Throttle kicker

[CamaroDude85]

The $0D BJFD 4.3 manual bin I ended up using does not have Throttle Kicker checked but it does have parameters for Throttle Follower. One thing I found out that I haven't seen anyone mention when using a 7427 for a manual trans is having Acceleration Enrichment Limit and Closed Loop idle checked made a big difference. When I was trying to use the BHMC 305 auto bin I had problems with it going lean when pulling out and surging/bucking. I enabled both of those and it when't away completely when easing out on the clutch but would still do it pretty much as soon as the clutch was fully released unless you were above about 2300rpm. That's when I switched to BJFD and it all when't away and ran perfect.

[JeepsAndGuns]

Would be very interesting if there was a bit in the datastream showing when its turning it on and off. I'm curious to know when exactly it kicks it on and off, and by how much it opens the throttle.
So when you fire up your engine, I'm guessing it has a good flair up? My thoughts would be with engine off, no vac, TK opening the throttle a bit till engine fires and vac is produced and can pull it back?
I thought I remembered someone on here saying these pcm's take what the tps voltage is at key on and sets that as 0%? So if the TK is holding the throttle open a tad, then key is turned on, it sets that as 0%, then once it pulls back the tk, then wouldnt it be showing negative tps % numbers?

Mark, what idle and iac issues did you have? I remember on mine when I first started tuning the 7427, I would keep getting the throttle kicker failure code. I remember turning off the tk in the flags and it wouldnt pull out as good, so I turned it back on and simply turned off the error code. I would be curious to see if you did the same as I did at the start of this thread (mod a 0D 5.7 auto bin) and import the tk setting, if you would have the same results as me when you turn it on and off. Would also be curious if your idle quality and cold running performance/behavior changes for the better too.

Nasty-Z, how do you like that fuel pressure guage? Is it accurate? would you reccomend it? I have been thinking it would be cool and handy to have a electronic fuel pressure guage, but didnt even know anyone made one.

[JeepsAndGuns]

The $0D BJFD 4.3 manual bin I ended up using does not have Throttle Kicker checked but it does have parameters for Throttle Follower. One thing I found out that I haven't seen anyone mention when using a 7427 for a manual trans is having Acceleration Enrichment Limit and Closed Loop idle checked made a big difference. When I was trying to use the BHMC 305 auto bin I had problems with it going lean when pulling out and surging/bucking. I enabled both of those and it when't away completely when easing out on the clutch but would still do it pretty much as soon as the clutch was fully released unless you were above about 2300rpm. That's when I switched to BJFD and it all when't away and ran perfect.

You posted right as I started typing my last reply..lol

I do have closed loop idle enabled and also have that AE limit option enabled too. I remember reading through the comments on lots of the parameters and seeing that one, and thinking, yea, that would probably be good. I think I have had it enabled since the start.

[EagleMark]

I'm glad this throttle kicker is being discussed. Also glad I'm not the only one it's been Kicking in A$$!

Mark, what idle and iac issues did you have? I remember on mine when I first started tuning the 7427, I would keep getting the throttle kicker failure code.

Yup that was first... and then... and then...

It was my first conversion with this PCM. I had limited tuning with it at the time on trucks from factory with the PCM and no issues and I thought the problems were from running the $0D/$0E without a VSS? But I was determined to prove a statement that this PCM can not be run without VSS. OK I proved that wrong but swore I'd never do it again! Truck runs great! Fuel milage is close to double from carb and points, starts with a turn of key and never stalls cold or hot! Now with all this new info I don't think any of the issues I had were do to no VSS? It's the dam Throttle Kicker bin I started with...

I thought I remembered someone on here saying these pcm's take what the tps voltage is at key on and sets that as 0%? So if the TK is holding the throttle open a tad, then key is turned on, it sets that as 0%, then once it pulls back the tk, then wouldnt it be showing negative tps % numbers?

Very good point! If he is correct and what we are calling the Vacuum Operated Throttle Kicker is holding throttle blades open during Key On? Then the entire Algorythm (thanks RobertSaar!) has got to be differant? Vacuum creates very quickly so I don't think it would cause any flare... but if it is holding throttle blades open at Key on? This may very well be the point we have been searching for causing all the issues?

Nasty-Z Can you verify this again? Does that dam Throttle Kicker hold blades open at Key On?

The reason to start with a manual bin or auto bin is so many differences. Lots of IAC logic but also AE is always differant as well. From all the bins in all masks I remember it is more, which would make sense if you think of what engine is being told to do when shifting.

One thing I found out that I haven't seen anyone mention when using a 7427 for a manual trans is having Acceleration Enrichment Limit and Closed Loop idle checked made a big difference. When I was trying to use the BHMC 305 auto bin I had problems with it going lean when pulling out and surging/bucking. I enabled both of those and it when't away completely when easing out on the clutch but would still do it pretty much as soon as the clutch was fully released unless you were above about 2300rpm. That's when I switched to BJFD and it all when't away and ran perfect.

I always run Closed Loop Idle on stock and mild engines. Don't even like to start with bins that are not! Which are usually HD trucks... but the AE limit? Not sure what the limits are and not sure I would want to limit AE in a manual application... Not sure what BJFD application is? But may try it next time and do some testing of TK bins and known TK bins with Key On and hold throttle blades open and see where TPS% is set?

[Nasty-Z]

Nasty-Z, how do you like that fuel pressure guage? Is it accurate? would you reccomend it? I have been thinking it would be cool and handy to have a electronic fuel pressure guage, but didnt even know anyone made one.

I love it , probably within a pound or so of a good ashcroft mechanical gauge , I run one in most all of my EFI stuff , only problem is on some of the mild TBI stuff I do the sweep is not that good as it is at a lower pressure , the modded TBI stuff such as my '93 I have no problem @55 psi of fuel pressure :)

The one I use : http://www.summitracing.com/parts/ATM-4363/ That is the Pro comp Ultra lite , I have the Sport Comp version in a few of mine also , same gauge , different face.

Nasty-Z Can you verify this again? Does that dam Throttle Kicker hold blades open at Key On?

Yes it does Mark , then once the startup routine is complete the solenoid energizes and vaccum is applied to the actuator returning the throttle blades to the idle stop screw.

TOM

[CamaroDude85]

BJFD is for a 4.3 tbi manual trans truck. I'm not quite sure what it does software wise other than when I was trying to run BHMC it did keep it from leaning out when letting out the clutch. I think the problem I had with it still doing the surging/bucking was something to do with the spark advance though, that was before I built an ALDL cable so I was going blind with it at the time. Yep that's how I found it in the xdf's comment's it said something about manual trans = 1 so I figured WTH let's see what it'll do. There's quite a few things that I wonder what they do/how they work, makes me think how nice it'd be to be able to pick one of GM's engineer's brains that tuned these things lol.

[JeepsAndGuns]

but the AE limit? Not sure what the limits are and not sure I would want to limit AE in a manual application...

No, it doesnt limit AE, discription says it limits closed loop corrections while AE is active. I'm guessing that with it not checked, then it will make blm adjustments to the a/f ratio even when AE is active?

So are you still running without a vss?


Wow, that fuel pressure gauge is a little steeper than I thought. Still really nice and would like to have one. BUT, if I was to pay that much for one, I would want a 0-60 psi gauge. With me only running 45 psi, going all the way to 100 is pointless, plus 0-60 would have far better accuracy. Seems they dont make a electric one, all the 0-60 psi ones I saw were mechanical. Bummer.

[JeepsAndGuns]

Also still looking for a $0E hack. I tried google with no luck, every link I found was dead.
Anyone have a 0E hack?

[gregs78cam]

These are what I have been using, one is just the tables and scalars and the other is somewhat commented on the algorithm.....I think.

[JeepsAndGuns]

Humm, apparently my computer has no clue what those are, wont open them. Do I need a special program to open them?
The $8D hack I used when I worked on my 8D xdf was in PDF format, anyone have the $0E hack in pdf?

[EagleMark]

Notepad and choose all files.

[1project2many]

Humm, apparently my computer has no clue what those are, wont open them. Do I need a special program to open them?

They're just text files with a different extension. add .txt to the filename and Winnows will know what to do.

There's quite a few things that I wonder what they do/how they work, makes me think how nice it'd be to be able to pick one of GM's engineer's brains that tuned these things lol.

You might be amazed at how much information makes it to the FSM.

Idle Speed/Throttle Actuator - Mechanical: Description and Operation
Purpose: The idle speed control actuator system assists the idle air control system in controlling the idle speed, primarily at cold temperatures.
Operation: The idle speed control actuator is a vacuum operated device which opens the throttle slightly (2 to 3 degrees of angle) to increase the cold engine idle speed, to improve the mixing of the air and fuel, and to allow lower warmed up engine idle speeds. The idle speed control actuator is controlled by the idle speed control actuator solenoid, which is controlled by the control module. To increase the idle speed, the solenoid is turned "OFF," and no vacuum is routed to the idle speed control actuator, allowing it to open the throttle slightly. To decrease the idle speed, the solenoid is turned "ON" and vacuum is routed through the solenoid to the idle speed control actuator, allowing the throttle to fully close.
In conjunction with the idle speed control actuator system, the idle air control continuously monitors and controls the engine idle speed to the desired idle speed. A Tech 1 scan tool will read the control module commands to the idle speed control actuator system.

The throttle actuator provides another function. The larger the TB, the more the bores expand as the engine gets hot. The 92+ 454 equipped truck ran much hotter than the older square body version. And GM had switched to a heated intake instead of the small heater plate, which was much more effective at heating the TB and keeping it warm after the engine was shut off. Well, a larger bore means the throttle plate must be closed more to keep idle speed low. No problem, right? Just reduce minimum air by turning the throttle stop and you're done. But if you do that when the engine's hot, the next day when you go to press on the accelerator while the engine's cold, the throttle plate is stuck. Not so good. The throttle actuator allowed a way to reduce idle speed when hot yet keep the throttle far enough open when the engine was off so a cooling TB wouldn't seize the plate.

[JeepsAndGuns]

Selected notepad when my computer asked what to open it with and it worked! Thanks.
Well it appears all the TK parameters are in the xdf's. I used the find feature and only other things I found was what appeared to be a few TK datastream items.


1project, good info, thanks for posting. Very interesting.

[EagleMark]

1project, good info, thanks for posting. Very interesting.

X2

It's been awhile since I've had a FSM, man I would like to have quotes like that for everything!

Also intresting note 1project2many stated that the newer 92 454 runs hotter then old square body? Must be the newer body style did not have as much air flow through engine compartment... obvious assumption in looking at body styles. Thermastat temps would be the same. I know the old TBI water heated adapter was used in years before because GM used the same engine with TBI and Carbs on HD trucks. As HD trucks started using TBI then came the BB TBI intake.

Also intresting note that a Throttle Kicker is a ISA! Hard to find info on something that has wrong name...

[kevinvinv]

Maybe a quick resurrection of this thread?

I put a 454 into my 94 full size blazer. The TB that came on the donor engine (which I am using) does not seem to include this vacuum throttle kicker gizmo and I sure dont want to add it .

The bin I am using is a BHDH and I am getting a throttle kicker code thrown. Seems like I should just try to disable all throttle kicker features in the bin? What do you think... the early posts in this thread seem to indicate that this might not be a good idea though.

Any thoughts appreciated.