Yo,
I understand. My much better half was hospitalized for a week and I was mindless.
Right! When Starting:•The engine requires an unrestricted amount of air to start, so EEC opens the IAC 100%.
IDLE:•As soon as the engine RPM self sustains and begins to stabilize we now need air to Idle. Air is allowed in from in front of the closed throttle body, and bypasses the throttle body plate. The air is then released into the open intake track flowing directly to the cylinders. The whole idea behind this is simply a way for the computer to give air to the engine without needing a driver. The IAC is not opened like door half way, its either open or closed completely. The EEC sends many pulses per second to flutter the IAC open and closed. It flutters so fast that you should notice any RPM fluctuation with a functional IAC. This fluttering is called duty cycle, when it's calculated a percentage of on time. So when the IAC is off it is at 0%, when it is fully open it is at 100%, and any RPM in-between.
read more if needed at http://web.archive.org/web/20101201013829/http://fordfuelinjection.com/index.php?p=39
Cleaning Procedures as Shown in Idle Air Control (IAC) Sludge; Poor Idle TSB 91-25-07 for 85-92 Bronco & F Series & many others; "...Hard cold starts, hesitation and stalls on initial start-up or during idle or decel may be caused by sludge in the throttle body and/or idle by-pass valve. Sludge deposits or oil film on the throttle body bore and plate or the idle air by-pass valve may cause one or more of the following conditions. Hard Cold Start, Stall On Initial Start-Up, Stall During Idle, Stall During Decel, Rough Idle, Rolling Idle, Hesitation During Acceleration. A new idle air by-pass service kit (F2PZ-9F939-A) [miesk5 note, see * below] is now available for service use to correct sludge contamination concerns of the throttle bore and plate only. It eliminates the need to clean the majority of past model throttle body applications. Cleaning is not required on sludge tolerant throttle body designs released for 1991 and newer model years..." by Ford
* see how Nelbur trimmed his IAC gasket @
I understand. My much better half was hospitalized for a week and I was mindless.
Right! When Starting:•The engine requires an unrestricted amount of air to start, so EEC opens the IAC 100%.
IDLE:•As soon as the engine RPM self sustains and begins to stabilize we now need air to Idle. Air is allowed in from in front of the closed throttle body, and bypasses the throttle body plate. The air is then released into the open intake track flowing directly to the cylinders. The whole idea behind this is simply a way for the computer to give air to the engine without needing a driver. The IAC is not opened like door half way, its either open or closed completely. The EEC sends many pulses per second to flutter the IAC open and closed. It flutters so fast that you should notice any RPM fluctuation with a functional IAC. This fluttering is called duty cycle, when it's calculated a percentage of on time. So when the IAC is off it is at 0%, when it is fully open it is at 100%, and any RPM in-between.
read more if needed at http://web.archive.org/web/20101201013829/http://fordfuelinjection.com/index.php?p=39
Cleaning Procedures as Shown in Idle Air Control (IAC) Sludge; Poor Idle TSB 91-25-07 for 85-92 Bronco & F Series & many others; "...Hard cold starts, hesitation and stalls on initial start-up or during idle or decel may be caused by sludge in the throttle body and/or idle by-pass valve. Sludge deposits or oil film on the throttle body bore and plate or the idle air by-pass valve may cause one or more of the following conditions. Hard Cold Start, Stall On Initial Start-Up, Stall During Idle, Stall During Decel, Rough Idle, Rolling Idle, Hesitation During Acceleration. A new idle air by-pass service kit (F2PZ-9F939-A) [miesk5 note, see * below] is now available for service use to correct sludge contamination concerns of the throttle bore and plate only. It eliminates the need to clean the majority of past model throttle body applications. Cleaning is not required on sludge tolerant throttle body designs released for 1991 and newer model years..." by Ford
* see how Nelbur trimmed his IAC gasket @
