Intake noise

[backroad101]

Since this has moved away from being a pulley noise, I am starting a new thread.

Quick rundown. Have had a groan under the hood for a month or two. It is not constant. Comes and goes and I can get it to stop if I hit the gas a little. No driveability issues, check engine lights or leaks that I can see. Research on here led me to replace the idler pulley. After that I did the belt tensioner. No luck. Cheap trial and error so no biggie

Today I get to work and noise starts. Pull in and pop the hood. Probe with the stethescope and nothing really jumped out. Put my ear to the airbox. Hmmm. Open the airbox (seperate up and lower parts of airbox), and there's the noise coming from the intake somewhere. Thoughts on the issue? Someone suggested the PCV? I have also replaced the IAC in April after an idling issue.

Thoughts? 99 XLT 4.0L OHV automatic

 

[feellnfroggy]

pul the silencer if its got one. check for blockage in theairway.

 

[backroad101]

Where is the silener? Is it in the upper part of the airbox or the intake tube? If it is in the bottom half of the airbox it's prob not the problem as I still have the noise with the airbox open

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[backroad101]

http://www.therangerstation.com/forums/showthread.php?t=44289

It's in the box itself, so prob not my issue.

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[feellnfroggy]

Anyway you can get a vid of the engine running, we need sound from this point on. THe only other thing you can do is inspect the entire intake pipe from the box to the throttle body.

 

[backroad101]

I'll keep the camera in the truck and see if I can catch it doing it and take a video.

Now that I have figured out where the noise is coming from, the plan tonight (provided it makes the noise) is to take the intake tube off while the truck is running and making the noise and see what happens

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[feellnfroggy]

I'll keep the camera in the truck and see if I can catch it doing it and take a video.

Now that I have figured out where the noise is coming from, the plan tonight (provided it makes the noise) is to take the intake tube off while the truck is running and making the noise and see what happens

.

Its a 99 so witha MAF system anything you take off after the maf while running is gonna send you into limp mode, it will run like absolute shyt and you prolly wont be able to diagnose that way. I would just completely dismantle your intake and check everything then put it back together and see if anything changes. You gotta be smart about how you handle those stupid emissions systems.

 

[feellnfroggy]

sorry double post

 

[backroad101]

Yeah, took the tube off and the engine died. If I disconnect the MAF sensor then take the tube off, the engine will stay running. Unfortuantly the noise gone there when I restarted the engine.

Anyway, here is a video of what I have. Maybe TB sticking slightly open?



Let me know your thoughts.

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[98 ranger xlt]

Try cleaning the IAC.

 

[backroad101]

As noted above, the IAC is new, replaced in April 2010. When it went bad it I had a code and driveability issues, none of which I have now.

Will give it a shot though as I clean everything else around it

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[backroad101]

So turns out it was the IAC. Guess the one I bought in May was bad. Never thought to use the camera as a stethascope.





Gonna exchange it tomorrow.

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[Stxrangerbumper]

(iac) change it, its probably your problem after you change your truck will no longer be tiring noise.This gadget is a small cylinder that moves and can make a sound similar after a while

 

[backroad101]

Just an FYI, don't buy the IAC from Autozone that is $42 (TV245). Apparently there is not a warranty on it. That's what I bought in May. Guess I assumed it had a warranty as everything seems to have at least a 1 year. Lucky they were having an issue pulling up my sale and the part in there system so they just assumed it had a 2 year warranty and swapped the part for me.

All seems to be good now

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[backroad101]

So after a year my IAC seems to be making noise again. What would cause these to fail? First one went bad after a couple months and I accepted it was just a bad part. But now this one is making noise after a year. Thoughts?

Engine is stock including air filter (no K&N or anything) Only thing that has changed that I can think of is the weather