I have a 96 GMC 3500 6.5 196K miles. I recently replaced the vacuum harness and wastegate solenoid because I broke the old plastic lines handling then too rough.

Any way my question is that I noticed I am getting some vacuum but not much at the wastegate. It is so little that while the truck is running you can pull the arm down on the wastegate control with realitive ease. I assume I am driving a diesel now not a turbo diesel. No boost guage to confirm. But the truck will start to bog down on hills when it should hold steady or pick up with boost. So.....

Can I use mechanics wire or a coat hanger or something and tie it so the arm coming from the wastegate control is fully extended and then go for a test drive as long as I watch the RPMs and keep them low as not to blow anything up?

I attached the new vacuum harness to a rubber hose that comes from what looks like the orginal vacuum pump instead of attaching it directly to the pump. That is where the broken harness was connected. Possible that that hose may have leaks in it letting vacuum escape?

Any ideas or thoughts especially any way I can temp. eliminate the vacuum operated wastegate to see if I can get the turbo to spool would be appreciated!

Thank you and ~GOD BLESS~

john

 

Without a boost gauge it is a bad idea to wire the wastegate shut for any reason.

Go buy a cheap vac/fuel pressure gauge at the parts store and use it for testing vacuum and boost and fuel pressure.

Then diagnose the problem with the vacuum-be it the vac pump or the wastegate solenoid?
Sometimes wd 40 sprayed into the vac ports on the wastegate solenoid will revive the solenoid.

A dead vac pump is not so easy.

 

You are right since I have no boost guage that is not a good idea. I'll leave it alone.

As for trying to revive the solenoid with a spray of WD40 that piece is a new ACX delco one. I'll check the line pressure right out of the vac pump instead of at the turbo.

Also I might try and see if I can get enough time to get the "connector" hose of the vac pump and run the harness directly to the pump incase that hose is rotted and leaking vacuum.

Thanks for bringing me back down to earth on the wiring idea!

~GOD BLESS~

john