So I'm going over my truck, getting ready to haul my stuff up and down the mountains to Texas.

I put new injectors in a little bit back, that definitely helped with the power.

But I noticed the other day, that at idle with the hood open, I can hear a weird clicking noise every now and then, and the engine changes sound just a tiny bit. Not rougher idle or anything, just...different. Then after 30 seconds or a little more, back to normal.

What could this be ?

I have my KSB wired up to an on-off switch on the dash, so it's not that...I don't think anyway.

TIA !

 

Maybe the fan or altinater turning on and off.

 

A/C or defogger on?

Was this right after a cold start?

 

No, does it all the time. OK, maybe it's the alternator and completely normal ?

Defogger on, AC off.

It's still warm from driving earlier today, I'll go check it right now. Air temp in the upper 50s.

 

OK, I think it's the defogger. Normal then ?

 

Yhea, with defrost the a/c would be cycling on and off.

 

But it's cool out, and the lever is slid all the way over to the "red" side for heat. I don't understand why the A/C would go on and off...

 

Most vehicles are wired to run the A/C compressor when any defrost position is selected, regardless of set temperature. The reason is that air conditioning dries the air, as well as cooling it. The defroster is much more effective this way.

 

The reason it cycles is that the cycling switch is seeing low temperature in the suction line and shutting off the compressor. It cycles less in the summer.