Cruise Control Issues
#1
Burning Brakes
Thread Starter
Cruise Control Issues
I have fixed all the vacuum leaks that I could find underneath the intake manifold. I replaced the 3 way check valve for cruise, but that seemed to not make a difference.
When I set a speed the car will constantly apply some throttle then let off, apply throttle, then let off. It repeats this cycle the entire time I have the cruise set. Is there a computer that controls the cruise? Could it be the stalk on the steering column?
I don't know what to look at. Any suggestions are appreciated.
When I set a speed the car will constantly apply some throttle then let off, apply throttle, then let off. It repeats this cycle the entire time I have the cruise set. Is there a computer that controls the cruise? Could it be the stalk on the steering column?
I don't know what to look at. Any suggestions are appreciated.
#4
Safety Car
Have you tried moving the hole the pin is set in to one where there is more give in the cable.
You could have it pulled tight leaving no room in the cable.
From the image on the net is shows many holes near the vacuum chamber move it from one to another.
The first adjustment hole, I would try would leave more slack in the cable.
You could have it pulled tight leaving no room in the cable.
From the image on the net is shows many holes near the vacuum chamber move it from one to another.
The first adjustment hole, I would try would leave more slack in the cable.
#5
Pro
Member Since: Jan 2004
Location: Chester SC
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St. Jude Donor '15-'16, '21
Bob has your fix. My CC responded exactly as yours. A while back when I adjusted my TB cable, I didn't get the pin back into the exact hole (or, my cable adjustment required another hole for the cruise).
#6
Burning Brakes
Thread Starter
#10
Burning Brakes
Thread Starter
From the earlier posts they make it sound like their cable was too tight. If I am understanding this correctly, it appears mine is on the loosest setting. Could it be too lose?
What I understand is this vacuum diaphragm actually moves in not out correct?
What I understand is this vacuum diaphragm actually moves in not out correct?
#11
Pro
Member Since: Jan 2004
Location: Chester SC
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St. Jude Donor '15-'16, '21
Billy, from the beginning, I was wondering about the comment that a Forum member's cable was tight. Mine was loose, like yours.
But both extremes can't be good!
Go ahead and move the cable to a tighter hole (please, no XXX comments!) and test your cruise control.
I have the Helms manual upstairs. I can't read up on the factory fix right now but will get back with you soon.
Happy New Year!
But both extremes can't be good!
Go ahead and move the cable to a tighter hole (please, no XXX comments!) and test your cruise control.
I have the Helms manual upstairs. I can't read up on the factory fix right now but will get back with you soon.
Happy New Year!
#12
Burning Brakes
Thread Starter
Digging up my old thread.
I tried moving the cable for the cruise control and it made 0 difference for how well the cruise worked.
What is the best way to troubleshoot this?
The issue is I can set the cruise and while driving it will open the throttle for a second then snap shut, it will repeat this process the entire time it is on. I can accerlate with the cruise no problem using the control stalk.
Any ideas?
I tried moving the cable for the cruise control and it made 0 difference for how well the cruise worked.
What is the best way to troubleshoot this?
The issue is I can set the cruise and while driving it will open the throttle for a second then snap shut, it will repeat this process the entire time it is on. I can accerlate with the cruise no problem using the control stalk.
Any ideas?
#16
Burning Brakes
Thread Starter
I would like to mention that both my AC and heat work just fine.
Last edited by billy mild; 03-09-2015 at 07:30 PM.
#18
Melting Slicks
Hi
It may be a bad connection in the cruise control stalk, cruise control stalk connector under dash or the dash as others have mentioned.
Have you tried the simple things like the cruise control vacuum switch at the brake pedal, try a simple adjustment each way and see.
However that just cuts the cruise control while going over a bump, it should not resume without your input.
Unplug the connector and reconnect, check the vacuum hoses for cracks. if the vacuum is intermittent due to cracked vacuum hoses that can explain your issues.
First thing you should buy once you have a corvette is the shop manual. See below.
http://www.ebay.com/itm/1991-Chevy-Corvette-OEM-Service-Shop-Manual-from-Dealership-/391039907608?hash=item5b0bcb7718
It may be a bad connection in the cruise control stalk, cruise control stalk connector under dash or the dash as others have mentioned.
Have you tried the simple things like the cruise control vacuum switch at the brake pedal, try a simple adjustment each way and see.
However that just cuts the cruise control while going over a bump, it should not resume without your input.
Unplug the connector and reconnect, check the vacuum hoses for cracks. if the vacuum is intermittent due to cracked vacuum hoses that can explain your issues.
First thing you should buy once you have a corvette is the shop manual. See below.
http://www.ebay.com/itm/1991-Chevy-Corvette-OEM-Service-Shop-Manual-from-Dealership-/391039907608?hash=item5b0bcb7718
#19
Race Director
Rent a vacuum (MightiVac) device from your local parts store and attach it to the rubber tube that leads from your brake pedal to the engine compartment. If it does not hold pressure then you simply need to find the leak.
My leak was a hole in the rubber line where it connects to the vacuum reserve ball (#16 in the diagram) that sits under the left headlight. I clipped off the last 1/4" and reattached it - fixed! Been a long time so I cannot remember whether it was on my old 91 or a previous C4.
Here is a diagram of the 85 and later cruise control system.
My leak was a hole in the rubber line where it connects to the vacuum reserve ball (#16 in the diagram) that sits under the left headlight. I clipped off the last 1/4" and reattached it - fixed! Been a long time so I cannot remember whether it was on my old 91 or a previous C4.
Here is a diagram of the 85 and later cruise control system.
#20
Burning Brakes
Thread Starter
I have a mityvac like device. I trued pulling vacuum on the lines and it held vacuum without issue.
My car doesn't lose cruise altogether it just pulsates kind of.
If I hold the cruise in the accelerate position it will accelerate without issue. It sounds like my staulk might be bad or the connection.
My car doesn't lose cruise altogether it just pulsates kind of.
If I hold the cruise in the accelerate position it will accelerate without issue. It sounds like my staulk might be bad or the connection.