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H/C Idle Question (already searched)

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Old Jun 7, 2005 | 09:10 PM
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Patriot StgII heads and 231/237 CAM in the car. I did do the home port job with the JB weld/tube and such in the TB if it matters

I want to make it idle so I turn the key and know it will run and not have to fool with the gas pedal to keep it alive with accessroies on. It idles as is with a little gas until it warms up and then you are good. Some occasional hot-start issues but nothing big.

I logged tonight and saw that my Desired IAT count went from 200 (when starting up) down to around 100 when it was idling by itslef. Timing is around 21 degrees on average from a cold start to operating temp. Airflow started at .83 oz/sec and ended up around .31 as well.

This is the correct PID to verify with ATAP correct "Desired IAT Count?" I will probably look at doing the screw as found in the stickied post but is there a way to adjust it easily through table adjustments?

Which throttle voltage to adjust? Normalized 0-100 I assume
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Old Jun 7, 2005 | 09:12 PM
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You have to get the iac count down by either drilling the blade hole bigger or adjusting the set screw, it's the only way to get them lower.
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Old Jun 7, 2005 | 09:45 PM
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I see.. I thought there may be a way to do it with LS1 Edit.

I hope to give this a shot tomorrow night and see how it works out.

Should you flip the screw around, set it back to the exact same voltage and do a reset before you start adjusting or can you just flip and set the voltage in one shot?
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Old Jun 8, 2005 | 12:33 AM
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You can flip it and reset it in one shot if you want. I have found that this is the major issue for car's not wanting to idle properly. Once you get this dialed in to around 30-60, things should be better. AFIK there isn't a table that will adjust the counts.
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Old Jun 8, 2005 | 03:47 AM
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Johnny, ironically we have nearly identical setups, to include year. If you go to Horist's .bin repository #8 is from me. I can hop in my car, turn the key and it fires right up. Now, I havent messed with the cold issue, or much on the cruise control effect but its a damn good start for you. Once at temp, idles great, and runs great, when its cold start, it will surge some and worse if you try to immediately take off before warm up. I have my TB Drilled, this was done pre-throttle blade adjustment info sharing. I can get the actual size tomorrow if you need it, but I believe its 1/4".
Basically I followed the old skool "cam tuning" by reducing VE in lower rpm, adding some timing also etc. My IATs are mid 40's.

Charlie
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Old Jun 8, 2005 | 08:03 AM
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I am sure you are looking at IAC (intake air count), not IAT (intake air temperature).

If the TPS reset and idle screw trick works for you, fine. I personally think that drilling the throttle blade is the easiest and most reliable method.

Till
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Old Jun 8, 2005 | 08:48 AM
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Originally Posted by Till
I am sure you are looking at IAC (intake air count), not IAT (intake air temperature).

If the TPS reset and idle screw trick works for you, fine. I personally think that drilling the throttle blade is the easiest and most reliable method.

Till
Which of these is IAC count? I would assume Idle AC airflow?
http://www.mustangmods.com/data/440/...8image0001.jpg
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Old Jun 8, 2005 | 09:10 AM
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IAC position
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Old Jun 8, 2005 | 09:22 AM
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I looked it up, and IAC is idle air control (not count). Idle Air Control Position is in PID GM.IAC. This is the number that indicates how much the idle air control opens up. Since the new cam needs more air to idle, this number goes up. You want to bring it back down to some number under 100. Some recommend something around 30 or 40.
To get the number down, you need to get extra air into the engine that doesn't go through the IAC system.
One way is the idle set screw, which keeps the throttle blade from closing. But then the PCM knows that it is open, and thinks something is wrong. Some had success with the TPS sensor reset trick, but that doesn't work on all cars.
Another way is to just drill a hole into the throttle body.

The next step is to get the air flow numbers right. Let the car cool down fully, start it and log airflow, IAT (intake air temperature) and ECT (engine coolant temperature). Take the logged airflow data, and put it into the two tables for "idle airflow" and "idle airlow parked" (some of this may differ in HP tuners). Let the car cool down again, and redo the whole thing in "D" to get the second column in your tables.

Till
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Old Jun 8, 2005 | 03:20 PM
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Did the first step tonight and flipped the screw around and put it to 2 degrees. Reset it and verified this all with atap.

I found that my counts were still high for just a while and I never had to put my foot on the gas. Right when I fired it up it took the rpm to 1000 instead of 850 or 900 that it is set to.

The odd thing was that the IAC did go from like 300 to 150 to 40 in less than one minute where before it would idle shitty for like 4-5 minutes and then settle down. Ohh and the airflow is now around .21 +/- also within that time frame. It started at 1.4 but came down quickly.

I'll have to do the stuff you mentioned Till because I don't know if it will still idle with the A/C on or not yet.

What do I do with the numbers once I get them logged?
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