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Old 11-07-2012, 11:08 AM   #16
stever975
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Quote:
Originally Posted by Louis View Post
Right, it isn't that.

No difference. ...
There are two tables in the calibration file directly related to the IAC operation. These are the "Idle RPM" and the "IAC Warmup Steps" tables. There are other tables that can be off that will affect the idle like the "Warmup Enrichment" and "Deceleration Enleanment" but these have a more subtle effect on idle control.

The Idle RPM table is a column of RPM values that are entered next to a fixed column of intake air temperatures. The IAC Warmup Steps table is used to help the ECM establish the target idle RPM quickly by providing an initial IAC step position for a given intake air temperature.

It's possible this later table is not set correctly but you haven't mentioned setting a P0505 DTC so I'm not sure your problem is related to the IAC not functioning properly.

The P0505 DTC will set if the idle is > 200 RPM from the target value for more than 5 s and the IAC pintle is fully closed or the idle is < 200 RPM from the target value for more than 5 s and the IAC pintle is fully open. The VSS must be zero and the and the TPS must be < 1% open for this DTC to set since the ECM will attempt to control idle is either of these sensors aren't "zeroed".

If you haven't set this DTC then the ECM is not having a problem with idle speed control and your stalling issue is likely due to some other problem like ignition or fuel delivery (e.g., a leaky injector).
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Old 11-07-2012, 11:17 AM   #17
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Quote:
Originally Posted by stever975 View Post
There are two tables in the calibration file directly related to the IAC operation. These are the "Idle RPM" and the "IAC Warmup Steps" tables. There are other tables that can be off that will affect the idle like the "Warmup Enrichment" and "Deceleration Enleanment" but these have a more subtle effect on idle control.

The Idle RPM table is a column of RPM values that are entered next to a fixed column of intake air temperatures. The IAC Warmup Steps table is used to help the ECM establish the target idle RPM quickly by providing an initial IAC step position for a given intake air temperature.

It's possible this later table is not set correctly but you haven't mentioned setting a P0505 DTC so I'm not sure your problem is related to the IAC not functioning properly.

The P0505 DTC will set if the idle is > 200 RPM from the target value for more than 5 s and the IAC pintle is fully closed or the idle is < 200 RPM from the target value for more than 5 s and the IAC pintle is fully open. The VSS must be zero and the and the TPS must be < 1% open for this DTC to set since the ECM will attempt to control idle is either of these sensors aren't "zeroed".

If you haven't set this DTC then the ECM is not having a problem with idle speed control and your stalling issue is likely due to some other problem like ignition or fuel delivery (e.g., a leaky injector).
Thank you. It isn't the warm up tables because it happens warm. It isn't the idle speed setting. It isn't the decel because it doesn't stop happening a few seconds after coming to a halt - although if I keep the engine going with gentle blips it does recover after thirty seconds or so.

I agree it could well be a leaky injector or electrical issue - not least because it started as an occasional issue and is now consistent, which suggests something failing.

I hope it isn't making the mapping work I am doing moot...
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Arnotts, D&D, SEPST, custom paint or all chrome according to mood, GRC seat, wave rotors, Muscle wheels, Burleigh bars, V-Gauge, assorted pretty bits.



2007 VRSC-AW (Fun).
2007 KTM 990 Adventure (Off Road and Touring).
2006 Triumph Daytona T955i (Evil).
2009 Fatboy (Heavily Tarted Up Show Pony).
2011 Bonneville (On long term loan).
1978 Triumph Bonneville Based Racer (Needs A Rebuild)
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Old 11-07-2012, 01:01 PM   #18
FatbyRR
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I have calibrated IAC for production so this is not a guess.
Most IAC motors WEAR OUT. They get sloppy and add or loose counts when running. As your problem happens both cold and warm It indeed could be calibration. First Idle position (TPS) must be within a range for proper IAC function. Anything done that changes TPS ZERO will effect IAC!
Secondly, those "warm up" stes are not intuitive on HOW they work! You are not "adding" any step in that TABLE. What that table does is modify the "IAC base learned position" vs. warm up steps.
A simply explaination is say at a given warm up temperature the "expected ERPM" is 1400. At "IDLE" the expected RPM is say 1100. The base learned IAC value at 1100 fully warm idle is ~15 counts.( for arguement sake) So if the IAC position at 1400 rpm vs. temp. and at that "warm up" point the IAC is at 26 counts, the "value in WARM UP counts" would be 11. If for instance you had only 5 counts in the warm up table at that point, the BASE LEARNED IAC posistion would go UP to 21 counts.
So if you rode down the road from a given temp/warm up table ERPM, when returning to IDLE the "fully learned Base IAC (Base IAC position is learned and changes slightly ever time). But in the above "senerio" your idle would hang high as the base IAC counts learn back to what is needed for 1100 rpm! However, IF you have too many "warm IAC" counts in THAT table, say 26 counts, where the actual counts are also 26, the base learned IAC counts would be moved to ZERO, so if you ride off and warm the temp. to normal, when you return to IDLE the "BASE LEARNED position" would need to LEARN UP form ZERO.

Warm up table values are SUBTRACTED from "current IAC" posistion vs Desired RPM(at a given temp)
Base learned IAC -warm up counts=current IAC base learn.

Those counts (warm up table) are there to help NOT change the "Normal" IAC base learn. So if your fully warmed up RPM needs 15 counts, you add the OFFSET (the number of counts for each increase in RPM vs TEMP) and then at whatever Desired RPM is when you ride off, and return to IDLE at FULLY warm desired IDLE the counts will be close and not droops or sags.
Many folks think they are "ADDING" counts in the warm up IAC table, but what that table does is a subtraction from "current warm up RPM vs temp." from BASE LEARNED position!!

So yes, that too can screw up fully warm IAC position if you had too many counts in the table and also IF that table is NOT ZERO at normal IAC fully warm desired speed!!

All that said, when you turn the key on/off/on/off,
all you are doing is resetting the IAC position!

The IAC does not have a sensor for POSITION! It ONLY "knows" where it is at key off/on reset. There is a table that drives the IAC into the seat then BACKS it OUT a calibratied amount of counts.
"Park Position" When you start up, the IAC motor assumes those "park position" counts as BASE position. As you ride down the road the IAC motor continually moves in and out vs. throttle! as well as desired RPM! As "slop" develops over time in the nylon threads of the IAC motor, the pintle can and does loose track of position as a function of counts.
So when you return to IDLE the actual pintle position can be very different than what the ECM thinks is IAC position..IAC motors are a large reason cars have gone to Drive by wire!
As you maybe can tell! I hate IAC motors as they caused me no end of trouble in my career!

It was always the calibration engineers fault when
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Old 11-07-2012, 01:21 PM   #19
stever975
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Quote:
Originally Posted by FatbyRR View Post
I have calibrated IAC for production so this is not a guess.
Most IAC motors WEAR OUT. ....
.....
.....
.....

It was always the calibration engineers fault when
A P0505 DTC would set if the IAC motor couldn't control the idle.
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Old 11-07-2012, 01:23 PM   #20
Louis
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Quote:
Originally Posted by FatbyRR View Post
I have calibrated IAC for production so this is not a guess.
Most IAC motors WEAR OUT. They get sloppy and add or loose counts when running. As your problem happens both cold and warm It indeed could be calibration. First Idle position (TPS) must be within a range for proper IAC function. Anything done that changes TPS ZERO will effect IAC!
Secondly, those "warm up" stes are not intuitive on HOW they work! You are not "adding" any step in that TABLE. What that table does is modify the "IAC base learned position" vs. warm up steps.
A simply explaination is say at a given warm up temperature the "expected ERPM" is 1400. At "IDLE" the expected RPM is say 1100. The base learned IAC value at 1100 fully warm idle is ~15 counts.( for arguement sake) So if the IAC position at 1400 rpm vs. temp. and at that "warm up" point the IAC is at 26 counts, the "value in WARM UP counts" would be 11. If for instance you had only 5 counts in the warm up table at that point, the BASE LEARNED IAC posistion would go UP to 21 counts.
So if you rode down the road from a given temp/warm up table ERPM, when returning to IDLE the "fully learned Base IAC (Base IAC position is learned and changes slightly ever time). But in the above "senerio" your idle would hang high as the base IAC counts learn back to what is needed for 1100 rpm! However, IF you have too many "warm IAC" counts in THAT table, say 26 counts, where the actual counts are also 26, the base learned IAC counts would be moved to ZERO, so if you ride off and warm the temp. to normal, when you return to IDLE the "BASE LEARNED position" would need to LEARN UP form ZERO.

Warm up table values are SUBTRACTED from "current IAC" posistion vs Desired RPM(at a given temp)
Base learned IAC -warm up counts=current IAC base learn.

Those counts (warm up table) are there to help NOT change the "Normal" IAC base learn. So if your fully warmed up RPM needs 15 counts, you add the OFFSET (the number of counts for each increase in RPM vs TEMP) and then at whatever Desired RPM is when you ride off, and return to IDLE at FULLY warm desired IDLE the counts will be close and not droops or sags.
Many folks think they are "ADDING" counts in the warm up IAC table, but what that table does is a subtraction from "current warm up RPM vs temp." from BASE LEARNED position!!

So yes, that too can screw up fully warm IAC position if you had too many counts in the table and also IF that table is NOT ZERO at normal IAC fully warm desired speed!!

All that said, when you turn the key on/off/on/off,
all you are doing is resetting the IAC position!

The IAC does not have a sensor for POSITION! It ONLY "knows" where it is at key off/on reset. There is a table that drives the IAC into the seat then BACKS it OUT a calibratied amount of counts.
"Park Position" When you start up, the IAC motor assumes those "park position" counts as BASE position. As you ride down the road the IAC motor continually moves in and out vs. throttle! as well as desired RPM! As "slop" develops over time in the nylon threads of the IAC motor, the pintle can and does loose track of position as a function of counts.
So when you return to IDLE the actual pintle position can be very different than what the ECM thinks is IAC position..IAC motors are a large reason cars have gone to Drive by wire!
As you maybe can tell! I hate IAC motors as they caused me no end of trouble in my career!

It was always the calibration engineers fault when
Hmm. OK, I think I'll copy every setting from the stock map. What you are describing could be it - some fool has set the map I based my own on to idle very fast when cold.

I have not made any changes that justify changing anything other than fuel tables from stock, so copy and paste time I think.
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http://www.flickr.com/photos/acam
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Arnotts, D&D, SEPST, custom paint or all chrome according to mood, GRC seat, wave rotors, Muscle wheels, Burleigh bars, V-Gauge, assorted pretty bits.



2007 VRSC-AW (Fun).
2007 KTM 990 Adventure (Off Road and Touring).
2006 Triumph Daytona T955i (Evil).
2009 Fatboy (Heavily Tarted Up Show Pony).
2011 Bonneville (On long term loan).
1978 Triumph Bonneville Based Racer (Needs A Rebuild)
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