Re: IML: 1973 Cruise Control Weirdness

[Brad Hogg <luxoliner@xxxxxxx>]

It almost sounds like the cruise is working backward.  It's like it is 
pulling the throttle closed in attempts to hold cruising speed rather than 
pulling it open as it should.  I'd concentrate on the linkage as you 
described.  Are you SURE it is connected properly?  Being connected as it 
was before means nothing as you had the issue before you swapped out the 
cruise unit.  Check with a FSM or another car to see that things are 
connected as they should be.

----- Original Message ----- 
From: "Jay King" <j_king@xxxxxxxxx>
To: <mailing-list@xxxxxxxxxxxxxxxx>
Sent: Monday, May 08, 2006 9:58 AM
Subject: IML: 1973 Cruise Control Weirdness


Hello, list,

I've been working on getting my '73 LeBaron ready for the 300-mile trip to 
my daughter's college graduation this coming weekend, and I encountered a 
strange cruise control malfunction not covered in the FSM.

First of all, the servo works--electrical, vacuum, everything. I was 
concerned that it might be marginal so I swapped it with a cruise control 
servo off a Fifth Avenue (slightly different housing, but identical 
mechanically) and got the exact same symptom. Swapping the actuator cable 
brought no joy either.

Here's the symptom: accelerate the car to cruising speed, turn on the 
control, and press the button to engage. As with all Mopars of this vintage, 
the cruise control takes three or four seconds to take effect, at which 
point the engine speed should increase to the set level and the driver can 
rest his right foot and smile. Not on my car! The engine speed falls to idle 
and the accelerator pedal becomes brick-hard. Disengaging the cruise control 
by turning it off or tapping the brake lets the accelerator return to normal 
operation. So the cruise control works but it does not function, if that 
makes sense.

When I take any car to a mechanic, I always describe the problem and any 
steps I have taken to solve it but refrain from diagnosing. That's his job, 
and it's possible I could give him information that would cause him to waste 
time because I'm not that much of a diagnostician. However, in this case, 
I'm sure the problem is in the throttle connection. The servo works as it 
should, the cable moves freely (I swapped a Fifth Avenue cable onto the 
LeBaron, just to be sure), and the control system (turn signal switch, brake 
interface) is doing what it's supposed to do, so I'm stumped.

Any advice or suggestions would be appreciated. Thanks in advance!

Jay King
Meridian, Mississippi
<a href=mailto:j_king@xxxxxxxxx>j_king@xxxxxxxxx</a>

Honey Gold 1973 Imperial LeBaron 4DHT
Sterling Silver 1981 Chrysler Imperial Coupe
Charcoal Gray 1985 Chrysler Fifth Avenue
Nightwatch Blue 1987 Chrysler Fifth Avenue



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