PDA

View Full Version : Wastegate solenoid vac hose question..


rameye
08-31-2005, 10:22
I scoured my manual for a vacuum hose routing diagram....no luck.

I'm persuing a code 78 and just wanted to know if the vacuum hose connections to the wastegate solenoid can be reversed?

Does it matter what side vacuum is applied to, or because it is an inline valve, it doesn't matter.

I noticed it has 2 different sized ports.

Thanks in advance
JohnC
08-31-2005, 10:51
Originally posted by rameye:
I scoured my manual for a vacuum hose routing diagram....no luck.Didn't we just cover this the other day? ;)


I'm persuing a code 78 and just wanted to know if the vacuum hose connections to the wastegate solenoid can be reversed?Yes, they can. (read on)


Does it matter what side vacuum is applied to, or because it is an inline valve, it doesn't matter.Yes, it matters. It is not an inline valve. It alternately connects vacuum to the wastegate and vents the wastegate to the atmosphere. If you get it backwards it'll vent the pump instead and boost will be too high -> DTC 78


I noticed it has 2 different sized ports.The smaller (restricted) port must be connected to the vacuum source. The unrestricted port goes to the wastegate.
BobND
08-31-2005, 10:55
The "duty cycle solenoid" alternately connects the port to the waste gate actuator to the vacuum source, or free air.

The greater the duty cycle, the greater the % of the time the port is connected to vacuum, and the greater the average vacuum to the turbo wastegate is.

So, the valve is basically a 2-way valve, and won't function as intended if the connections to the vacuum source and wastegate ports are reversed.

Not sure about your '95, but the solenoid's port closer to the front connects to the vaccum source on my '94 K-1500, the rear port to the wastegate actuator.
rameye
08-31-2005, 13:46
Got it..smaller port to vacuum source, big port to wastegate.

Many thanks...

Does it specify that any where in the Helm manual?
Barry Nave
08-31-2005, 19:04
I fell for you guy's, tracking down a code 78.
I just gave up ;) Gone for ever :D
rameye
09-01-2005, 13:44
Dont quit, it's the code that keeps on giving!