idles fine, drops, then slowly rises
#1
idles fine, drops, then slowly rises
I am am beyond confused with what I need to do to get my start up idle working correctly. I tried editing the ASE and WUE but neither seem to help. Here is what is happening, hopefully someone can point me to the settings i need to adjust.
The car starts and idles at 1100 rpms when its at around 86 degrees coolant temp (this is good). The car stays at this idle as the temps rise but once it hits 92 degrees it makes a noise and drops right down to 700, sometimes even stalling. If it doesnt stall the RPMs will slowly rise, very slowly, until it gets back up to 1100 rpms and everything is jolly again.
I data loaded this issue, it is pretty long but it shows the entire cycle. If someone can please take a look and point me in the right direction I would greatly appreciate it.
The car starts and idles at 1100 rpms when its at around 86 degrees coolant temp (this is good). The car stays at this idle as the temps rise but once it hits 92 degrees it makes a noise and drops right down to 700, sometimes even stalling. If it doesnt stall the RPMs will slowly rise, very slowly, until it gets back up to 1100 rpms and everything is jolly again.
I data loaded this issue, it is pretty long but it shows the entire cycle. If someone can please take a look and point me in the right direction I would greatly appreciate it.
#7
Thanks so much for getting me thtis far.
Also here are the setting i went with, are these safe? I kind of just guessed
#10
It seems you guys were a great help in fixing this problem! Sad thing is I am having another random idle issue I could really help with. The car starts up fine cold and drives fine up to operating temps. The issue I am having is if i drive in the heat for about 30+ minutes then let the car sit a bit, it fails to idle at start up. I turn the car on and it drops right down. If i rev the car the car to keep it from stalling and start moving the issue goes away in a few minutes.
Any idea where I should be looking or what I can post to help solve this issue?
Any idea where I should be looking or what I can post to help solve this issue?
#11
Boost Czar
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<p>look at your MAT Air Density table. youre removing TONS of fuel when the temps get warm.</p><p>My rule of thumb for that table is to set it completely to 100%. once your fuel table is good, then start adjusting that table to keep AFRs in check when the temps hit extremes.</p>
#12
If it's not running lean due to fuel air density compensation, you can also see if the engine needs more IACV duty. You can set your initial duty table to have manifold air temp on the y axis and make compensations there. I've had good luck adding duty with increasing air temp.
Unfortunately you can no longer compensate initial duty according to coolant temperature when you switch the table axis over.
To some extent you can tell how far off your MAT density table is by how much your closed loop fuel feedback is adjusting. If it's over 10% adjustment (for example, adding 10% fuel) then maybe it's too lean due to air compensation. That assumes the VE table was set pretty well when you initially tuned it though. A lot of these compensations can make you chase your tail if you don't get good baseline values in there.
Unfortunately you can no longer compensate initial duty according to coolant temperature when you switch the table axis over.
To some extent you can tell how far off your MAT density table is by how much your closed loop fuel feedback is adjusting. If it's over 10% adjustment (for example, adding 10% fuel) then maybe it's too lean due to air compensation. That assumes the VE table was set pretty well when you initially tuned it though. A lot of these compensations can make you chase your tail if you don't get good baseline values in there.
#13
Im in the car now and it seems that only helped a little. Now the car starts to idle but when i rev it and let it drop down the car stalls... Sorry for all the questions I just am at wits end here and need to solve this.
Attached are 2 data logs. One where I start it, rev it, and it dies. Another where i start it, rev it but dont let it die. In the 2nd log you can see the car struggle to idle until it finally stabalizes.
Attached are 2 data logs. One where I start it, rev it, and it dies. Another where i start it, rev it but dont let it die. In the 2nd log you can see the car struggle to idle until it finally stabalizes.
#18
I found these 2 threads but am not knowledgeable enough to know what my next steps are.
https://www.miataturbo.net/ecus-tuni...e-56061/page5/
https://www.miataturbo.net/ecus-tuni...hen-hot-67534/
Is this what you think my issue is?
https://www.miataturbo.net/ecus-tuni...e-56061/page5/
https://www.miataturbo.net/ecus-tuni...hen-hot-67534/
Is this what you think my issue is?
#20
Boost Czar
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Join Date: May 2005
Location: Chantilly, VA
Posts: 79,729
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<p>looking again, I think the DT is fine. 1.2ms is good for those injectors.</p><p> </p><p>what i see in the first log is the car running at 44% idle DC to maintain a smooth 950RPM idle.</p><p>when you blip the throttle and the car goes back to the initial duty table, it's aimin gfor 34%DC whihc is way to low for it to acheive a sustainable idle and it stalls. </p><p>I'd tune the intial idle duty table to values to that make sense.</p><p>I also see the idle valve nor spark react to try to hit idle, I dont like your delay settings and I would enable adaptive ignition timing so that MS uses spark angle to control idle when it gets too far off of targets.</p><p> </p><p>the scond log shows a VERY untuned idle valve. it's holding steady while your enginge speed ocssilates a good 250RPM.</p><p>I'd tune the idle control PID settings to values that allow the idle valve to WORK. Again, the delay is too long (10sec) and inital duty too low and why it's doing that initially in the log before it finally rises and stablizes.</p><p> </p><p>TUNE TUNE TUNE TUNE. you need to tune. tune the idle settings so the car idles well and doesnt stall. tune--as in tune the car.</p>