Troubleshooting '80 Monte Turbo

[shotwell]

OK guys, I'm back in town. Time to get this Monte running right. Thanks for all of your help in the previous thread, "Preparing for a cross country trip."

We left off thinking that the vacuum waste gate actuator wasn't working, causing an over boost condition. When I start the car, cold or warm, the waste gate doesn't move. Even when I rev it up to 4500RPM or so, nothing. I removed the actuator. Is there any specific way to test it? There are two vacuum ports on it. Also I noticed that the waste gate moves freely when not connected. It only moves about 1/4" from open to closed. Is this correct?

 

[Ttype83]

IT is working fine so far. You can put a vac gauge on it to see if it holds vac pressure. The back one is the boost side and the forward one is the vac side. This side will leak and is not needed.
To see if it moves under load you need two people. Put in drive foot on brake and get it to boost to around 3 psi. any thing more and the tire will spin. Have the person watch to see if it moves slightly (not from the front of the car unless you want to run them over )

If you are over boosting it could be one of three main things
1. vac lines leaks
2. cracked headers/ leaking exhuast..uppipe,crossover
3. HG blown
I would think the first two.

Jim

 

[shotwell]

Well, I put it back on and watched to see if the waste gate moved at all. It moved only a little, just barely enough to notice. Is that ok? (Also noticed that I need new motor mounts...are they easy?) I really have no idea if I am overboosting since I have no boost gauge yet. That was a hypothesis based on some pinging I was hearing at WOT. I didn't note any of that today. I connected a hand vacuum pump to the forward side of the actuator and it didn't hold any vacuum. Is it the back side that I am supposed to check? I don't seem to have any exhaust leaks and I haven't tested for vacuum leaks yet. I plan on using the Brake Cleaner method, spraying it places and see if the idle rises. What's next?

 

[shotwell]

Here's the link to the previous topic with all the background:

http://turbobuick.com/forums/showthread.php?s=&threadid=92425

 

[b4black]

The forward port almost never holds vacuum, but as Jim mentioned, it doesn't do anything on our cars. Just make sure you block off the vacuum port on the plenum that it was connected to. It's on top, midway between the carb and turbo. The backside should hold vacuum, but it's pressure you want to apply to see if the rod comes out.

You won't be able to see the wastegate move on the car. You need a good amount of boost to move it and it's hard to build that much boost without going WOT. A cheap pressure gauge will answer all your questions.


I HIGHLY recommend going with a driver side poly motor mount from HRpartsNstuff. It is about $80, but it keeps the motor is place. Otherwise it flops around and the DP hits the frame - false knock (which retards the timing). A stock mount will be fine on the passeneger side. Not to bad to change.