1st issue...the TP reading is at 3 at idle, when the gas pedal is completely let off. i have turned the TPS as far as it physically can and i cant get it anywhere lower. i was told that shouldnt not affect idle, but my idle right now is fairly high

2nd related issue, high and sparatic idle. at one point it was idling 2000-2500rpm, then i swapped back to a stock TB and it dropped slightly, apparently the TB plate on the bored TB doesnt seal well.

the symptons: when i first cranked the car, it idles so low that it would stall out unless i give it gas, sometimes it even stall out when i give it gas. ive played with the rpm fuel numbers but doesnt matter what i put, its still doing the same. after the car is warmed up for a few with me tapping the gas, it would idle nicely at about 750rpm -where i would eventually like it to stay. BUT, then upon further driving, it would start idling at about 1250 and eventually go up to 1500-1750. it is causing my car to overheat in traffic.

for background, i have a 2.5L V6 Probe GT, a mazda motor. im running the SDS 6E (w/ MSD ignition), with fast idle. only thing i can think of to do is to physically block off the factory IAC passage under the TB. i was suggested by a friend w/ SDS to adjust the MP numbers, but the shop who installed the system and baseline programmed it on a dyno told me not to change those values.

what is the problem? what should i do?

Thanks

no technical support on this?

you have the solution on your hands,block any factory iac and use the s.d.s fast idle control for warming up only ,you can also use the fast idle control to work with the a/c too.look at the tech section.tps is for richen the mixture for a short time when you hit the gas,is like an acelerator pump in a carb.

Just play with the knob and tune the fuel #'s until it gets to the point that when you turn the knob left(lean)or right(rich) the "sweet spot" is right in the middle,for example; if you turn the knob 30% to the right and it runs crappy,then turn it 30% to the left and it runs crappy,you are in the "sweet spot",if the percentage falls more one way,then add or subtract fuel at idle to get it "in the middle".If you purchase a wideband 02 sensor,then simply tune for 13-12 a/f ratio for a smooth idle,and advance at idle can sometimes help too.Don't forget to tune in "fuel cutoff" on deceleration. But that is another whole different subject,good luck.

Changing the MP #'s won't help. It's an air problem.
Need to block the IAC holes.
Then likely it has an idle speed screw to do fine adjust, if not you'll need to adjust the throttle stop screw.
Sounds like something is still controlling the air at idle, causing it to rev high. Look for solenoids/wires going to the throttle body, or hoses going to/from the throttle body area. Somethings opening and letting in more air when its warmed up.

Get our fast idle option to help it when cold.

usually they block the idle screw with a thin metal plate,but you will see something on the tb plate shaft hitting the end of a screw,look for a 3/8-1/2 " hole on the opposite side,stick a poky tool into it,and pry it out..you should be able to adj something..if i mistook the car,i might do some reserch,or give you some more info..

as far as the tp # goes,don't worry too much..I would actually put it up closer to 20..just make sure you don't 'top out' the tps(make sure the HIGHEST voltage(full throttle) it reads is ABOVE 3.5v,but BELOW 4.8 or so..)
this is where the sds begins to logg a/f ratio's..this could be usefull when you figure out some more stuff on the sds(not to condescend(sp??) but it sounds like you are on the upswing on your learning curve..)
it won't effect the idle at all,UNLESS you are using the idle tp setting..you just have to match the number to the number you get for a tp reading when you let go of it,you already know how to find this..then the fuel setting that makes it run well..maybe this is something you should try,it is easier at first,but you will still probably have to do some setting of your map settings..especially off-idle..it alsogives you a chance to play with the map value setting's 'curve';the idle tp number actually (I am pretty sure anyway)matches the map value you should put your map values at at idle..I will check this tomorrow..
now..IF you aren't using the idle tp setting,you have to see where your engine idles..(oh yeah..BLOCK OFF the factory idle solenoid..it is a pwn (frequency) based system,and it DOES let air through if it gets no signal..(I am assuming you have NO factory wires/computers still active in the engine )
I didn't get if you got the fast idle solenoid or not,it does make things easier..
and it does make some sense that the factory fast idle is heating up,and the spring is losing/gaining spring pressure,and it ends up opening when the motor heats up..
I would also check if you air box has some kind of pre-heat contraption in it that diverts hot air from around the exaust into the intake..I wouldn't defeat it,I would just make sure it is working..it helps alot in the winter..but it would be a cause for overheating..
ok,I re-read,you DO have fast idle,you have to make sure your fast idle shut off temp works(I would guess around 120-140)
ONCE you have blocked off the factory iac,then you should try to find out where your motor's map readings are at idle..(again,I would guess -22"+-)you should try to find your idle screw,it is nice to try to adjust that,but it shouldn't take much of a change,but again,it might..remember,if you change the idle screw,this changes your idle tp setting,and your idle map reading,and of course the rpm it idles at!!
when you find out where that is,(assuming the blocking off of the iac doesn';t tottally fix everything(doubt it,but maybe)..(just a side note,I took the bolt out of my fast idle solenoid,and attatched that to my 'evap' system(in 88 it wasn't an evap system per-se',but it puts the fuel tank under vacume,and I guess that should help to not have it under PRESSURE..DON'T mess around with something like this until all else is well,change ONE thing at a time..like change rpm settings,DRIVE IT,take notes,THEN change MAP settings,DRIVE IT,etc..EVENTUALLY you should get a better understanding of the system,and you can,but for now,the only things you should change at once is rpm between 500-1500,and you map values at idle..it may help(once you get it running right) to (for instance,perhaps the opposite..) RAISE the rpm #'s,to compensate,LOWER the MAP #'s(only ones at idle )..THIS IS NOT a 1 TO 1 RATIO,USUALLY it takes MORE map than rpm,they don't relate to the amount of fuel the same way(just take my word for it,if you do something to one,do the oposite to the other until it runs well again)
ok..when you find out where the map readings are,you SHOULD try to level off you map values at that point..
for instance..my car idles around 21,so to make it run right,I have my map values at 21.3,21.8,22.2,are all at 34(this will depend on you RPM fuel values as well,but from 500-1500 they should be about the same,both for starting,and idle...sometimes,you need to up the 500 a little,to let it richen on crank,but LITTLE BY LITTLE..IE:1 BY 1).
then ramp up the values 1 per map,until you fall into the pattern of +2 per map number..this again,is an other story,but you MAY need to change the rate of increase as the map increases,I had to put in a small section to ramp up 1 per map number from -16 to -13 ,then +2 per fromthere up..DON'T use this as any pattern for your motor,it's just an example..)
as I told someone on another post,you should invest in some graph paper,and put your map values on the bottom of the graph(one map VALUE per square,you don't have to do it -15,-14,-13 etc.. I would put it -16.1,-15.6,-15.2 etc.. then on the side,put your map SETTINGS,this you can do 1 per square,or 2 per,if your graph paper cant fit 120 squares toa side,either flip the page,or do the 2 per..now graph out your entire map,and look at it,it should be a smooth curve,at least right off idle ,then a line up from there..same with your fuel values..I have to ramp up my fuel alot,to prevent pinging,but my motor is 10.5/1 c/r,I don't think thats an issue I think your is around 9/1,so you should be able to get your timing up to 35-36 dbtdc.. I am pinging at 32 around 4500,again another story,but the graph thing works for all the maps,they shouldn't jump up/down/up etc..it shouldn't look like a stock report..
I just went throught the value setting procedure,but sometimes if you hear it from another person,it makes sense..anyway,post again,when you get the hang of this stuff,we can move on to the next thing..I wouldn't do much on the map values,but get your idle working with the above procedure(where the map readings are,even them out to let it run well,then +1 per map value,until you "hit" the pre-programmed setting patern)
and post again..(I said that didn't I?)
ttyl..Hope this helped..and didn't confuse you (post if I did this as well!!PLEASE I hate to confuse!!but I do too often..sorry..)
I know it is long,I have revised it 4 times now,ok 5now..,and it keeps getting longer..