How to get more than 255 steps from IAC

For discussing injector selection,manifold modifications, throttle bodies, fuel supply system design and construction, and FIdle valves and IACs.
Forum rules
Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.

If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).

If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days

The full forum rules are here: Forum Rules, be sure to read them all regularly.
Post Reply
TheMonkey
Helpful Squirter
Posts: 109
Joined: Tue Mar 28, 2006 4:23 pm

How to get more than 255 steps from IAC

Post by TheMonkey »

i can put the number into MT as a higher number, but it does not move the pintle further out. i KNOW it has more range, because if i shrink 'Start Value' and fake out the start position, it keeps pushing it out.

is this in the INI file? i prob need 275-300 steps.

TIA,
Scott.
efahl
Site Admin
Posts: 102
Joined: Mon Feb 16, 2004 3:15 pm
Location: San Clemente, California, USA
Contact:

Post by efahl »

Scott,

Which value specifically are you looking at? The IACStart value has an upper bound of 4000 in the MS-II ini file that I have.

Eric
TheMonkey
Helpful Squirter
Posts: 109
Joined: Tue Mar 28, 2006 4:23 pm

Post by TheMonkey »

Eric-

i would like to be able to set the highest value in my IAC table to say... 300, and my start value to something just higher, like 310.

if i set my start value to 50, and my crank value to 200, and all my table values to 200.... then i can switch on, watch the pintle get sucked in 50 steps, and push out 200 (net 150 out). leave it there, turn off the switch again and on again, pintle retracts 50, pushes out 200 (net 150 out again). when out of TB, i can keep doing this, pushing out pintle prob 500 steps before it falls out. when installed in the TB, i need about 300 steps from retracted all the way to seated.

but.... if i set up my settings to be 300 crank, and 300 at all table values, and 310 on start value.... then, it should suck in 310 and seat (which it seems to do), then it should push out a full 300 steps and push against the seat. but it does not seat all the way. it only goes out 255 steps, and stops just shy of the seat.

from the manual: "The number of steps to go from fully open to closed is a user input, from 1 to 255 steps, although it can be made larger than that if needed"

this is not an INI file? i'm 99% certain i looked at this thoroughly, and just figured i needed to trigger something in the INI file.

thx, Scott.
efahl
Site Admin
Posts: 102
Joined: Mon Feb 16, 2004 3:15 pm
Location: San Clemente, California, USA
Contact:

Post by efahl »

TheMonkey wrote:this is not an INI file? i'm 99% certain i looked at this thoroughly, and just figured i needed to trigger something in the INI file.
Scott,

Yes, it's definitely in the ini file, I just wasn't sure what variable was involved. Look for this:

Code: Select all

      iacstepTable    = array ,  S16,    354,    [   10], "steps",    1.00000,   0.00000,  0.00,  500.00,      0 ; * ( 20 bytes)
In this version (2.871), the upper limit is 500 (second value from the end) so it would work for your purposes, but apparently it's lower in your version. This being an S16, signed-16-bit value, the max limits are -32768 and 32767, so you have lots of room to play.

Eric
Post Reply