached file to see if it helps.  Can you load this file and do a log of some throttle pedal movement (engine doesnot need to be running), do some fast movements and some slow movements.  

Dont drive the car with this file, just use it to make the log then load your old file back in until I check the log and confirm it is controlling well.  

23.09_Linkecu-AdamIdleTweak-1-MapV3.pclr 161.45 kB · 0 downloads

Hi Adam,

 

Good Day.

Thank you again for the time & support. :) . ( not very sure what to say except thanks!)

Please find the log for this V3 map, im hope its usable. not sure if the fast ones at the back were too short of an interval between each other?

Adam file 3 - thorttle slow and fast log.llg

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.

×
×
  • Create New...