Cruise control problem - 85 El Camino (LG4)
#1
Cruise control problem - 85 El Camino (LG4)
My cruise died a quick death. I replaced the vacuum servo with a rebuilt, but it tried to work then died again. It'll go close to full throttle, back off, then just disconnect. Also, my Torque converter wouldn't lock up at the normal speed.
This is the second rebuilt vacuum servo(first was back about 18 months ago).
Could this be a bad servo or could I be having other problems such as VSS, buffer, or the cruise module (brains) itself.
Many thanks!!!
This is the second rebuilt vacuum servo(first was back about 18 months ago).
Could this be a bad servo or could I be having other problems such as VSS, buffer, or the cruise module (brains) itself.
Many thanks!!!
#2
Supreme Member
Join Date: Jul 1999
Location: Tucson, AZ, USA
Posts: 1,335
Likes: 0
Received 2 Likes
on
2 Posts
Car: '92 Z28; Dk Teal; Her Pkg
Engine: 305
Transmission: Richmond 6 Spd
Axle/Gears: Moser 9", Detroit Locker, 3.70
Check the brake pedal operated switches - they control cruise unlock, TCC power, in adition to the brake lights.
Tim
Tim
#3
Thanks for the quick reply, Tim.
Yes, the brake pedal switches are good. My SES is not setting any codes, i.e., no Code 24.
Because of this can I assume my VSS and buffer are good? Is there a way to test the cruise control module, then the vacuum servo?
Thanks!
Yes, the brake pedal switches are good. My SES is not setting any codes, i.e., no Code 24.
Because of this can I assume my VSS and buffer are good? Is there a way to test the cruise control module, then the vacuum servo?
Thanks!
#4
Supreme Member
Join Date: Jul 1999
Location: Tucson, AZ, USA
Posts: 1,335
Likes: 0
Received 2 Likes
on
2 Posts
Car: '92 Z28; Dk Teal; Her Pkg
Engine: 305
Transmission: Richmond 6 Spd
Axle/Gears: Moser 9", Detroit Locker, 3.70
Is the vacuum check valve between the manifold & the vacuum reservoir functional? Is the vacuum release valve, or the hose connecting it to the servo leaking when the brake is not depressed? In other words, will the reservoir hold a vacuum for quite some time, after the engine is shut off?
If the vacuum supply is OK, start by checking all of the inputs from the control switchs & the speed buffer (power, ground, set, accel, brake detect, speed buffer input) at the cruise module - make sure thay are not intermittant. The speed buffer may have two separate outputs - one for the ECM & speedo & another for the cruise module.
Tim
If the vacuum supply is OK, start by checking all of the inputs from the control switchs & the speed buffer (power, ground, set, accel, brake detect, speed buffer input) at the cruise module - make sure thay are not intermittant. The speed buffer may have two separate outputs - one for the ECM & speedo & another for the cruise module.
Tim
Thread
Thread Starter
Forum
Replies
Last Post
Ghettobird52
Tech / General Engine
15
12-29-2023 08:23 AM
eightsixseven
Tech / General Engine
1
08-14-2015 03:09 PM
Street Lethal
Engine/Drivetrain/Suspension Parts for Sale
3
08-13-2015 08:28 PM