Waste gate

[Hillbilly 852]

I have a 95 k1500 s code engine and have been trying to pinpoint a code 78 problem. Had exhaust leak at crossover pipe which is fixed. Have plenty of vacume. Was getting code 78 and 36. Have new solenoid and vacume lines. Got codes to go away by changing the vacume lines location on solenoid. So I know it is not venting. Could the red egr solenoid cause this problem as I know it vents thanks for help

 

[racer55]

More likely that the check ball inside the wastegate solenoid is stuck.
You could try spraying some WD40 into the solenoid ports to free up the internal components.
Make sure the lines are routed this way rather than having the wastegate solenoid vent covered by a vac line.

 

[JMJNet]

Have you checked the vacuum lines?

 

[buddy]

Do you have a boost gauge or know how much boost youre getting? Is the boost low and you get low power and black smoke?

If you have low boost, and the vacuum is good to the turbo actuator, then the actuator itself could be the issue. Check to make sure its solid at idle when vacuum should be holding it closed. If you have vacuum and its still loose then the diaphragm inside is leaking. Or the wastegate itself can get sticky and not close all the way. With the vacuum unhooked make sure it does move freely.

If all of that works, then the MAP sensor on the intake could be reading the wrong boost, and the value fed to the PCM is out of tolerance. A scanner could give you a good idea of this.

 

[Hillbilly 852]

Ok all vacume lines are new waste gate solenoid is new get 18 by at actuator no boost guage first item on my list to purchase. Arm leading to waste gate is tight but can be moved with force. Will move but not easy. Could be a leaking actuator as it is harder to move with lines reversed but can still be moved. With more force than needed to move it before. Bellows black smoke like a big rig when under hard throttle. Still has substantial power though. Could all be working ok and get black smoke from blow by around rings?

 

[racer55]

If the wastegate lever is difficult to move by the finger strength then things to that point appear to be good,has the map sensor ever been changed?

 

[bison]

EGR stuck open maybe,...or mistery gasket blown out?.
Should set a code on the EGR though,..not on the gasket.