Working cruise control
03-03-2006, 03:42 PM
#1
Rennlist Member
Thread Starter
Working cruise control
My cruise had stopped working, it would set but not hold and the car would slow. It seemed to be vacuum, but wasn't. On John Pirtle's site is great info regarding cruise control trouble shooting and fixing. The controller had a couple of circuits that needed to be resoldered. The gentlemen at Creative Custom Choppers (they did the SC install) did the actual work; seems to be OK now.
03-03-2006, 04:24 PM
#3
Rennlist Member
Thread Starter
http://members.rennlist.com/pirtle/z0_keep_main.html
http://members.rennlist.com/pirtle/z...se_control.txt
The first is John's site the second is the link to CC
http://members.rennlist.com/pirtle/z...se_control.txt
The first is John's site the second is the link to CC
03-03-2006, 04:28 PM
#4
Nordschleife Master
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Hmm... I might have to look into this... but I kinda like the cruise control switch being the instant accelleration switch. I think it pushes the throttle open more than my foot can, although that may just be puckering distortion in the assometer.
If you ever need to find pirtle's or nichol's site just type their name and 928 in google. First result every time.
http://members.rennlist.com/pirtle/
If you ever need to find pirtle's or nichol's site just type their name and 928 in google. First result every time.
http://members.rennlist.com/pirtle/
03-03-2006, 10:01 PM
#6
Rennlist Member
Originally Posted by nee.dragger
Anybody done this procedure with pictures to illustrate?
03-04-2006, 11:02 AM
#7
Rennlist Member
SharkSkin wrote:
"Not much to it -- pull the box apart, clean the gunk off the bottom where all the solder joints are, and resolder all of them. Be careful not to overheat any components! My writeup is near the middle of this page."
Great write-up and pix, Dave. Thanks.
I have a couple of questions:
"...I cleaned all of the varnish protectant off of the solder side of the PCB..."
Please comment on how you did this, what solvent, what not to do and so forth, and why it's important. Did you re-varnish? Is that important?
"... and resoldered every lead on the board, ..."
Please comment on technique and wattage of iron, etc. I wasn't an electronic hobby kid. Do you have an opinion on that CoolHeat instant soldering iron?
"Not much to it -- pull the box apart, clean the gunk off the bottom where all the solder joints are, and resolder all of them. Be careful not to overheat any components! My writeup is near the middle of this page."
Great write-up and pix, Dave. Thanks.
I have a couple of questions:
"...I cleaned all of the varnish protectant off of the solder side of the PCB..."
Please comment on how you did this, what solvent, what not to do and so forth, and why it's important. Did you re-varnish? Is that important?
"... and resoldered every lead on the board, ..."
Please comment on technique and wattage of iron, etc. I wasn't an electronic hobby kid. Do you have an opinion on that CoolHeat instant soldering iron?
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03-04-2006, 11:18 AM
#8
Burning Brakes
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Yeah Fogey....DON"T even consider a "Cold-Heat" soldering tool. (JUNK)...Go to Radio Shack, or WalMart, and get a Pencil soldering iron, 25 watts or so will be fine...Get some thin Rosin core solder, some DeSoldering wire, and do a little reading on soldering circuit board technique....Even better, if you have an old transistor radio, or broken TV or something...do some "Hands-on" practice. You'll have the hang of removing the old solder, and resoldering the joint in no time...Then...tackle you CC board... 
Or ask Rich or Alan to repair it for you...I am sure either one of them would be able and willinig to have a look at it for you...
Or ask Rich or Alan to repair it for you...I am sure either one of them would be able and willinig to have a look at it for you...
03-04-2006, 01:52 PM
#10
Rennlist Member
Will, Berryman's B-12 took the coating right off. Just be careful to only get it on the solder side of the circuit board, as it could do some damage to components on the other side. Avoid getting it on the plastic connector. It could also remove the markings from some components, making it harder to troubleshoot/fix, though that doesn't strike me as something you'd be likely to undertake yourself anyway.
A basic soldering iron as Jeff mentioned will do the job fine; get one with a grounded tip to be safe. Also, I did not remove any old solder except in a couple places where there was too much. Use solder braid for that, you can throw solder-removal tools that use suction in the trash with the Cold-Heat soldering tool. I'm just old school I guess, I would consider the Cold-Heat tool to be for emergencies only and would never rely on that alone. I basically re-flowed each joint, putting just a touch of new solder on each -- more to get the flux than to get the solder. Use the thin ~0.032 dia. rosin core. R.S. might have some info booklets on soldering. The key IMHO is to be able to re-solder each joint quickly and cleanly. You want to be done with each joint before the heat gets to the component. Strangely, a 30-watt iron will help you acheive this easier than a 15-watt iron. I agree that finding a junk circuit board to practice on is a good idea.
A basic soldering iron as Jeff mentioned will do the job fine; get one with a grounded tip to be safe. Also, I did not remove any old solder except in a couple places where there was too much. Use solder braid for that, you can throw solder-removal tools that use suction in the trash with the Cold-Heat soldering tool. I'm just old school I guess, I would consider the Cold-Heat tool to be for emergencies only and would never rely on that alone. I basically re-flowed each joint, putting just a touch of new solder on each -- more to get the flux than to get the solder. Use the thin ~0.032 dia. rosin core. R.S. might have some info booklets on soldering. The key IMHO is to be able to re-solder each joint quickly and cleanly. You want to be done with each joint before the heat gets to the component. Strangely, a 30-watt iron will help you acheive this easier than a 15-watt iron. I agree that finding a junk circuit board to practice on is a good idea.
03-04-2006, 02:06 PM
#11
Why potentially damage a good cruise control when it may not be the problem?
For those that want a reliable and lasting solution, call 928 Int'l as they stock
rebuilt units, i.e. and other rebuilt parts, at reasonable prices.
A damaged cruise control unit may result in two cruise control system problems
which further complicates a system diagnosis.
For those that want a reliable and lasting solution, call 928 Int'l as they stock
rebuilt units, i.e. and other rebuilt parts, at reasonable prices.
A damaged cruise control unit may result in two cruise control system problems
which further complicates a system diagnosis.
03-04-2006, 02:21 PM
#12
Rennlist Member
Loren, I mentioned in my writeup that I went through the diagnostics in the WSM. It was very easy to follow, and in my case I made it to the last line which says basically "replace cruise brain". At that point it is a zero risk proposition.
03-05-2006, 12:30 PM
#13
Rennlist Member
SharkSkin wrote:
"Will, Berryman's B-12 took the coating right off. ... etc"
Thanks, Dave, that was very helpful.
I googled "how to solder" yesterday and came up with a few useful links. (Included here for other hopeless ignorami like me.) Inter alia:
http://radiojove.gsfc.nasa.gov/elab/soldering.htm
From NASA, no less, with useful movies.
"Will, Berryman's B-12 took the coating right off. ... etc"
Thanks, Dave, that was very helpful.
I googled "how to solder" yesterday and came up with a few useful links. (Included here for other hopeless ignorami like me.) Inter alia:
http://radiojove.gsfc.nasa.gov/elab/soldering.htm
From NASA, no less, with useful movies.
03-05-2006, 02:03 PM
#14
4th Gear
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Cruise control diagnostics:
I'm trying to diagnose the trouble with my cruise control. ('87 S4 Auto UK)
At first I thought it was too much play in the bowden cable - tightened so there is about 1-2mm of slack - no effect.
So then I thought - ahh it's probably vacuum - so I'm waiting for my new Mityvac to arrive on Tuesday.
But - I thought - I might as well have a go at the electrical diagnosis in the meantime and
The results are WIERD!
With the ignition on and engine not running.
between terminals 5 and 12 I'm getting about 8.5 volts instead of battery voltage.
Between terminals 6 and 12 that is supposed to be 0 volts until the brake is pressed is showing around 8.5 volts all the time.
Terminals 8,9,10 don't seem to be getting the switch inputs from the cruise control lever.
I have checked the lever and the switch is working.
Any ideas anyone?
Bruce
'87 S4 Auto UK - Lagoon Green
I'm trying to diagnose the trouble with my cruise control. ('87 S4 Auto UK)
At first I thought it was too much play in the bowden cable - tightened so there is about 1-2mm of slack - no effect.
So then I thought - ahh it's probably vacuum - so I'm waiting for my new Mityvac to arrive on Tuesday.
But - I thought - I might as well have a go at the electrical diagnosis in the meantime and
The results are WIERD!
With the ignition on and engine not running.
between terminals 5 and 12 I'm getting about 8.5 volts instead of battery voltage.
Between terminals 6 and 12 that is supposed to be 0 volts until the brake is pressed is showing around 8.5 volts all the time.
Terminals 8,9,10 don't seem to be getting the switch inputs from the cruise control lever.
I have checked the lever and the switch is working.
Any ideas anyone?
Bruce
'87 S4 Auto UK - Lagoon Green
03-05-2006, 02:23 PM
#15
Banned
[QUOTE=Mark]
Can't beleive I wasted my time with it
The little tip breaks off and its hard to get it to "heat" up and its not instant off, I can burn a hole through my hand if i want.
Originally Posted by jeff jackson
....DON"T even consider a "Cold-Heat" soldering tool. (JUNK)...QUOTE]
AMEN! WHATTAPIECEOF****!
AMEN! WHATTAPIECEOF****!
Can't beleive I wasted my time with itThe little tip breaks off and its hard to get it to "heat" up and its not instant off, I can burn a hole through my hand if i want.