Throttle vs Airflow table

FlashPro questions & answers specific to the 2006-2009 (US, UK, Asia) S2000
shind3
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Throttle vs Airflow table

Post by shind3 »

I have unchecked the box for this but I'm still seeing a lot of ignition retard for the 1st minute or so. This causes a sudden increase in engine speed when it finally does get disabled near the 1 minute mark.Attaching datalogs and map.

Please advise on how to fix. Thanks.
Shek 70mm TP, 32.fpcal
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datalog0000.fpdl
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Last edited by shind3 on Fri Jan 23, 2015 11:24 pm, edited 1 time in total.

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Hondata
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Re: Warmup Ignition Retard

Post by Hondata »

That is not warm up ignition retard, it is ignition controlled idle behavior. Something is out of balance between the idle speed and ECU idle control via the throttle. For the first half of the datalog the idle speed is higher that the ECU requested, and the ignition has mostly hit the ignition controlled idle lower limit. After the throttle blip the upper limit of ignition controlled idle is reached.
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shind3
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Re: Warmup Ignition Retard

Post by shind3 »

I'm not sure I followed what you wrote.

For the 1st half, the idle speed is 1350RPM while the map calls for 1200. Then at the ~1 minute mark, the idle speed suddenly jumps to 1900 without touching the throttle and then gradually gets reduced to the idle target of 1200.

So, what is causing that sudden increase in RPM? Looks like the only thing responsible is a sudden increase in timing. So what is causing the sudden increase in timing?

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Re: Warmup Ignition Retard

Post by Hondata »

Up until the 1 minute mark the ECU to trying to bring the idle speed down using ignition controlled idle. At that point I would guess that it has reset the idle routine because of the difference in idle speed and target idle for a period of time. 20 seconds later the idle comes down to target.
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shind3
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Re: Warmup Ignition Retard

Post by shind3 »

Yeah, I understand that ECUs will adjust ignition to stabilize idle. I guess you're saying the ECU has hit rock bottom trying to bring the idle speed down. Wonder why it doesn't throw a code for 'idle speed too high' after it realized it's unable to bring the idle speed down with just ignition.

And why doesn't the ECU just reduce the throttle plate? It sits at 6% during the high idle when it could just reduce it to 3% like it does later.

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Re: Warmup Ignition Retard

Post by Hondata »

I don't think the ECU even has an error code for the idle speed being out of spec. I believe the throttle control module does most of the work.
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shind3
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Re: Warmup Ignition Retard

Post by shind3 »

Hondata wrote:I don't think the ECU even has an error code for the idle speed being out of spec. I believe the throttle control module does most of the work.
When you say 'throttle control module' are you speaking of this thing in the engine bay?
Image


If so, I was under the impression that this was nothing more than a bulky APP sensor and simply transmitted the pedal position to the ECU which then directly controlled the throttle plate. But it sounds like you are saying, there is a 2 way street between this module and the ECU and this module tells the ECU what the pedal position is, the ECU runs calcs and requests a certain throttle angle, but then this module is the final authority on how much to actually rotate the throttle plate by? Is that correct?

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Re: Warmup Ignition Retard

Post by Hondata »

Honda choose to implement DBW in an odd fashion for the S2000 (and TSX). The photo is the the APP sensors, driven from the thottle pedal via a cable. The throttle control module is a box under the dash on the passenger side. It controls the throttle plate and communicates withe the ECU via a serial link.
For other cars with DBW the throttle control module function was incorporated into the ECU, and the throttle pedal had the APP sensors.
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shind3
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Re: Warmup Ignition Retard

Post by shind3 »

Thanks for clarifying.

Does this look like an indicator of my throttle plate being more open than it should be at rest?

With the ignition on, engine off, the reported TPlate % is 4% during its mechanical rest position. After I blip the throttle to actuate the TB, the minimum TPlate % seems to be 7% for a while before a period of no activity returns it back to 4%. How does a properly working TB system compare?
TB test.fpdl
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Re: Warmup Ignition Retard

Post by Hondata »

It is hard to say without doing a back to back on the same car at the same temperature.
What we can try is adding in the flow vs throttle angle table. With a large throttle body this relationship changes, so that could be why the idle throttle opening overshoots and then closes after 30 seconds.
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Re: Warmup Ignition Retard

Post by shind3 »

That would be perfect!

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Re: Warmup Ignition Retard

Post by Hondata »

Done for the next release, which will be very soon. The S2000 is missing many throttle tables compared to the civic - probably the function that the throttle control module performs.
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shind3
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Re: Warmup Ignition Retard

Post by shind3 »

Sweet, thanks! Yeah, I understand the Civic has the Throttle Control Module functions built into its ECU unlike the S2000.

shind3
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Re: Warmup Ignition Retard

Post by shind3 »

I see the update to v2.0.3. Cool.

Just to confirm, I should be increasing the 'expected airflow' at the various TPlate % for a larger TB right?
Should the 1st value at 0.5% remain at 0?
I wonder if an offset or percentage change should be performed. My guess is that differences are greater at lower plate angles so an offset change would be more appropriate? But if I do an offset change, how do I deal with the 1st value which probably has to be 0 and not totally change the shape of the curve?

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Re: Warmup Ignition Retard

Post by Hondata »

I'd use a percentage increase. The first value should stay at 0.
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