Causes of low compression, no start from a stuck closed IAC (part 2) - Toyota/Lexus

In this part 2 video we will focus on testing and cleaning the idle air control motor.
This was one of the weirdest causes of a no compression, no start problem that I have ever seen. Someone could have easily condemned the engine itself for this problem. Every other time I have heard an engine crank like this (no compression has a unique sound), it has always been a jumped or broken timing belt or chain. Going into this, I would have never thought a stuck closed idle air control motor could cause this condition. I've seen many sticking IAC motors in the past and with every single one of them, the engine would at least start up and run for a second or two.

Engine Performance Diagnostics chapter 20 pages 25-26

Symptoms
no start
start stall
will not idle unless the gas pedal is held open

Fix
clean stuck closed IAC valve

Tests shown
description and operation of the idle air control motor
how to test a 3 wire idle air control valve/solenoid
how to remove and clean an idle air control valve
wiring diagram review of a 3 wire IAC motor
how to measure a duty cycle controlled output
dangers of T pins

Tools used
digital multimeter
lab scope (Picoscope)
backprobing pins

Playlist
(Chapter 20) Idle Speed Problems and Testing
   • (Chapter 20) Idle Speed Problems and Testing  

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Chapter 20 "Idle Speed Controls" - preview (an SD Premium video)    • Chapter 20 "Idle Speed Controls" - preview...  
Ford idle air control valve (IAC) test - stalling problems
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For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
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