2001 Excursion 7.3 with Banks Powerpak including Banks Big Head wastegate actuator. Truck is running OK, but doesn't seem to have the power it used to. Boost only gets up to 20ish psi w/100hp chip. As I recall banks said it should be more like 22-24psi, maybe even 26. In cold weather while the motor is cold I can hear a hissing while driving and the engine is barely under load - I can make it stop by accellerating or decellerating. It only hisses in that "neutral" zone.

I'm trying to evaulate the wastegate to make sure it's working properly - I'm suspicious that it's not fully closing and bypassing the turbo limiting boost. I disconnected the red vacuum line to the actuator - there was black soot in the line. When I put a hand vac on the actuator it held 20 inches and nothing moved. Should the shaft move?

I have the EBPV sensor and line pulled right now for cleaning - it was by no means plugged, just average crud - but nothing that should limit air movement. Do I need to perform further checking of the EBPV?

I do have a low boost pressure code too, but I've been told that's not uncommon given the intake, exhaust, and chip.

 

There shouldn't be any black soot, or residue of any kind, in the red line going to the WG actuator. Only clean pressurized air from the intake spider should be diverted thru the WG solenoid to the actuator. It is pressure that moves the actuator, not vacuum. Sounds like the EBPV valve is closing. Have you tried unplugging the solenoid at the base of the pedestal and see if the noise ceases?

 

I'm not 100% sure there is a problem with the EBPS, but I though this would be a good opportunity to clean it out. Any idea what the black soot is an indication of? I'm surprised the wastegate is activated by pressure given the connectors - they are just push-on connectors like a vacuum connector. How much pressure does it take to move the wastegate shaft, and should I be able to move the shaft manually? I cannot move it now.

 

A few weeks ago a buddy stopped by with his 2001 Excursion because the check engine light was on. The only code found was P1247 (Turbo Boost Pressure Low). He replaced the fuel filter and the light went off and normal boost was restored. The engine has been running fine ever since.

I am not sure your issue is the same so I am just throwing the idea out there because sometimes it's the simple things that we overlook from time to time.

 

Here is some info about how the waste gate solenoid and valve work.

 

Greg,

Thanks for the reminder. I forgot I had this WG info. While saving the PDF I saw I already had it.

 

Should I be able to move the wastegate shaft by hand with the engine off?

 

I do that all the time as well. I really need to organize my electronic files a little bit better.

I am not sure (never tried it). I have the Big Head waste gate on one of my trucks...I'll check it when I get home and see if the shaft moves.

 

Yes, if you pull it in the direction of the wastegste. The WG actuator pushes the rod to open the WG. The bias spring in the actuator keeps it closed by pulling it. That spring has much more resistance then you would think and takes quite a pull to overcome.

 

If you want to see if the actuator will push the rod to open the wastegate remove the red line and use compressed air right on the actuator. Start at 5 PSI and dial up the compressors regulator. Don't exceed 20 PSI or you might damage the actuator diaphragm. Turn the compressor regulator up and down and the acuator rod should move in and out.

I wish I could remember at what preussure the WG should start to open and at what pressure it should be fully open. Does anyone have those numbers?

The previously attached WG PDF states:

"The PCM will control the boost pressure by duty cycle to the solenoid to maximize boosting performance (no more than 16-1/2 psi)".

How would you interpret this? Does the 16 1/2 psi refer to the turbo boost or the pressure on the red line????? I've seen stock trucks get more then 16 1/2 PSI of boost so I'm confused about this. Maybe over 16 1/2 PSI of boost means the WG solenoid or the actuator aren't properly fucntioning. Hell, I don't know. Like I said, I'm confused.

Can anyone help me get un-confused?

 

Dang, Robin now you have me confused!! LOL.

 

Thanks Grady. At least I know I have company.

Nine hours between my post and yours.

Makes me believe we're not the only ones confused.

Just the only ones to admit it.

 

Just adjusted my stock wg rod couple weeks ago. I too put regulated psi to it and it was about 4lbs is all to get some movement and it seemed like it was moving alot by 7psi. So I took it off and adjusted the rod..that rod is staked in place...I had to chase them threads before I could get much forward adjustment...It has made some noticeable improvements in accelerating ....not doing much in performance till I get the bugs out and guages and dp tunes....sorry, what a hijack

 

This is a video that I remember seeing a while ago, it is not mine it is Kwikkordead's, it shows exactly how it works.

7.3 Waste gate adjustment - YouTube

 

Thanks for posting that video Donn. That demonstrates what I was talking about in my post about using compressed air on the actuator to test the opening and closing of the WG. It also shows you can apply up to 25 PSI without harm to the acuator diaphragm.

It also, at least to me, means that the 16.5 PSI max in the WG Operation PDF is referring to turbo boost pressure. When the PCM via the MAP sees 16.5 PSI of boost it starts opening the WG via the WG solenoid and the WG actuator. Since the WG solenoid has a duty cycle then the PCM adjusts the WG opening accordng to the boost. The WG solenoid will apply more or less pressure via the red pressure line to vary the amount the WG opens.

In this service manual it says to adjust the rod so that just 5 PSI applied to the actuator starts to open the WG. But to each his own. Hence why there are posts about how to adjust the WG control rod so it doesn't open until a higher pressure.