81 monte carlo, turbo not working

[TheViper]

i have an 81 monte carlo with a buick v6 turbo in it from the factory. the boost wont go above 1.5psi. i'm not sure what the problem is exactly but i think it might be the vacume lines. what could it be?

 

[b4black]

1981 WASTEGATE ACTUATOR - For 1981, Buick changed the wastegate actuator from a normally closed design, to a normally open design. It was an attempt to improve fuel economy that was quickly abandoned in 1982 in favor of increased performance. (The NC design has more precise boost control.) The 1981 unit can be identified by the use of only one vacuum hose (instead of two). To accommodate this change, the wastegate lever on the elbow was rotated 180 degrees. A conversion is as simple replacing '81's actuator and elbow with '82/'83 units. If the turbocharger has been replace, this may have already been done.

The one vacuum line should go from the actuator to the plenum. Pull it and apply vacuum to the actuator. See if it leaks. Make sure it sucks the wastegate closed. If it does, check the other end for good vacuum (~15 psig).

When the actuator leaks on an '81, then there no boost, no power.

 

[TheViper]

i'l check it the way you say but the arm on the top of the turbo which is for the wastegate right? when you give it gas it moves. does this indicate the acuator is working?

 

[b4black]

Maybe.

At idle there should be plenty of vacuum to suck it closed. Only when vacuum drops, it will open. Reving it in park might lower vacuum enough to let it open. But if it's leaking, if would open too early.

Is the rod on the actautor adjustable? Can it be made longer/shorter?

 

[TheViper]

in park it opens if you give it almost 1/4 throttle. is this too early?

how much should the boost go up to when its working right?

 

[b4black]

Way too early I would think- never actually ran an '81 wastegate. But I do have one and I just looked at how it operates.

At idle there should be plenty of vacuum to suck it closed. Only when vacuum drops, it will open

This was wrong, sorry. The "NORMAL" refers to engine on/high vacuum. (I thought normal would be engine off as well, like non-'81's turbo's)

Engine off - no vacuum - rod fully out- WG shut
Engine on idleing - high vacuum - rod shortened - wastegate open
As rpm's increase - vacuum decreases - rod goes back out - WG closes - boost goes up
(I not sure what limits the boost then - at WOT there's no vacuum - no vacuum means WG closed )


Let's confrim you still have a '81 normally open wastegate. If you do, the rod will connect the wastegate hinge to the rear of the fulcrum or pivot point. All others connect toward the front of the fulcrum. Before you start the car, it should be long (and closed). As soon as you start the car, it will suck short (and open).

A healthy turbo will put out 9psi max form the factory. The normally open WG must add a lot of lag. That's why it only lasted one year.

 

[TheViper]

there must be a vacume leak somewhere i guess. it idles pretty high and it you try to slow it down it will run real rough and die.
the vacume on the boost guage only goes down to about 5, shouldn't it go to about 13-15? i'm probably going to have to have someone look at it and try to sort it out. i just don't know much about turbos.

 

[b4black]

I pull at least 15"Hg vacuum at idle. Maybe this will help. It's the vacuum diagram for a '81 Turbo V6:
http://www.flash.net/~rjgeorge/images/vac81a.jpg

 

[turbomontecarlo]

another one!!!

o crap!!! another 81 turbo monte carlo!!!! i didnt think i would ever find another person with one besides me and Roger!!!! wow !!! hey i have a bit of infor and links for that car if interested..... by the way...got any pictures?

 

[TheViper]

that diagram if great, that what i've been looking for. thx

info would be great if you have links and stuff. the car needs a lot of work, we got it for $250. i'l try to get some pics, my dad just left with the digital camera.