[DeTomaso] More cruise control issues
Christopher Kimball
chrisvkimball at msn.com
Fri Sep 11 02:31:13 EDT 2009
This evening I did what was suggested by the last tech with whom I spoke. First, I tried the sensitivity switches in all their different positions. The difference between high and low sensitivity was barely noticeable. Then I fashioned an extension arm on the throttle so the cruise control cable would have more travel and therefore more leverage to move the throttle. The technician thought this might help in a high-horsepower/low weight scenario.
The extension arm may have made a little difference, but the thing still cycles annoyingly. This weekend PNW is going on a weekend trip with some freeway driving, so I'll get a chance to see if it's bearable or not over longer time periods. If not, the next step is to find an oscilloscope and do the tests you recommended below.
Sincerely,
Chris
From: SOBill at aol.com
Date: Thu, 10 Sep 2009 00:58:04 -0400
Subject: Re: [DeTomaso] More cruise control issues
To: chrisvkimball at msn.com
Chris,
The number of pulses per mile is not really critical to a
cruise control. Whatever number of pulses being produced when you hit
the SET SPEED button, represents the number of pulses the cruise control will
try to maintain with the throttle. If the number of pulses drops below the SET
SPEED number of pulses, the car will accelerate. If the number of pulses goes
above the SET SPEED number of pulses, the car will slow down.
If the pulses are erratic, then you will have a
problem.
I would find someone with, best case, an oscilloscope so you can
see the VSS output from the sender. It should be a solid square wave directly
proportional to wheel speed. If no oscilloscope, see if you can find someone
with a multimeter which has a frequency measuring function. many
small, inexpensive multimeter have frequency function these days. Connect the
meter between VSS and ground. The frequency should be stable at a constant wheel
speed and increase with increasing wheel speed. This testing is dead easy on
jack stands.
Wish I was near enough to help.
Let me know what you find,
SOBill
Taylor
sobill at aol.com
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