Idle Issue?

[FExplorerL]

To get started I have a 1993 Ford Explorer Limited 4X4, has 294,000km on it. The problem I am having is if this truck idles for about a minute or longer I hear clicking noise coming from the engine bay. Now when this click happens my idle rises from what seems to be around 700 to about 1000 - 1200. I thought it might be the rad fan clutch clicking in but its been around -5 to 0 degree Celsius outside and hasn't been idling in one spot for too long nor should idle rise because of this.

Anyone have any idea what this could possibly be?

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[FExplorerL]

No one?

 

[BlakeOfDoom]

Have you listened to the idle with the hood up, outside looking at the engine bay? or is this from inside the cab? what kind of click does it sound like? electrical relay? metal on metal clicking? the fan slamming into something?

Only reason I ask was once I had to replace the heads on my truck and could not trace the source of a strange sound. After pulling the lower intake manifold ( for the second time after replacing the heads) I noticed nothing awry. I bolted everything back together, started it, and realized that the sound I heard was coming from a belt pulley.

 

[manaen]

does it have AC? if so it is your pump kicken in and out.. I know what your going to say.. I don't have AC on, well ford uses the AC pump to dry the air on all settings except the vent setting.

 

[FExplorerL]

@ BlakeofDoom the click is like when you tap your finger on your computer desk from inside the cabin. While looking under the hood its more of a click like a metal click not sure how to explain. By the way once it clicks idle goes up for 30 seconds then drop back to normal. After the initial click it doesn't happen for awhile.

@ manaen I'm guessing that when the click happens if I put my A/C on idle shouldn't change. If so I could take out the A/c fuse and disable this from happening?

Not a horrible issue, just I have to do an emission test and I don't think the technician will like this.

 

[manaen]

if it is the AC pump just put your heat/ac selector to off and the pump will not engadge anymore. no need to pull fuses.

you do need to address the idle surge as the IAC should be adjusting the rpm when the ac kicks on and off.

 

[2000StreetRod]

A/C idle speed

The PCM increases the idle speed when the A/C compressor is engaged to increase the cooling. If you monitor commanded idle speed with a scanner you can see it change.