replace IAC
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Junior Member
Joined: Mar 2015
Posts: 21
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From: Virginia
Car: 1987 Formula
Engine: 5.0
Transmission: 5-speed
replace IAC
Guys, a couple of quick questions…
5.0L, 5-speed, '87, FB Formula; Dies when rolling up to a stop with clutch depressed. It doesn't want to idle. Replaced the MAF, fuel filter, engine coolant temp sensor and TPS.
Do I need to remove the plenum to replace the IAC?
I replaced the TPS and I could read the input voltage (5v) and the ground. I couldn't get a reading off of the center conductor on either the old TPS or the new one. Is there some trick to this? Maybe the connector is bad?
thanks, Jimmy
5.0L, 5-speed, '87, FB Formula; Dies when rolling up to a stop with clutch depressed. It doesn't want to idle. Replaced the MAF, fuel filter, engine coolant temp sensor and TPS.
Do I need to remove the plenum to replace the IAC?
I replaced the TPS and I could read the input voltage (5v) and the ground. I couldn't get a reading off of the center conductor on either the old TPS or the new one. Is there some trick to this? Maybe the connector is bad?
thanks, Jimmy
Re: replace IAC
Depending on your level of determination, it's possible to remove the IAC without removing the TB or plenum. It just threads in.
Before jumping to replacement, I'd pull the throttlebody, and remove the IAC, then clean the heck out of it. Spray carb cleaner and an old toothbrush, blow out all the IAC passages in the TB. Clean the bores really well. Scrub all the filth off the throttle blades front and back. Inspect the pointy end of the IAC pintle for grooves (shiny areas are normal, grooves are bad). Put it all back together and drive it a bit...
The throttlebody and IAC tend to get dirty just from the PCV system. High mileage and blow-by, leaky valve guides, etc lead to more oil vapor being circulated, and the tiny air passages that allow the car to idle get gummed up. Cleaning the system should be considered regular maintenance.
PS, when you go to remove the TB, there's a hard plastic vacuum line to the bottom. You'll want to carefully remove that vacuum line before man-handling the TB much. They're usually extremely brittle by now.
Before jumping to replacement, I'd pull the throttlebody, and remove the IAC, then clean the heck out of it. Spray carb cleaner and an old toothbrush, blow out all the IAC passages in the TB. Clean the bores really well. Scrub all the filth off the throttle blades front and back. Inspect the pointy end of the IAC pintle for grooves (shiny areas are normal, grooves are bad). Put it all back together and drive it a bit...
The throttlebody and IAC tend to get dirty just from the PCV system. High mileage and blow-by, leaky valve guides, etc lead to more oil vapor being circulated, and the tiny air passages that allow the car to idle get gummed up. Cleaning the system should be considered regular maintenance.
PS, when you go to remove the TB, there's a hard plastic vacuum line to the bottom. You'll want to carefully remove that vacuum line before man-handling the TB much. They're usually extremely brittle by now.