My truck just started something new a few hours ago. When I keep the engine at a steady rpm in the range of 1200-2100 rpm it starts to make a sound like a vacuum leak. The higher the rpm, the louder the noise. Letting off or stepping down on the accelerator makes it go away until the rpm's are held steady again.

So when I got home I checked under the hood and applied a vacuum pump to the wastegate solenoid and even after 25 psi of vacuum it still would not open. I reached in and grabbed the actuator rod coming of the soleniod and the damn thing won't budge.

Oh, I have a Banks Big-Head setup.

I'm going to have to unbolt the turbo and see whats going on, aren't I?

Edit - I also forgot the leak sound only happen for about the first 10-15 minutes of driving. It doesn't seem to matter whether I let the truck sit and warm up for a few minutes or jump in and drive off. After the 10-15 minutes have passed it won't make the leak noise anymore. But no matter what, I never seem to hear the wastegate valve opening and the "whoosh" sound when I shift gears (I have a manual trans).

 

This is pointing directly at your exhaust backpressure valve. It's operation is directly related to air and oil temp. When the truck warms up, it is disabled.

 

Oh, I forgot to add, it does not indicate a problem It can activate under low load while driving but is disabled when the PCM determines a load or acceleration is desired. Normal operation. How cold was it?

 

The outside temp or how long the truck has been running doesn't matter. When it was 70+ degrees outside or like this morning when it was in the low 40's it did the same thing. If I start the truck and just let it idle until it warms up or just start it and drive off right away, for the first 10 minutes of driving time it makes that vacuum leak sound.

When I hold at a steady rpm I hear the leak. For example, I accelerate to 1500 rpm and hold it there. for just a second I don't hear anything. Then slowly it builds up and get louder and louder. If I accelerate to 1600 rpm there is a slight hesitation, like the engine doesn't want to speed up, then the vacuum sound goes away. After I hold it steady at 1600 rpm it come back.

Looking back to a week ago when it was still warm enough to drive with the windows down I could hear the blow-off in between shifts. Even though it was cold this morning after I had driven the truck for 25-30 minutes and the vacuum sound was gone, I rolled down the windows and there wasn't the blow-off sound that always brings a smile to my face.

Shouldn't I be able to move the actuator rod by hand even everything was working normal? I have a small Mitsubishi TE04H turbo and I can move the rod on it by hand. Should my Ford unit be able to move also?

If it is the EBV, do I have to remove the turbo to get to it and do repairs?

 

I hope you didn't damage your Banks actuator. It's designed to see a few psi of pressure not a vacuum. But I'm not sure what you mean by "25 psi of vacuum" anyway, because it's only possible to generate about 14.7 psi of vacuum!

The wastegate rod extends from the actuator when enough pressure is applied to the nipple, and moves in the direction towards the turbo to open the wastegate. I used to run a Big Head, but the higher boost helped to ruin my turbo after only 50 K miles! The spring on the Banks is so strong that it's normal not to be able to force the wastegate open by hand, unless you clamp the rod with vice gripes and really push hard.

In any case, I agree with Tenn, that the wastegate isn't the problem. In fact, I doubt that your wastegate ever opens with that Big Head. When I removed mine from my blown turbo, the wastegate valve seat was perfectly shiny with no soot, so it never opened, which is the same as just disconnecting the red line.

If FTE ever fixes the feature to post pics, look for my new post... Surge Analysis, Turbonetics T61, GTP38R, & GT38 w/ 99.5 & Early 99 Wheels, and you'll see why you should go back to a stock actuator and leave the red line connected!

 

Sorry, I meant psi of pressure. It should start to open from 5 psi on but it was not moving even after 25 psi. Nothing moved as I slowly applied pressure to the soleniod.

 

It's like I said, having a Big Head is like having a non-wastegated turbo. Their spring is too strong. When you applied the 25 psi to the nipple did you hear any air leaking from the actuator? The rod does have an adjustable linkage, and IF the Big Head is properly adjusted it might let the WG open some, but most installers adjust them to provide the max possible boost because they think that makes for a happy customer, and then they can sell them a new turbo later on!

I would check the EBPS and clean that tube and check it for holes and leak test it. After going to the trouble of removing it, most just opt for a new sensor and tube.

 

Wastegate is not your problem, so don't worry about that right now. Even when it opens, it's impossible to hear any sound. So that noise you are hearing is something else. In fact, with the wastegate not opening, you should have more bottom end power since exhaust gasses are not bleeding off through the wastegate.

If it's only happeneing for the first few minutes of driving, then it's most likely the EBPV since that is part of the cold air package. Once engine oil temps are over 165*F, the CAP is disabled.

 

Perhaps your engine oil temperature sensor is malfunctioning. This will cause the PCM to activate the backpressure valve which by default is open IIRC. Someone correct me if that is wrong but I believe it is correct. Basically I am saying it should not get stuck closed unless it is commanded there and the solenoid closes it.

 

Only if it's reading incorrectly. If the sensor is shorting out or causing an open loop, the EBPV is disabled completely.

 

Good point Curtis.