Pulsing Idle Disappears when Idle Air Control Valve is Disconnected

2knob · 04-19-2008, 11:54 AM

Thanks Chuck, you should be a motivational speaker. You motivated me to send for your tuning notes.

Throttle Adjusting Screw = TAS... Just goes to show that you learn something new every day, even when you don't want to...

I reinstalled the stock computer on the cold engine. When I started it, it raced to about 3000 RPM, but settled to 1500 RPM after a quick blip of the throttle. After it warmed up, it's idling at 1100 RPM (no pulsing), with the TAS fully backed out.

Does this mean there is a small leak around the throttle plates, or will it pull that much air through the Air Adjusting Screw?

cewrx7r1 · 04-19-2008, 02:02 PM

S1: I reinstalled the stock computer on the cold engine. When I started it, it raced to about 3000 RPM, but settled to 1500 RPM after a quick blip of the throttle.
A1: Sounds like you still have the AWS solenoid installed and hooked up. That is whay causes the short duration 3000rpm. It was to quicly heat up the pre-cat. Usless and bad for the engine.

S2: After it warmed up, it's idling at 1100 RPM (no pulsing), with the TAS fully backed out.
A2: Could be, but have you insured that the throttle is full closed? Improperly
adjusted throttle cable or cruise control cable may keep it from closing.
Stuck dashpot may keep it from closing. Bad hot wax rod/fast idle cam assembly may keep it from closing.

YOU HAVE to know the engine systems.
That is why I tell everyone, make section "F" of the Mazda manual your bible./

04-19-2008, 11:54 AM	#1
2knob The Newbie Join Date: Feb 2008 Location: Bay Area, CA Posts: 18 Rep Power: 0	Thanks Chuck, you should be a motivational speaker. You motivated me to send for your tuning notes. Throttle Adjusting Screw = TAS... Just goes to show that you learn something new every day, even when you don't want to... I reinstalled the stock computer on the cold engine. When I started it, it raced to about 3000 RPM, but settled to 1500 RPM after a quick blip of the throttle. After it warmed up, it's idling at 1100 RPM (no pulsing), with the TAS fully backed out. Does this mean there is a small leak around the throttle plates, or will it pull that much air through the Air Adjusting Screw?

04-19-2008, 02:02 PM	#2
cewrx7r1 The Judge Join Date: Feb 2008 Posts: 196 Rep Power: 18	S1: I reinstalled the stock computer on the cold engine. When I started it, it raced to about 3000 RPM, but settled to 1500 RPM after a quick blip of the throttle. A1: Sounds like you still have the AWS solenoid installed and hooked up. That is whay causes the short duration 3000rpm. It was to quicly heat up the pre-cat. Usless and bad for the engine. S2: After it warmed up, it's idling at 1100 RPM (no pulsing), with the TAS fully backed out. A2: Could be, but have you insured that the throttle is full closed? Improperly adjusted throttle cable or cruise control cable may keep it from closing. Stuck dashpot may keep it from closing. Bad hot wax rod/fast idle cam assembly may keep it from closing. YOU HAVE to know the engine systems. That is why I tell everyone, make section "F" of the Mazda manual your bible./