raftdaddy

so the idle screw is completly useless and every tb comes with one that no ever should touch??, it fixed my car and the guy on the dyno stated that the position of the tb will choke off the intake causing bumping and surging when set to low,i'm not saying that is his problem but just trying to help. that is exactly what my car did and i had the dyno guy and the tuner on it after the fact. here is the guy http://www.wolfperformance.com/about.html he knows what he is doing.
i am not trying to be a sh*t cause i know very little but i'm just having fun being able to give adder a shot back, i have to take the rare oppertunity at hand!!

TrimDrip

Mine did that when I bought it. It gave an IAC code so I replaced it. It still did the same thing. Ran a wiggle test and found the ect was not getting a good connection. Put some contact grease on it and also found a vacuum leak off of the charcoal canister line and fixed it. The car hasn't done it since.

AdderMk2

you arent giving me a shot back, you are just plain ****ing wrong.

Opening the throttle plate wider to increase the flow of air at idle will skew the calculations that the ECM makes. This will cause issues with the IAC opening too far and raising your idle too much. The car will that try to compensate for it, and it will open the IAC less, which usually results in the idle dropping too low.

Then you get the surge.

At idle, the car will be pulling a specific airflow. That airflow is limited by the opening of the throttle plate. This value is programmed into the ECM. It's called Air - Throttle Body Air Flow (PID: ITHBMA). This value is the programmed base of the car idling at opertating temp, with no vac leaks, and the IAC completely shut.

If the throttle blade is opened past this value, it will affect the way the car runs. Especially in the first 20-45 seconds of the car being run, while the O2's are warming up, and the ECT's are rising... Initial start is a very ficle time for an EFI engine. There is alot more going on that you realize. Which is why you should always put things in proper spec, and not **** with **** you dont know about.

raftdaddy

that is exactly what i'm saying, if it is closed to far then the exact same theroy would apply only in reverse.there is a specific place that the blade has to be in.i'm not saying crank up your idle so it does not do it i'm saying make sure it is the right position!! i'm only saying this because after all my mods the tb blade was completly closed and the surge began.a slight turn of the screw and it stopped completley, then the tuner had it and said exactly what you said and it was closed to far. that is why they put the screw there.go ahead and argue with me but i had a guy with five nhra world records set the car up and he did not find anything but the tune wrong.

again i'm not saying this is his problem but it worked for me.and that is what i was told. so you say to put things in proper spec, how do you do that if touching it is the wrong thing to do?? and what if it is open to far right now??so are you saying that i never had an idle surge and that it did not or never could have fixed my problem??or everone is wrong unless you agree??? all i was trying to do was get you to possibly see that this is not the worst thing you can do ,it just one very simple thing that takes a second to do. you have helped me in the past i really did not want to burn my bridge with you but i am not questioning you just thought i would tell him my story and possibly help cause we all love our mustangs and not to be made out to be an idiot.

AdderMk2

if it was closed too far, the car wouldnt run.

as for how to put it in proper spec... i already told him to do a base idle reset. So, its covered... go sit down

raftdaddy

i'm done

TrimDrip

kinda what i was thinking

Bobert

Alright, back to some order. Now that Adder has shown his superior efi knowledge and raftdaddy is sitting down.

I have an update !!

Before reading what TrimDrip said, I did what he said. I re-ran codes and got a code 21. Put a spare Ect in that I had, and also fixed my charcol can feed line. I properly plummed it to the itake, before I just had it going to the throttle body vacuum input (where the stock crankcase vent hooks up to) on the air box side of the tb. I'm pretty sure that may have solved the egr/canister code.

Did all that, cleared the codes, set the idle, and its been running like a champ ever since. I didn't want to jump the gun and say this fixed it. But its at about 20 hot starts and 5 cold starts and no engine codes or extremely bad idle surges.

I am happy, but still a little nervous.

Fun side fact: in Canada a ECT costs $60 - $70 from a parts store. CanadianTire/Parts Source/APC. Autozone and LMR sell them for $20. Its just efffin bs. Ill be state side in a few days and probs pick up a ect just to have in hand. After searching for a while and reading the importance of that little bugger I want to have one handy!

Thanks again guys (y)