Buzzing...??!!

liberty2.8 · **Posted:** Sun May 02, 2010 2:53 pm

Okay, I need some help diagnosing this problem that just started today. After turning off the engine, there was a buzzing noise coming from under the hood. It stopped after about 15 seconds after turning engine off. So I popped the hood and turned engine back on. I could hear the buzzing over the engine sound. I turned key off and noise continued for 10-15 seconds then stopped. I turned key back on but not all the way to start engine, to find source of noise which seemed to be near fuel filter. Through touch, I think I narrowed it down to some elec. part/valve inline with the intercooler hose directly forward of fuel filter. This part has a harness plugged into it.
What is this part and what is the buzzing? Engine seems to running fine right now.

CATCRD · **Posted:** Sun May 02, 2010 7:05 pm

Sounds like your FCV has locked up. (egr flow control valve). It's like a throttle plate in your intake. Expect a CEL one day from it, or a $500 repair.

liberty2.8 · **Posted:** Sun May 02, 2010 7:34 pm

Is this the same thing as the EGR air control valve? Found it in the sevice manual but not sure if this valve can be serviced/cleaned or does it just go bad?

geordi · **Posted:** Sun May 02, 2010 8:16 pm

I have a spare one that I could sell too. I don't want to sell the one that is on my engine now, even tho it is unplugged and the center disc is pulled. I suspect that something is broken in that one, b/c when I had it off the engine a few days ago I thought I heard something loose inside it's casing. That didn't bother me b/c I was pulling the center disc, but for anyone who wanted it to work... It might not. The spare is fully stock however, and it is easy to install.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

No check engine light?

The intake throttle will make a buzzing sound after shutting off the engine typically for about 5-10 seconds and sometimes longer if the ECU performs long diagnostic routine. An easy check to see is it is still working is to disconnect the CAC hose and watch the throttle flap right when the engine is keyed off, the throttle shut shut and then open after a few seconds.

liberty2.8 · **Posted:** Sun May 02, 2010 8:57 pm

geordi wrote:

I have a spare one that I could sell too. I don't want to sell the one that is on my engine now, even tho it is unplugged and the center disc is pulled. I suspect that something is broken in that one, b/c when I had it off the engine a few days ago I thought I heard something loose inside it's casing. That didn't bother me b/c I was pulling the center disc, but for anyone who wanted it to work... It might not. The spare is fully stock however, and it is easy to install.

So are you saying that the FCV is not necessary? If not, I might just consider disabling it.

liberty2.8 · **Posted:** Sun May 02, 2010 9:02 pm

GreenDieselEngineering wrote:

No check engine light?

The intake throttle will make a buzzing sound after shutting off the engine typically for about 5-10 seconds and sometimes longer if the ECU performs long diagnostic routine. An easy check to see is it is still working is to disconnect the CAC hose and watch the throttle flap right when the engine is keyed off, the throttle shut shut and then open after a few seconds.

Yep, I have a CEL but because of ORM and probably other things:( I'm thinking of replacing the MAP after reading your thread warning of improper cleaning methods of the MAP. This buzzing sound is not like any noise that existed before today but it is definately coming from the area of FCV. It's almost like a solenoid that is stuck; I'm guessing its actuated by a solenoid switch. You can feel the vibration on the housing.

Sir Sam · **Posted:** Sun May 02, 2010 9:51 pm

If your like me you got tired of the buzzing, so I unplugged it. Problem solved. CEL still on from that though, and the ORM.

geordi · **Posted:** Sun May 02, 2010 9:54 pm

I have an SEGR, so I am not getting an error code about the FCV even with the GDE eco-tune. However, I have recently switched to using the bypass plug for diagnosis of the power loss issue that is STILL bogging me. The instant I put that in, I started getting this: "P1140 Exhaust Gas Recirculation Throttle Control Circuit Open" as the code. I never built the bypass plug with the EGR power wire connected to the plug, so this is technically correct.

Notice - I don't seem to have an FCV related code. I don't know why, but with the FCV unplugged and the SEGR connected... I have never seen a code about the FCV. Right now it is plugged in, but the shaft doesn't have anything on it, so the ECU can "think" it is working, IF the motor doesn't have broken gears... But it is incapable of changing my intake performance for the worse. Just like I want it.

KeighJeigh · **Posted:** Mon May 03, 2010 1:45 am

Just so I know I'm reading this properly. The Flow Control Valve / EGR air control valve (The manual refers to them by both names) to the EGR should NOT make any sound? Because mine definitely does with the key on.

liberty2.8 · **Posted:** Mon May 03, 2010 12:03 pm

Quote:

Just so I know I'm reading this properly. The Flow Control Valve / EGR air control valve (The manual refers to them by both names) to the EGR should NOT make any sound? Because mine definitely does with the key on.

Maybe mine has always made noise but not noticably until yesterday. Now you can hear it over engine noise and especially after key has been turned off for 10-15 seconds.

liberty2.8 · **Posted:** Mon May 03, 2010 12:42 pm

geordi wrote:

I have an SEGR, so I am not getting an error code about the FCV even with the GDE eco-tune. However, I have recently switched to using the bypass plug for diagnosis of the power loss issue that is STILL bogging me. The instant I put that in, I started getting this: "P1140 Exhaust Gas Recirculation Throttle Control Circuit Open" as the code. I never built the bypass plug with the EGR power wire connected to the plug, so this is technically correct.

Notice - I don't seem to have an FCV related code. I don't know why, but with the FCV unplugged and the SEGR connected... I have never seen a code about the FCV. Right now it is plugged in, but the shaft doesn't have anything on it, so the ECU can "think" it is working, IF the motor doesn't have broken gears... But it is incapable of changing my intake performance for the worse. Just like I want it.

geordi, are you saying that the SEGR disables the FCV? I just went and unplugged the harness going to the FCV and buzzing stopped. What are the risks of running with the FCV unplugged?

geordi · **Posted:** Mon May 03, 2010 1:42 pm

From what others have said, the SEGR doesn't disable the functionality of the FCV for it's "smooth shutdown" purposes. However, I have the suspicion that the FCV helping with shutdown is more of a myth. The VW Jetta TDI has the same basic device, but it is not set up as part of the emissions controls. (At least it wasn't on the 01 that I had) and I drove that car for 150k miles WITHOUT that thing... The shutdowns were no harder than with it.

I just powered off my CRD (sitting in it while waiting for laundry) and I guess it does have a bit of a 'rumble' when it is stopped... I've never really noticed it before, and with so long operating without one on my Jetta and almost 50k miles on this one (83k total on the odo now) I don't think it is causing any problems. I think they put it there to try and make our diesels more smooth-gas-car-like. EWW. But here is the MAIN use in our CRD:

It chokes off the intake air supply when the EGR is activated, to force even more filth getting sucked into the cylinders. This is a function I CANNOT allow to continue if I have a choice. To keep the stupid nanny-computer happy, that is why I plugged it back in, but have not ever seen a code for it show up even when it was unplugged. I don't know why I haven't been getting a code for it however. Maybe that code I posted IS the FCV code, and I'm reading it wrong b/c they refer to the FCV as an EGR device in the service manual. *shrug*

I haven't had any problems by running without it, and it seems like others haven't either. Why some seem to have an idiot light and I don't... Dunno. But mechanically, there doesn't seem to be any GOOD reasons to keep it.

KeighJeigh · **Posted:** Mon May 03, 2010 4:28 pm

Last night I unplugged both the sensor and the control valve - something I've never done before. WAY more power! So I'm not sure what to think at this point . . ..

geordi · **Posted:** Mon May 03, 2010 4:40 pm

KeighJeigh wrote:

Last night I unplugged both the sensor and the control valve - something I've never done before. WAY more power! So I'm not sure what to think at this point . . ..

Wait now - Which sensor, which control valve?

Because so many different names are used for the stuff on this engine, can you describe the locations of the two things you unplugged? I have logging SW that I would be happy to use on mine to compare before / after in addition to the analog boost and EGT gauges which have been a fairly good indicator of the engine's power on mine.

stoutdog · **Posted:** Mon May 03, 2010 4:49 pm

Hrm.... geordi,

If our EGR valve is disabled (via ORM, SEGR, or GDE) should we have to worry about the FCV's "main" operation, as you described it?

Thanks.

KeighJeigh · **Posted:** Mon May 03, 2010 5:03 pm

geordi wrote:

KeighJeigh wrote:

Last night I unplugged both the sensor and the control valve - something I've never done before. WAY more power! So I'm not sure what to think at this point . . ..

Wait now - Which sensor, which control valve?

Because so many different names are used for the stuff on this engine, can you describe the locations of the two things you unplugged? I have logging SW that I would be happy to use on mine to compare before / after in addition to the analog boost and EGT gauges which have been a fairly good indicator of the engine's power on mine.

100 different sensors and 200 different names!
I unplugged the sensor on top of the air filter - the mass flow sensor. This is generally what is referred to as the ORM or off road mod since it is illegal. This is supposed to close the EGR. However, I've read that it doesn't actually fully shut it down- just mostly shuts it down . . whatever that means. It also throws a code. The SEGR kit shuts the thing down completely and fools the computer so it won't throw a code. (I have the kit but will need to review my electronics and place some serious time asside to put it all together and mess with the wiring harness)

The control valve in shown in the picture I posted above is what I unplugged. The plug for it is located on top of the valve. No more buzzing when I turn on the key and way more power. I didn't notice any shut down issue if that is what it is supposed to help with. Just a lot more power. But, I'm not sure what the implications are of this. . ..

CATCRD · **Posted:** Mon May 03, 2010 6:42 pm

The FCV should make a nice clean electrical whine for a few seconds after you shut the engine off, and then end with an audible click as the throttle plate springs back open.

If it's making an angry bee sound that it never made before, the gears are probably locked and it will eventually burn out. It's probably locked in the full open position, so you'll never notice a performance loss, but when it eventually does burn out you'll get a CEL with P1140.

boilermaker2 · **Posted:** Mon May 03, 2010 7:48 pm

I concur with CATCRD. Every night when blackie goes to sleep, she buzzes then clicks after I've shut her off, removed my key and begin to get out of the vehicles. She's done it for 4.5 years. This is normal. I have done the ORM disconnect and she still does it. I have not done the EHM so she may eventually go out. However, I do keep the oil changed and use high-grade 5% biodiesel with the dino oil pumped and cracked right her in the ol' USA. This will hopefully allow a few of these internal parts to keep buzzing and clicking for years to come.

liberty2.8 · **Posted:** Mon May 03, 2010 10:23 pm

Quote:

If it's making an angry bee sound that it never made before, the gears are probably locked and it will eventually burn out. It's probably locked in the full open position, so you'll never notice a performance loss, but when it eventually does burn out you'll get a CEL with P1140.

Yep, more like the angry bee sound. I unplugged the harness today and all is well. Never have heard the nice clean electrical whine for a few seconds after you shut the engine off, and then end with an audible click as the throttle plate springs back open. Guess I'm either deaf or mine has just been very quiet.

Buzzing...??!!

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