Light throttle tip in..
 

Just wondering if anyone has tuned out this problem.

Light throttle applications from idle cause small hesitation, where AFRs go lean. I am thinking of enabling the throttle pumps. Any other ideas?

TB mod? :)
How are you running around with no throttle pump? :eek:
:)


-Ted

I have this problem at off-idle

My throttle body is stripped down to the basic three throttles.

is this something I jus have to get used to, its not bad. And actually sounds kind of cool

You can tune that out to perfection, tune the throttle pumps and if it still persists try decreasing the throttle threshold value in the setup page.

on the throttle pump map, there are two bars

could somebody give me the jist of adjusting these, its not well explained in the haltech manual.

the other thing is that due to space limits, my throttle bracket is shorter than normal, and so my pedel movement is short and fast.

They MAY be enabled.. Maybe I just need to tweak a bit..

Yes, TB mod is done.

J-Rat, when you say you have small hesitation during "Light throttle applications from idle" is that just while your idling in nuetral and apply the thottle, or when you are taking off (not launching) in 1st gear? I have a slight hesitation when my (stock) clutch engages from a stand still and I have to give it a lot of gas to keep the engine from dying.

Enabling and tuning the throttle pump will fix this? I will research the function/use of the throttle pump, but I thought it was only for carbuerated engines.

When I am in neutral, and i give it a light throttle it stumbles a bit. But then again, it did this on the stock ecu too.

Make sure your timing progresses evenly. Too much of a timing jump will cause this.

its the tune, half the point of going with the standalone is to have instant throttle response, that stumbling is not normal with the haltech.

I would look at a combination of throttle pumps and the low vacuum bars right around idle rpm (high load bars) since the vacuum will drop dramatically right when you touch the throttle before the rpm increases, you may have to increase the fuel @ the far right around idle rpm and the next range up too.

Is the TPS mounted securely?
Sorry for the stupid question, but I had to ask... :)
If the TPS moves a tiny bit, it will cause weird problems like you describe.


-Ted

Just add a little bit of fuel with the throttle pump function. I already told you that would remedy it...just never got around to it when we were playing with the alcohol.

If you need me to I can come over and do it for ya I will.

To see if your TPS is moving (or not moving) Hook up your ECU to the laptop and bring up the engine data page.. then, whith the ignition on and the car off.. gently press on the pedal.. and see of the pedal moves at all before the throttle position value moves.. if it does.. could be that the tps needs some JB weld added to the inside and filed down to EXACTLY fit your shaft.

Turn the car on and then blip the throttle and see if there is any delay in raction of the map sensor or the TPS..

Where is your MAP hooked up to?? BDC and the Hitman tell me that the bottom front vac port on the plenum is the place to go as it has less variation and best response... I have mine hooked up there and have had no issues with the map sensor.. (i've had MANY other issues however!!!!)

Of course.. check for a Fault setting in the TPS


I have a fully modded t-body.. similar to what BDC does.. the second plates removed and all the excess metal removed between the thraots and sarpend into points.. If i take the throttle pump settings on the 0-1500 range down below 50.... it stumbles all over the place when you blip it at idle... after about an hour of annoying the neighbors last fall, i got it smooth as a baby's ass!!

Oh.. The TPS is NOT moving, trust me..

Thanks for all the tips guys!

Trev,

I was just trying to get some information regarding this problem. Yeah, if you want to come over this weekend and tweak some more, I am free all weekend. Also, we found out what the boost problem was.

Hesitation just off idle
 

i just chased this gremlin myself. this hesitation was most evident when just bliping the throttle on light takeoff i.e. from a light or in traffic.

About the TP settings:
There are 6 throttle pump bars. If i rememeber right 1,3,and 5 are the fuel % increase the ecu will deliver if the throttle pump is activated. 2,4 and 6 are the taper rates of how quickly this effect will diminish back to the base maps. <correct me if im wrong...

I found these to be helpful:

1) make sure the first of 6 (this is %inc for <1500rpm) throttle pump bar is adequate. i think mine is ~55%

2) like stated above, too much advance can aggravate the situation. mine is currently flat around 15deg adv or i might have even dropped it to 8deg adv from 1-2K rpm about 2-3bars on either side of 0psi.

*This helped the most*
3) richen up 2-3bars on either side of 0psi from 1-2K in the fuel base map. shoot for ~11:1 AFR. it is impossible to tell what afr you are running here unless you get rolling and put the car in high gear and floor it over this rpm range. remember to hold the throttle steady long enough for the TP effects to diminish to obtain your true AFR due to your base map.

Theory:
my guess is the TP is not activated unless the TPS is moved more that xx amount in xx seconds. most light blips to engage the clutch in traffic are below this "trip point" to activate the TP circuit. therefore you have to make your own effective TP by over riching these low rpm maps to compensate for MAP lag time.

justin

Thank you sir!

That brings up an interesting point...

Most of the proggies have TPS dead band parameters.
This should be run as low as possible - under 2%?


-Ted

I have my throttle pump dead band set at 1 and I still can't get it quite right from a stop light (moreso when shifting from 1-2). It will cut/miss for a split second then be normal again. I can see the lean spot on the WB and have tried adding a ton of TP but to no avail. I did have the throttle pump set to 3 and it was a lot worse but it's still not like a factory ECU. My TB is gutted like the others and I've also gone as far as making it a little progressive opening. The first 8% TPS movement is strictly the primary blade.