Finished hose job, now tractor noise
 

Hey guys,

I just finished doing my silicon hose job. The engine looks much better now, hopefully the longevity is increased, and I sure learned a lot about where stuff is on this car. Also in the process I put in an HKS RS Intake. Now that I have everything back together, the engine starts right up and idles fine. The car also drives just fine too, but I haven't gotten on the boost yet.

Now for my question. At idle I'm now getting a tractor like noise coming from the passenger side of the of the engine. It's almost as though the injectors were clicking REALLY loudly or one of the turbine blades was scraping the side of the turbo housing. So, if I hooked some connectors up backwards (the wastegate and turbo precontrol connectors come to mind), could that cause that noise some how? Could air somehow be flowing backwards through one of the turbos? I can't really imagine how, but I thought I'd see what you've all got to say. Thanks!

At idle, turbo airflow shouldn't be an issue. Make sure it isn't an airpump noise - unplug the airpump and see if anything changes.

Dale

Well, I unplugged the airpump and the idle went down a little bit. Because the idle went down, the engine noise went down a little, but the clicking tractor noise stayed at the same level, thus making the clicking noise a little more noticable.

I also tried flipping the wastegate and and precontrol solenoid connections around and that didn't make any difference.

I did notice that when I really shove my face into the engine bay, right over the turbos, I can smell exhaust. I'm wondering if maybe there's a torn or missing exhaust gasket and the noise I'm hearing is just the exhaust noise up in the engine bay.

As part of the hose replacement, did you remove the ACV? Does the noise appear at a certain RPM?

If so, the disk in the ACV may have slipped and it makes a racket!

ACV = the valve on the underside of the UIM?

If so, then yes, I did remove that and replace the gasket. What do you mean the disk could have slipped?

And yes, the noise seems to get quieter as RPMs go up. Mainly I notice the noise at idle.

The Air Control valve is toward the passenger side of the rats nest attached to the lower intake manifold with 3 studs.

You can read about this issue HERE in Chris Davis's section.

Ok, well I went and looked in the FSM and I did not actually take off the ACV. Of course, that doesn't mean the check valve didn't happen to bad right now. I didn some searching and some guys in the second gen forums had some problems with the ACV and were experiencing symptoms very similar to mine.

Anyone else had this happen to them?

Ok, well I did some more searching around and I'm sure this is an exhaust leak now. I got under the car, and I can smell exhaust from right below the turbos. I can also smell exhaust if I put my face right above the UIM.

I checked all three actuators for the turbos to make sure the rods were still in place. I read that sometimes those can come off and rattle around. Not that.

On some other thread I found the idea of using a piece of hose to act as a stethoscope to try and isolate the leak. I grabbed a 2ft piece of fuel line I had laying around. Using that technique, I couldn't find anything under the car. From up above though, I found that if I shove the hose under the UIM, I can hear a hissing sound.

Could that be exhaust escaping from the ACV?

I have the clicking sound when my car was stock. Not a very loud one however. Also curious

Well bad news. I just pulled everything apart again and it wasn't the ACV disk. The disk was seated nicely over the hole.

The only other thing I discovered was that one of the nipples on the solenoid that sits on top of the ACV was cracked. I broke the nipple pulling the hose off. Anyone know what that solenoid controls? What would break if one of the nipples was leaking air?

Turbo control solnoid