Odd Sound At Idle. Gurgling?

[hEaT]

At random times when my car is idling at the normal idle (no A/C on and no bump for cold starts) it sounds like the car is trying to suck air through water. I popped the hood and the sound is definitely coming from the air filter. If blip the throttle it stops immediately, but then returns after the idle resettles. It's been doing this for almost 6 months now with no ill effects that I can tell. In the past few days though I've noticed the car is starting a bit harder. It seems like it pops first and then starts up. Mods are just a Volant intake and SVT Borla exhaust. The filter hasn't been cleaned in about 20k so I'm going to take the filter off and see if it still does it. If it does, I'll take a look at the TB and see if there is anything there that could cause the sound.

Other than that, I don't know where else to look. Any suggestions? Fuel filter? The pump was changed under the recall recently and when the pump was bad I did not have the sound. Vacuum leak? I do have a CEL on for a minor EVAP leak...I believe that it has to do with the pump since when I fuel up I can smell fuel for a while, but nowhere near the engine bay.

I searched here and found something about a TSB related to the A/C causing this noise. To rule it out I ran the A/C the other day for about 5minutes and the sound is still present.

[boosted00focuszx3]

have you cleaned your maf recently, might be related to your cold start issues especially since its getting colder lately.

[hEaT]

Never cleaned it. Car runs fine though. No stumbling at any RPM or throttle position. My roommate should have some CRC MAF cleaner I can use.

[EuroAyres]

is it like a hollow popping from the airbox every once in a while...itll almost sound like a reallly toned down backfire??? If so i have the same issue. I have cleaned my air filter, checked plugs, new fuel filter. Still happens..and when i rev it a little it goes away, but usually comes back as soon as the motor settles back down to idle.

[hEaT]

Sort of. I'll try to get a video of it this weekend or Friday. I'll be pretty busy the new two days and daylight is hard to come by.

[boosted00focuszx3]

Originally Posted by hEaT

Never cleaned it. Car runs fine though. No stumbling at any RPM or throttle position. My roommate should have some CRC MAF cleaner I can use.

just figured it might be related to the hard start issue. That stuff works wonders my fathers 97 contour zetec was very slow/hard starting the crc maf cleaner worked wonders. The black crap that came off the maf was rediculous.

[FordFociSHO]

Put a vacuum gauge on the intake manifold once and tell me what you get for idle vacuum. Compression test too if you can.

I have an idea but don't want to alarm you, probably did already though.

[EuroAyres]

Im guessing your prob talking about the intake valve seals fordfocisho??

[FordFociSHO]

^^um, no (stem seals?) you got 2 of the words right though just missed one

[hEaT]

Hmm, the problem has stopped...for now.

I'll be ordering a boost gauge soon for my XR and I'll throw it on the Focus and get a reading before I put it in the XR.

[hEaT]

Doing it intermittently again. Not constant at idle like it was before, but after I rev the motor, it will pop a few times when returning to idle then gurgle at random times for a few seconds. No drop in idle rpm, no drivability issues, power seems fine, and no CEL's.

Doing pretty much exactly what you said now EuroAyres.

Motor does have 90k on it, but sees Mobil 1 5W-30 every 3k miles with filter.

What would be the replacement procedure for valve stem seals? Also, would this be anything I could diagnose by data logging with an XCal 2?

[EuroAyres]

i just dont understand if it was that wouldnt there be any kind of loss in performance and idle consistancy...mine is exactly like yours heat and it kind of scares me. Mine never did it untill i put in my copper plugs and k&n panel filter. Plugs are fine, filter is fine....I just dont get it but would like too. And it only happens sometimes..wouldnt that suggest its not the seals, although it does seem to happen when the motor is at operating temp....enlighten us fordfocisho please..i want to figure this out before i spend all of my money on the rest of my turbo project and really cause some damage.

[Johnny_P]

my car makes some dumb noises at idle.... a LOUD ass sucking sound, its a lot like you describe but nowhere near a backfire noise. Very deep. I did some research and I think its probably a stuck or slightly clogged idle air control valve. I would have replaced mine but A) I don't care, and B) I'm too lazy to take off the intake manifold

[hEaT]

That's what Demonfire suggested to me as well. No CEL's yet for any IAC problems.

[FordFociSHO]

With the IAC you should be able to moniter duty cycle with the xcal, as long as it consistent it should be fine, though I'd say if you see something like 80% you got problems.

I was going to say slow port speed/poor mixture quality. A lot of times when you put an intake system on the piping is larger in total internal volume, which slows the total air speed at points, like idle. If you play with the intake cam some you can get rid of the sound and maybe pick up a few hp. I know at stock settings mine made a similar sound and if I retard the cam it gets worse. IIRC it also has to do with cam overlap.

But it could also be the valves/seats themselves. I've seen a few instances where improper seating of the valve made some weird sounds, but didn't affect compression. It's like the valve face is seating slightly off, bent but not really, more like the cuts are off. Like if you toss custom valves in but don't get the seats matched to the valve. If you haven't had the head appart though, don't worry about this one.


And I don't think the IAC will throw a CEL until it almost totally fails. As long as the ecu can still compensate for idle speed it consideres the IAC in good working order, even though duty cycle may be way off.

[hEaT]

Ok cool. I'll have to get my USB cable then and I'll datalog the IAC. I've had the valve cover off to do the gasket, but the sound didn't start until maybe a year after that so I don't see any correlation. I've never had the head off or touched cam timing.

[hEaT]

Got the USB cable for the life of me I cannot get that stupid ****ing program to work. I can build an entire computer and get it up and running from scratch yet I can't get the SCT program to connect to a USB device...what the ****?

[EuroAyres]

Please heat when you get this done let us know so I/We can know if i need to tear the head down for seals or replace/clean a valve.

[hEaT]

Yeah, I will. I was all ready to data log the IAC duty cycle...if the program connected.

[EuroAyres]

Thanks hEaT. If this is just an IACV then i will be so happy, becuase its not the seals..which i really dont want to tear my head down. BTW does anyone know the cost of a SVT IACV????

[Johnny_P]

^ best bet is to ask Steve (FORDSVTPARTS)

hEaT, keep us updated on what you find!

[orionlion82]

i hear my fuel tank gurgle when i come to a stop and shut it down.

[EuroAyres]

This sound is comming from the intake/ intake box.

[hEaT]

Mine is doing it under cold starts as well, but not so much during warm idle. This leads me to believe it has something to do with the IACV and not a internal engine problem.

Still fighting with the datalogging software so I don't have a definite answer.

[EuroAyres]

I have not even listened to it at a cold start on mine yet..ill do so today. I also forgot to mention that sometimes when on the freeway and im getting off a ramp, i push the clutch in and the car stalls...i think this is a sign of a sticky/bad IACV isnt it?