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Author Topic: Staling when clutch depressed  (Read 35478 times)
catbed
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« Reply #45 on: March 10, 2014, 11:23:47 PM »

I just reread the thread to kinda update myself and I saw you changed MLHFM for the MAF and that seems to be it. Try changing KFKHFM to what it is from the file of which uses the MAF you currently have installed as it's stock unit or maybe "all 1 it". I think this will help out. I switched from the 1.8tAWP MAF(stock) to a 1.8t BEA which is a 3inch MAF housing with the exact same sensor part number as the AWP sensor. At first I only switched out MLHFM and was getting wierd dips in rpm at idle/offidle but it never stalled like you explained but would stall a couple times during a cold start attempt.( I am in FL so my idea of a cold start is like 72F) Also AFR would fluctuate constantly, I saw this from watching my WB meter match front o2 sensor lambda all while the engine rpm would surge and dip at idle. Sometimes if I really got on it during a run, afr would stay at like 10 at idle after and never re-adapt until I shut it off and restarted it and sometimes I would have to reset adaption values, after a few minutes a good AFR would be adapted to. If I was cruising before resetting adaption values, AFR would go back to stoich. I changed KFKHFM to the stock map values from a 1.8t BEA AudiTT225q, I think a CHbox ECU. Like magic, it all went away. I'm running just over half the injector you are and k04-023 turbo though.

KFKHFM is currently all 1's, and my intake tract is vastly different from an A-box car. General consensus seems to be resetting KFKHFM and tuning it via STFTs.
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AARDQ
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« Reply #46 on: March 11, 2014, 09:18:07 AM »

Couple of things I would check (I've been working to understand these functions myself since I hate how long it takes revs to drop on the 1-2 shift and may try to reduce the time a bit.)

Have you been through BBSAWE/fuel cutoff?  Could be a place to start/continue.  From this thread:  http://nefariousmotorsports.com/forum/index.php?topic=1710.15 Reply 19/Setzi the IDC sets whether the injector fires or not after injector on-time is calculated.  So even though you are showing that there is no fuel cut off, there still could be shutoff going on for some reason.  As an easy check, maybe increase KFTVSA, delay fuel cutoff on gear change (detected by the clutch switch, b_KUPPL).

Maybe you have changed things up enough mechanically that the idle PID should be looked at.  The Alfa FR page 570 (LLRM) describes the PID and how to go about tuning it.  Easy enough to put back to stock if it doesn't fix the issue...

(As an aside, somewhere in this thread someone mentioned torque reserve in the context of opening the throttle.  Torque reserve alters timing, not throttle position.  Increasing reserve pulls timing compared to base so that higher torque (from increasing the timing) is immediately available to react to loads.  Much faster than opening the throttle.  On the one hand, lighter flywheel = less inertia to carry through a starting load (A/C engaging for example).  On the other, it's easier to accelerate the load with a lighter flywheel -- so maybe less torque reserve is needed, not more?)


« Last Edit: March 11, 2014, 07:48:15 PM by AARDQ » Logged
catbed
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« Reply #47 on: March 11, 2014, 09:34:10 AM »

Couple of things I would check (I've been working to understand these functions myself since I hate how long it takes revs to drop on the 1-2 shift and may try to reduce the time a bit.)

Have you been through BBSAWE/fuel cutoff?  Could be a place to start/continue.  From this thread:  http://nefariousmotorsports.com/forum/index.php?topic=1710.15 Reply 19/Setzi the IDC sets whether the injector fires or not after injector on-time is calculated.  So even though you are showing that there is no fuel cut off, there still could be shutoff going on for some reason.  As an easy check, maybe increase KFTVSA, delay fuel cutoff on gear change (detected by the clutch switch, B-KUPPL).

Maybe you have changed things up enough mechanically that the idle PID should be looked at.  The Alfa FR page 570 (LLRM) describes the PID and how to go about tuning it.  Easy enough to put back to stock if it doesn't fix the issue...

(As an aside, somewhere in this thread someone mentioned torque reserve in the context of opening the throttle.  Torque reserve alters timing, not throttle position.  Increasing reserve pulls timing compared to base so that higher torque (from increasing the timing) is immediately available to react to loads.  Much faster than opening the throttle.  On the one hand, lighter flywheel = less inertia to carry through a starting load (A/C engaging for example).  On the other, it's easier to accelerate the load with a lighter flywheel -- so maybe less torque reserve is needed, not more?)

Thanks, I'll look into those modules and see what I can find.

As for idle reserve, it was my understanding that increasing idle reserve retards timing and opens the throttle plate at the same time. But I could be wrong.
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userpike
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« Reply #48 on: March 11, 2014, 12:51:23 PM »



lighter flywheel = less inertia to carry through a starting load (A/C engaging for example).  On the other, it's easier to accelerate the load with a lighter flywheel -- so maybe less torque reserve is needed, not more?)

I was thinking it wouldn't be just the starting load but the constant load after the accessory has been engaged.  like while the A/C is running, alternator load, PS pump, etc, or while all of it is happening. So a spike and then constant load. The ECU, I'm thinking would be using up more of the available timing with the lighter flywheel compared to a stock unit installed, If there were no changes made to the software. Does that seem correct?

I haven't found a thread in here yet that really goes in depth about what to change in the software for light flywheels or switching from a dual mass to single mass.  I'm thinking idle fueling would be needing some refinement because it should take less fuel to keep the lighter flywheel turning right? or will it take more because the lack of inertia compared to the stock flywheel?

Who wants to start a light flywheel thread?





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prj
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« Reply #49 on: March 11, 2014, 02:12:01 PM »

1. More torque reserve is needed with lighter flywheels.
2. More proportional term is often needed as well.
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catbed
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« Reply #50 on: March 11, 2014, 04:24:09 PM »

1. More torque reserve is needed with lighter flywheels.
2. More proportional term is often needed as well.

Could this be causing my stalling issues? What is the general increase needed?

EDIT: I don't seem to have any of the idle PID components in my map pack, so I have been trying to locate them with a fully defined TT file. Not sure they are the correct locations. Don't mind the axes, I haven't looked into them yet.
« Last Edit: March 11, 2014, 10:30:46 PM by catbed » Logged
vdubnation
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« Reply #51 on: May 20, 2014, 08:59:58 AM »

any update on this
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catbed
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« Reply #52 on: May 20, 2014, 10:10:32 AM »

any update on this

pooched injector seals.  Roll Eyes barely ever stalls now, dips below idle often though.
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Parati
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« Reply #53 on: February 10, 2023, 07:32:44 AM »

Hello guys,

Very interesting thread. May I add:

My car have similar problems. It dips RPMs on upshifts, when you are engine braking @2000-4000RPM and suddenly clutches in, the engine almost stalls.

The catch, I run E100 and have wall wetting issues that I'm trying to fix via KFBAKL, KFVAKL and other settings (still did not try to chance injection timing).

I do believe this is a problem with the Air mixture with the fuel when the Throttle closes a bit.

Did you discover anything other than injector orings?
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