# Weird ticking noise and idle speed changes **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** bronco, ford\ **Created:** [July 24, 2016, 3:11pm UTC](https://community.cartalk.com/t/weird-ticking-noise-and-idle-speed-changes/94012 "2016-07-24T15:11:56Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![thebigmakowski](https://avatars.discourse-cdn.com/v4/letter/t/b77776/32.png) [@thebigmakowski](https://community.cartalk.com/u/thebigmakowski)\ **Post date:** [July 24, 2016, 3:11pm UTC](https://community.cartalk.com/t/weird-ticking-noise-and-idle-speed-changes/94012/1 "2016-07-24T15:11:57Z")
my 1993 5.0 liter bronco is making a strange ticking noise. when it’s idling, and it ticks, the idle drops. then it will tick again and the idle will raise up. usually between the 600 to 1000 rpm range. it just started doing this and never did before ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [July 24, 2016, 3:19pm UTC](https://community.cartalk.com/t/weird-ticking-noise-and-idle-speed-changes/94012/2 "2016-07-24T15:19:12Z")
Be specific re the conditions under which you hear this occur. ---
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [July 24, 2016, 3:22pm UTC](https://community.cartalk.com/t/weird-ticking-noise-and-idle-speed-changes/94012/3 "2016-07-24T15:22:57Z")
Is the ac on? if so does it do it with the ac off? ---
**Author:** ![thebigmakowski](https://avatars.discourse-cdn.com/v4/letter/t/b77776/32.png) [@thebigmakowski](https://community.cartalk.com/u/thebigmakowski)\ **Post date:** [July 24, 2016, 3:50pm UTC](https://community.cartalk.com/t/weird-ticking-noise-and-idle-speed-changes/94012/4 "2016-07-24T15:50:05Z")
no, a/c is not on. when it’s in park, it does the most extreme idle changes from about 600 to 1000 or so. when in drive it get considerably less but i can still hear the ticking sound every couple minutes cause a distinct change in rpms ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [July 24, 2016, 5:24pm UTC](https://community.cartalk.com/t/weird-ticking-noise-and-idle-speed-changes/94012/6 "2016-07-24T17:24:07Z")
The idle air control valve doesn’t make any noise that can be heard from the cab with the engine running. That valve opens incrementally, stepping upwards of 60 times from dead idle to 1,500 rpms as I recall and the only clicking that would be coincidental to the idle speed suddenly increasing is the AC compressor being cycled on by a relay but you say the AC is off when the rpms jump. Where does the sound seem to come from? Possibly you can open the hood and listen to isolate the click. ---
**Author:** ![kurtwm1](https://avatars.discourse-cdn.com/v4/letter/k/13edae/32.png) [@kurtwm1](https://community.cartalk.com/u/kurtwm1)\ **Post date:** [July 24, 2016, 5:41pm UTC](https://community.cartalk.com/t/weird-ticking-noise-and-idle-speed-changes/94012/7 "2016-07-24T17:41:20Z")
it probably ticks at higher rpm as well, you just don’t hear it because of the engine noise. You check your oil? ---
**Author:** ![thebigmakowski](https://avatars.discourse-cdn.com/v4/letter/t/b77776/32.png) [@thebigmakowski](https://community.cartalk.com/u/thebigmakowski)\ **Post date:** [July 24, 2016, 6:55pm UTC](https://community.cartalk.com/t/weird-ticking-noise-and-idle-speed-changes/94012/8 "2016-07-24T18:55:38Z")
thanks everybody, i figured it out. the guy i lent my truck out to broke the knob for the a/c when he tried to turn it on, not realizing it has not been charged. he stuck the knob back and i didnt even notice. i guess the clicking i was hearing was the compressor trying to kick on. never loaning my truck out again ---
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [July 24, 2016, 6:59pm UTC](https://community.cartalk.com/t/weird-ticking-noise-and-idle-speed-changes/94012/9 "2016-07-24T18:59:13Z")
I think the clicking was the relay for the compressor, and the engine had learned to adjust to the draw of the compressor on the system, but did not know the ac was not kicking in. Glad it was a cost free experience. ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [July 24, 2016, 11:06pm UTC](https://community.cartalk.com/t/weird-ticking-noise-and-idle-speed-changes/94012/10 "2016-07-24T23:06:07Z")
That guy you mentioned sounds kind of inconsiderate A decent person would have said “Thanks for loaning me the truck. I broke your AC knob off. I’m sorry about that, and I’ll get it fixed.” 👽