Anyone adjust for a quick start and quick transition to idle?

[WVULTRA]

Curious if anyone finalizes a tune by taking the time/effort to adjust for a quick start-up and quick transition to a nice idle?

Have read the Tuning Guide and it appears there would be 4 tables that could affect the outcome for an '08/earlier AFR Calibration:  Warmup Enrichment, Cranking Fuel, IAC Warmup Steps, and IAC Crank to Run.  Also appears the IAC Crank Steps in the Tuning Constants plays a role.  As noted in the Tuning Guide, the IAC Warmup Steps table is used along with some internal settings to establish the predicted position the IAC needs to maintain RPM at a given temperature.

It's also noted that:
 

It is not possible to directly correlate the IAC position with the IAC Warmup Steps table, as IAC position is the sum [/size]of several internal settings, variables, and learned offsets which are not accessible. The IAC Warmup Steps only contribute part of the actual IAC position reported by DataMaster[/i][/b][/size].

I'm wondering if that almost instant startup and quick to settle to the desired idle rpm is possible with larger/aftermarket throttle bodies, larger builds with non-SE cams, and custom headwork? Have noticed that even though the IAC Crank Steps in Constants has a value of 100, Data Master continuously shows ~130 steps prior to startup.  Also while recording nothing but idle rpm during a warmup, the IAC Warmup Steps are yielding 25-30 steps higher than the stock values in the map (DPC176).

Hear a lot of bikes that fire as soon as the start button is engaged, and quickly settle into a nice idle.  So, is this possible with custom builds?  And if so, anyone have a sure fire method on how to accomplish?

Many Thanks!

[rbabos]

This is an area that's driven me nuts. The only time I've gotten what I deem as normal is cold starts with slowly decaying to normal idle and an immediate hot start will return to normal idle. Anything in between, as in medium heat it will startup slightly fast, then slowly drop. I feel that is normal. Problem is once I start moving without a full heat up a slightly even faster idle will return and remain there until one of two things happen. I need to travel a short distance, as in a couple of blocks and stop. Then the idle will drop to normal and stay there the rest of the time. Second thing is to drive it long enough to fully heat the engine at which point the idle will be normal, even before coming to the first stop. Not sure if the tb size has much to do with it since I'm running a 46mm at the moment. I'm possitive it's some form of temp adjustment within TTS related to iac points but really haven't been able to ever get this area to my liking. I expect a slightly higher idle speed, much like during a cold start mid temp idle but the mid temp restarts are always higher than that for some reason.
Would be nice to know exactly how this all plays out and where to make adjustments.
Here's the kicker. The stock 96 cal behaved the exact same way with mid temp restarts and drive aways. Way back I suspected a faulty head temp sensor, but since tts and datamaster it seems to function normally.
Ron

[WVULTRA]

Would be nice to know exactly how this all plays out and where to make adjustments.

Seems very few actually know; or it may simply be too much trial an error to make it worthwhile.

Thanks for your reply!

[blusmbl]

The idle is elevated when moving to help with ridability and emissions.  I'm not sure exactly where the vs clip is, but it seems like something below 3mph and the idle returns to the base setpoint.

WVUltra- do the 08-earlier have an idle setpoint vs. coolant temp table like the TBW bikes do?

[WVULTRA]

The idle is elevated when moving to help with ridability and emissions.  I'm not sure exactly where the vs clip is, but it seems like something below 3mph and the idle returns to the base setpoint.

WVUltra- do the 08-earlier have an idle setpoint vs. coolant temp table like the TBW bikes do?

blu:

Not familiar with the tables you mention in '08 and earlier Touring maps; especially "coolant" temp.

[WVULTRA]

Ron:

Did some experimenting in the garage, and found out that reducing the IAC Crank Steps (in ECM Tuning Constants) from 100 to 85 reduced the before starting IAC Steps from 130 to 115.  Reduced the constants setting down to 70, and the IAC Steps pre startup showed 100.  So it appears there's a direct relationship between the Constants setting and where the ECM "parks" the IAC prior to starting.

Now the question is:  Will this produce any benefits?

[blusmbl]

The idle is elevated when moving to help with ridability and emissions.  I'm not sure exactly where the vs clip is, but it seems like something below 3mph and the idle returns to the base setpoint.

WVUltra- do the 08-earlier have an idle setpoint vs. coolant temp table like the TBW bikes do?

blu:

Not familiar with the tables you mention in '08 and earlier Touring maps; especially "coolant" temp.

Sorry, I'm used to water cooled motors- it's engine temp, not coolant temp.   I just checked a 2006 level cal, there is still the idle RPM table which uses engine temp as the normalizer.  Have you tried changing that table?

[Scotty]

I found when I had my 07 Fatboy and modified it that I had to get the IAC steps and TPS voltage spot on first then adjust the the following tables.
Warmup Enrichment
Cranking Fuel
Idle RPM
IAC Warmup Steps
IAC Crank to Run

The problem you get is that if you get the values to low the bike sputters to life and has to come up to the Idle RPM were as if you get them close to spot on the bike will start easy and go straight to a nice idle rather than flare up to 1500 RPM and then come back slowly.
Took a fair few starts from cold to get the tables set right but the biggest thing still was the IAC steps and TPS voltage being correct first.

[WVULTRA]

I found when I had my 07 Fatboy and modified it that I had to get the IAC steps and TPS voltage spot on first then adjust the the following tables.
Warmup Enrichment
Cranking Fuel
Idle RPM
IAC Warmup Steps
IAC Crank to Run

The problem you get is that if you get the values to low the bike sputters to life and has to come up to the Idle RPM were as if you get them close to spot on the bike will start easy and go straight to a nice idle rather than flare up to 1500 RPM and then come back slowly.
Took a fair few starts from cold to get the tables set right but the biggest thing still was the IAC steps and TPS voltage being correct first.

Scotty:

When getting the TPS voltage "spot on"; was that using the throttle stop screw via Data Master to yield 0.57v?  My HPI TB is yielding 0.63v consistantly prior to startup and during idle.

Also curious if you made any adjustments in the Tuning Constants IAC Steps setting to initiate getting the IAC Steps correct?

Thanks for any details!

[Scotty]

I found when I had my 07 Fatboy and modified it that I had to get the IAC steps and TPS voltage spot on first then adjust the the following tables.
Warmup Enrichment
Cranking Fuel
Idle RPM
IAC Warmup Steps
IAC Crank to Run

The problem you get is that if you get the values to low the bike sputters to life and has to come up to the Idle RPM were as if you get them close to spot on the bike will start easy and go straight to a nice idle rather than flare up to 1500 RPM and then come back slowly.
Took a fair few starts from cold to get the tables set right but the biggest thing still was the IAC steps and TPS voltage being correct first.

Scotty:

When getting the TPS voltage "spot on"; was that using the throttle stop screw via Data Master to yield 0.57v?  My HPI TB is yielding 0.63v consistantly prior to startup and during idle.

Also curious if you made any adjustments in the Tuning Constants IAC Steps setting to initiate getting the IAC Steps correct?

Thanks for any details!

This is my opinion and so might not be what other people accept but HD's 0.57v is on the outer limits and your setting needs to be lower and the IAC steps need to be set properly as well.
You might need to cut the tab of the TPS and elongate the holes so you can get some adjustment in it.
I like the voltage around 0.50 when the IAC steps are at 40 when the motor is at 100C
If you get those settings correct then the rest will sync in easier.

[WVULTRA]

Scotty:

Looked at an earlier Data Recording of an idle warm-up, and with the Desired Idle @ 1000rpm, IAC Steps in Constants @ 100 steps, and the other tables you mentioned above set to stock, my results @ 100*C were:

IAC Position:  36 steps
TPS Volts:      0.63v

Thinking now I'm needing to adjust the throttle stop screw and TPS as you mentioned.

[Scotty]

Just remember as you adjust one the other will change so it is a balancing act to get them set.

Took me about 5 tries the first one I did and about 3 now to get it right.

[WVULTRA]

After a lot of research and some great input from Scotty and Lonewolf, I finally got the TPS and IAC Steps set to the recommended level:



Started by removing the POS stock throttle stop screw which requires the T-15 Tamper Proof Torx bit; and I soon found out it was easily rounded off using a Snap-On bit.  Used isolated heat from a handheld propane torch and small vice grips to get it out the back side.  After tapping the hole for 1/4X28, I used a Grade 8 HH bolt 3/4" long.  After grinding ~.060" off the bolt head, and cutting the length back ~.065, it was a perfect fit when the bolt was screwed all the way in.  Shortening the bolt prevented any threads from protruding out the face of the throttle body.  If a 1/4x28 - 1/2" long bolt would have been available locally, then I could have skipped the shortening step.

Also removed the TPS, ground off the locating tab, and elongated the holes a bit to provide some adjustability.  After reinstalling the TPS, used Data Master to get an initial setting at Key On/Engine Off as close to .40v as possible. Put a good amount of blue loctite on the HH bolt, installed from the backside, and reinstalled the backing plate and air cleaner.  Started the bike and let it warm up to ~100*C and I could easily adjust the HH bolt to get the Steps in the 38-42 range.

IMO, this is well worth the effort and a must do on any engine other than a stock Stage1 setup.  Appears the MAP readings are good, and this mod should allow the Starting and Warmup Tables in MasterTune to be utilized for quick start up and good idle characteristics.

[pauly]

So.... How does it idle now? Hot, cold, in between?

Thanks
Pauly

[wurk_truk]

If it's not, this thread should go in the Sticky Section Mayor has set up.

[Hilly13]

If it's not, this thread should go in the Sticky Section Mayor has set up.

[rbabos]

Good info. I remember trying to drop my tps volts to .057 once after changing the sensor out and could not go below .063. Considered hogging the slots but left it as is. Might consider it now or when I get the new tb and 120 on the go.
Have two questions, however. If a tune is done at say .060 volts and the tps is dropped to .045 volts won't it effect the tune over the whole range?
Any down side to dropping below or above the recommended .057-.063 volt ranges on the tps and what it effects other than this idle conversation?
Ron

[WVULTRA]

So.... How does it idle now? Hot, cold, in between?

Thanks
Pauly

Pauly:  What I noticed right off the bat was the bike was quicker to settle into the desired idle.  Can't really tell the idle has changed other than it appears to be a bit more stable at all temps.

As I stated above, I think I've set a good base line for making any mods to the MasterTune Tables that affect startup and quickness to a stable idle as Scotty mentioned above.

[WVULTRA]

Good info. I remember trying to drop my tps volts to .057 once after changing the sensor out and could not go below .063. Considered hogging the slots but left it as is. Might consider it now or when I get the new tb and 120 on the go.
Have two questions, however. If a tune is done at say .060 volts and the tps is dropped to .045 volts won't it effect the tune over the whole range?
Any down side to dropping below or above the recommended .057-.063 volt ranges on the tps and what it effects other than this idle conversation?
Ron

Ron:
Mine was the same......held a steady .63 during a complete warmup from cold.

Not sure if it would affect the entire tune, but I was also concerned if it might change the tune of the idle areas.  So, I did a VTune of just the idle and close areas in the garage, and saw no change in VEs to speak of.  Couple of faint, pink cells from simply raising the throttle above the TP/RPM where it would be in normal cold/hot idle.  I did give WUE enough time to zero out.

As to any downside to lowering the voltage below the .57-.63v range, I have no idea.  But I did quite a bit of research here and on the other forums; and it seems this is a common practice with builders/tuners that take the time to do it.  Of course, I'm sure there's some holdover from earlier model years that used the bushings in the TPS holes that could be removed to allow adjustment vs having to elongate the holes as on my '07.  Of course, the TPS is not a real expensive part; and if I had screwed it up, would have simply replaced it.   

TT410 mentions:

Many vehicles operate properly with a TP voltage as low as .49 up to .61VDC and require no repositioning.

This is referring to repositioning the throttle stop screw.  However, I still feel that starting between .40 - .50v is favorable to anything with a modified build and/or throttle body.  Just a hunch I guess from my research and what others have stated.

[rbabos]

Like I said , good info and will keep it in mind for my next tune.
Ron

[wurk_truk]

I have found that the rare times that Scotty posts, it is usually right on the money, and my hat is off to you, WVULTRA for taking the time a research into something that IS important but gets completely overlooked.

I have a DBW, so this isn't really germane to me, except, I feel that once the 120 gets rolling, I AM going to spend whatever time it takes to get as equally as good as idle, etc as you have.

I have been feeling and stating that most folks bypass this area and go with base cal settings.  You did good!!!

[WVULTRA]

I have found that the rare times that Scotty posts, it is usually right on the money,

and my hat is off to you, WVULTRA for taking the time a research into something that IS important but gets completely overlooked.

I have a DBW, so this isn't really germane to me, except, I feel that once the 120 gets rolling, I AM going to spend whatever time it takes to get as equally as good as idle, etc as you have.

I have been feeling and stating that most folks bypass this area and go with base cal settings.  You did good!!!

truk:  I appreciate the kudos!   

I'm thinking most tuners don't have the time, or feel it's really necessary, to work on this small part of a tune; but IMO it's one of those areas that yields positive results when we're working with the several related MasterTune Tables that can be adjusted to produce a quick, stable, start-up and idle at different operating temps.  We have the IAC Warmup Steps, IAC Crank to Run, IAC Steps in the Tuning Constants along with Warmup Enrichment and Cranking Fuel. All adjustable Tables that I feel have some importance, or they wouldn't be a part of the process!

Now, if I can figure out the relationship of those appropriate Tables, I might have accomplished something.   

GOOD LUCK with the 120R.   

[wurk_truk]

Hey, the more you dick with this and learn, the more you should post on this subject.  I agree with you 100% on your thoughts on this area of tuning.  I surely would like to hear you findings, etc and try to learn from what you have done.

[rbabos]

Hey, the more you dick with this and learn, the more you should post on this subject.  I agree with you 100% on your thoughts on this area of tuning.

Wurk

Yeah, but don't venture too far out of the box. Some tuners are sensitive.
Ron

[WVULTRA]

Hey, the more you dick with this and learn, the more you should post on this subject.  I agree with you 100% on your thoughts on this area of tuning.  I surely would like to hear you findings, etc and try to learn from what you have done.

Will do!