[DeTomaso] More cruise control issues

[Christopher Kimball]

The unit SOBill is letting me try is new.  I'm going to run the test he suggests to ensure it's working properly.  It may be the signal is weak, even with the step-up resistor I'm using, but we'll see.

Thanks,

Chris


From: cdifani at comcast.net
To: chrisvkimball at msn.com; sobill at aol.com; detomaso at realbig.com
Subject: Re: [DeTomaso] More cruise control issues
Date: Fri, 11 Sep 2009 02:29:32 -0700










Chris:
 
I guess the other question to ask here, is the VSS 
you got from SOBill "good"?  Was it in service in a working correctly 
cruise control?  Or did it come to you "new"?  I'm wondering if that 
might be the source of the surging?  If it's bad "out of the box failure", 
then you might want to try another one...  I've got one myself, but it's 
the kind that's designed for an electronic speedometer only.  It's only got 
3 wires coming out of it, ground, 12V+, and signal.  You're welcome to try 
it, but I can't say it's perfect... (because I'm not "on the road" 
yet).
 
Just a thought....
 
Chris
 
Chris Difani
'73 L #5829 "LITNNG"
The Electric Pantera
Sacramento, CA
Email: cdifani at comcast.net 
 



 
----- Original Message ----- 
From: "Christopher Kimball" <chrisvkimball at msn.com>
To: <sobill at aol.com>; "Pantera List 
Serve" <detomaso at realbig.com>
Sent: Thursday, September 10, 2009 11:31 
PM
Subject: Re: [DeTomaso] More cruise control 
issues

> 
> 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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