Sole-vac kicking on to really high idle

[SvenTomas]

I'm just getting to dialing in my new '84 Eagle Wagon.  It only has 63,000 miles on it, and everything works great.  It all appears to be in original condition as far as emmissions/vacuum, etc.  One funky thing though is that when I place the HVAC control on 'Mac A/C', the idle kicks up way way high.  If I unplug the electrical lead to the sole-vac it kicks back down to normal.

Under this condition, the voltage to that lead is full charging voltage of 13.7+ volts.  I understand that the sole-vac electric stage is activated when the a/c is turned on to keep the idle up, but this is ridiculous.  Has me doing neutral drops at the stop signs.

Anyhow, I've just got the lead un-plugged for now.  Here's my questions:

 - what sends the signal to the sole-vac?  the ecm?  What is it monitoring to know when to kick in?
 - is the signal that gets sent just a 'light switch', in-other-words on/off (0v/12v)??  Or should/could it send variable voltage depending on need?
 - perhaps I just need to turn the little adjuster screw on the end of the sole-vac?

Thanks in advance for any help you can offer.

Tom in WA

[SvenTomas]

Just kidding about the neutral drops.  I currently have the sole-vac electrical lead un-plugged.  If I were to plug it back in, and then turn the a/c on, and I didn't want to fight (with the brakes) the high idle the sole-vac creates when stopped, I would put it in neutral, and then have to drop into gear, squaking the tires when taking back off.

Amazingly, other than that one issue, the car runs amazingly well.  Most of me wants to rip all that crap out, and go with a 2150 (which I really like and am familiar with from working on my '72 Ford Highboy), but another part of me likes that the factory system is running well.  I ran into Portland in it yesterday and got 27mpg. 

I feel like I might even do a little better once I retune it.  It was bought in Denver originally best I can tell, and lived in Cheyenne, WY, so has the high altitude factory setup.  I live at 2,000ft. in Washington state, and will mostly run it from 2000 down to sea level.  So, I found the little jumper at the passenger's feet, and will retune this weekend when I replace my incredibly leaky valve cover with a new aluminum one.

Maybe I'll try to adjust the screw on the Sole-Vac.  Now that I think of it, my a/c is not charged right now . . . I wonder if that has anything to do with it.

[PR1AWRet]

Easiest instructions I have found on setting these carbs.

http://home.sprynet.com/~dale02/solvac.htm

[AMC of Houston]

The sol-vac is indeed adjustable.   You really should go thru and set everything per the AMC Service Note IS-12e.   Its a complete procedure to set everything timing- and carb-related.   It should be in the Nest archives somewhere; but I'd be happy to send you a scan if you PM me your email address.

[SvenTomas]

Thanks for the replies.   AMC of Houston, I just sent you an email requesting the scan of that IS-12e. Thanks.

So, I have deduced then that the electrical lead to the sol-vac is either on or off (0v or 12v)?? At first, I assumed that something was wrong and it should be receiving small doses of anywhere from 0v - 12v for varying levels of idle kick.  Seems like all I have is a mal-adjusted sol-vac.

I will wait for the IS bulletin and set all timing and idle speed accordingly.  This is good since I am now in lower elevation and this was factory set up for high elevation.

The only weird thing I have still, is that last night when I went to adjust the timing, the engine would stall when I removed the vacuum line from the distributor.  Seems like that shouldn't happen.  I also cannot seem to locate the 'vacuum switch' that the diagram says to remove the electrical lead from.

Where should the vacuum line from the front of the distributor go?

Thanks for all the great help.

[ammachine390]

Sol-vac has only 3 positions. Off, electric portion energized, and vacuum portion actuated. With the electrical solenoid portion, it either has no power at all or has battery voltage to it, no in between. The vacuum switch is located on the passenger side fender wall across from the distributor. It has a 3 wire connector and has 2 vacuum lines going to it.