Skrillah

Hey guys,

I have this weird noise coming from the engine bay and I can't figure out what it is. It literally sounds like a cricket is under the hood chirping. Its not belts I'm sure. When I accelerate I hear it but it comes and goes with acceleration.

Could a vacuum leak or air intake leak cause this kind of sound? I'm also thinking of replacing the PCV since its been a few years. I don't know if any of these things would cause this type of noise though...

I'd appreciate any suggestions or tips. Check my sig for specs on the truck..

Thanks, Kyle

DeathCougar

iTrader: (23)

Usually its caused by a loose belt. I know you said you know its not, but how do you know? I would remove the belts on by one to see if the sound goes away.

24Runna

Old belt too DC. The tension was good on my old belts but they were old and cracking.

Skrillah

Yeah, the belts were replaced last month. I suppose I could check the tightness of them but thats why I replaced them...cause they were squeaking or so I thought.

Its not like a squeaking noise....its almost like a chattering whistling noise.

I know these 2.7Ls are due for valve jobs once at the higher mileage but all that appears to be normal. There is no abnormal ticking or anything like that. Nor is there a rough idle or codes being thrown.

24Runna

Check the tension then. Make sure its relativity tight.

cosmophonic12

I have the same problem but with my 5speed 4Runner, but you have auto transmission right?. theres some linkage between the clutch and the transmission thats out of grease. if i lightly push clutch pedal, it gose away. some ppl say its throw out bearing too. ive put 40k miles sine the "chirp" and no problems, just that noise. you will also find more info about this subject if you search too. if you have an auto like your sig line, i dont know what to tell you.

skrassow

My taco has been doing this for the last 70k. Drives me nuts but it cant really be fixed. I took it to a dealer once and they said it will just come back in a few thousand miles. Man I wish I could make that go away!

98.T4R

my 4runner does somthing similar but i think its a whstle in the throtle body. it hapens at certin rpms and and when i give it just the right amount of gas.

Skrillah

Yeah that sounds about right...it sounds like its coming from the throttle body...but what would cause it other than a leak? I am going to replace the pcv valve to see if that makes a difference.

98.T4R

i was thinking it was the air flow around the butterfly. I also started hearing it after i did the deckplate mod. can you get it to make the noise if you play with the throttle when your driving?

Skrillah

Yeah man, I think you hit it on the head.

If I give it gas almost anywhere during the driving range, I hear it. I don't know if there is a fix for it or not. Do you have the 2.7L? Do you think its literally from the butterfly valve or its an actual leak around it? The funny thing is I've noticed it happening since I cleaned the throttle body a week or two ago. Perhaps there was carbon buildup that helped to seal it better. If thats the case, I'd probably just have to replace the valve (if you even can) or more than likely just replace the TB itself to get rid of the noise. Although, it may not be worth it as long as I'm not loosing performance or MPG from it...

98.T4R

i have the 3.4, but never thought much of the noise until this thread. but now that you mention it i have noticed the noise after i cleaned my throtle body to about 3 months ago. i dont know if its a leak or what. im cerious now to. my TB was dirty for so long the butterfly wore into the side of the TB and like used the dirt and such as sand paper, so now i constantly have a high idle unless i blurp the throtle to get it to close all the way. so i think im gonna replace the TB and see what comes of that noise.

Skrillah

coo man...please definitely let me know what kind of results you get.

I replaced the PCV today with no improvement...

Again, I still don't notice much in the way of performance loss...or so I don't think...

Skrillah

After doing some more poking around today...i think my sound is coming from the silencer on the intake system. Which would make sense as to why I'm hearing the noise now after a throttle body cleaning as I may have very well cracked some of the piping or a seal broke loose. More in depth diagnosis to come.

toytim

I had Crickets in my engine and it was the idler pulley under the timing belt cover.. A little bit of this and a little bit of that and they vacated..