I recently installed a turbo boost/vacuum guage on my truck and I have some questions. at psi between 1-3 it reads great but when it gets up higher 4,5 the needle starts to quiver back and forth between 4-8psi. then when I really step on itthe needle goes crazy jumping all around between 5 and 15psi. then just this week I was reading the codes on the pcm and it told me that there was a waste gate solinoid control circut error. Could anybody tell me what's going on or if they've had a problem like that before? And where did you guys tie your lines in? I could only find the one on top of the turbo charger? is there somewhere else where I could get a better reading?

 

your boost line should have been taped into the map line, here's a link to what it should look like

3-Gauge Install Pictures

or you could drill and tap it like here

http://www.dieselmanor.com/diy/PSD3-gauge/image23-a.htm

 

I tapped mine into the AIH delete plug and it works great. Nothing like you was talking like.

 

Did you buy a cheap boost gauge? When you checked your codes did you write the numbers down? Need more info on codes.

 

Yeah, the gauge is suspect here -- we don't have any vacuum, so no vacuum gauge needed. But then again, if the wastegate is opening when it shouldn't, you'll get some strange boost problems. However, it probably wouldn't be too jumpy -- I would think it would move around a lot slower, and likely cause a low boost issue if the wastegate is opening too soon.

 

Oh yes it runs off of Boost I was changing out boost gauges and had to drive a little bit without the gauge let me tell you you got some turbo whistle lol.

 

I would sugest getting an Autometer if you have not already done that and tap into MAP tube.

 

only line I can think of on top of turb is waiste gate line,which is red,you don't want to tap ino that one

 

did it blow dry your hair when boosting

 

I was just curious I ended up plugging the line.

 

sounds like you plugged it into the wastegate line, be it the red one or green one...

 

Your code indicates a potential issue with the wastegate control feedback system which operates as follows. The wastegate actuator canister has a red line running to it and the canister has a spring inside which normally holds the wastegate closed. The other end of the red line goes to the wastegate control solenoid on the spider. The solenoid also has a green line that runs to the large black rubber hose going to the turbo intake, and the solenoid also receives manifold pressure from the spider.

As far as I can tell the solenoid functions like a double throw switch. In one position it connects the actuator canister to the manifold pressure in the spider through the red line, and in the other position it dumps canister pressure back to the turbo intake through the green line.

The PCM continuously pulses the solenoid to switch between these two positions at a rapid rate and this constitutes a so-called "bang" feedback control system. Bang the solenoid connects the actuator canister to the manifold pressure in the spider and then bang it connects the canister to the turbo intake hose.

The PCM adjusts the degree to which the wastegate opens by varying the duty cycle of the bangs to favor either the above atmospheric pressure in the spider or the below atmospheric pressure in the turbo intake hose. The PCM varies this duty cycle until the PCM sees the MAP reading that it expects to see for the given engine load.

Under typical operating conditions the pressure going to the actuator through the red line is between about 5 psi to 8 psi. When the pressure in the red line exceeds 5 psi the wastegate starts to open and when the pressure in the red line reaches 8 psi the wastegate is fully open. Note this is psi in the red line, not boost pressure in the spider.

The easiest way to see if the wastegate control feedback system is faulty is to use a piece of hose to connect the nipple on the canister where the red line normally goes directly to the one on the spider where the solenoid receives its manifold pressure. Then as you apply the throttle the wastegate will be controlled directly by the manifold pressure and your boost gauge should rise smoothly to about 12 psi or so. Even though the wastegate is fully open at a boost of 8 psi the boost still increases above that. At least it did on my truck with a 70 HP chip installed.

 

Yeah, it does sound like he tapped into the wastegate line, I could see how it would cause wastegate codes. Also, the wastegate is a PWM valve, so it will get pulses which will show up as the OP describes on the gauge.

 

Yep I'm tapped into the wastegate line Where should I tap into and what do I do to fix the red line?

 

Tap into MAP sensor line. If you just unplugged the red line, plug it back in. If you cut the red line, find some 1/8" vacuum line and repair the line, or just cap it off and not worry about it. Just make sure to keep it from leaking boost.