Jon S
Well-known member
81I13 - NOV 80 - Idle Speed Control - Replacement Procedure;
82I144 - MAR 83 - Idle Speed Control Assembly - Repair Kit.
82I144 - MAR 83 - Idle Speed Control Assembly - Repair Kit.
Anyone Have Details on these TSBs for 1981 corvette?
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If you haven't already done so, check the Knowledgebase here under the Tech Center tab above.
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Peer81
Well-known member
I'm wondering what they mean with Idle speed control. As a 81 corvette doesn't have a idle speed control solenoid (In a rebuild manual I've seen later E4ME's do). Could it be the Idle rpm solenoid for the AC?
Greetings Peter
Greetings Peter
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Jon S
Well-known member
No clue Peter . . . the reason I'm asking is that my 100% original 1981 surged for the 3rd time in the past 8 years and someone suggested I research these TSBs. By "surged," the car was idling at 550 RPMs and while my foot was still on the brake, the engine suddenly soared to 5,000+ RPMs. Scarey, to say the least. I cut the ignition and upon re-start, the idle was back at 550 and the car performed perfectly normal. This is a totally intermittant problem, but has occurred 3x now. Twice in DRIVE and once in REVERSE. Scarey, to say the least!
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Jon,Here is the link to the service bulletins..
Once you open "This Link" you can browse by category.. It is not a complete listing but pretty close to being complete
Good luck
Bud
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Jon S
Well-known member
Bud -
Checked this link before posting. Thanks!
Jon
Checked this link before posting. Thanks!
Jon
Hib Halverson
Technical Writer for Internet & Print Media
My ESI only goes back to 1981 and that first document was issued in 1980, so I do not have a copy of it.
The second document covers a revised idle speed control for MY 81 and 82, however, it's said above that 81 Corvette did not use an ISC so it is possible this TSB doesn't apply.
If the engine has no ISC, I'd replace the HVAC idle solenoid
#82-I-144: POOR IDLE/(CODE 30 CAD. ONLY) ISC ASSEMBLY REPAIR KIT - (Jun 16, 1983)
Subject: IDLE SPEED CONTROL ASSEMBLY REPAIR KIT
A revised gear and shaft has been released for 1982 production idle speed control assemblies. Idle speed control assemblies with the new gear and shaft may be identified by a yellow dot on the housing near the shaft.
In order to provide these improvements to the service assemblies, two (2) separate service repair packages have been released to repair 1981 and 1982 idle speed control assemblies (ISC). Applications are as follows:
P/N Application -------- ---------------------------- 17079749 For Cavalier series equipped with engine Code "G"
17079750 All other engines
The repair kits contain a gear and shaft assembly, a boot, grease and an instruction sheet.
The repair packages are to be used if the following conditions exist:
o Idle speed control assembly runs forward and reverse, but plunger does not extend or retract properly.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
The second document covers a revised idle speed control for MY 81 and 82, however, it's said above that 81 Corvette did not use an ISC so it is possible this TSB doesn't apply.
If the engine has no ISC, I'd replace the HVAC idle solenoid
A revised gear and shaft has been released for 1982 production idle speed control assemblies. Idle speed control assemblies with the new gear and shaft may be identified by a yellow dot on the housing near the shaft.
In order to provide these improvements to the service assemblies, two (2) separate service repair packages have been released to repair 1981 and 1982 idle speed control assemblies (ISC). Applications are as follows:
P/N Application -------- ---------------------------- 17079749 For Cavalier series equipped with engine Code "G"
17079750 All other engines
The repair kits contain a gear and shaft assembly, a boot, grease and an instruction sheet.
The repair packages are to be used if the following conditions exist:
o Idle speed control assembly runs forward and reverse, but plunger does not extend or retract properly.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
Peer81
Well-known member
The way I look at it is this. What can make your engine turn open the airvalves in the carb to WOT (because that is what is happening I think).
Something like your foot, broken return springs on the carb etc etc. But the way it's happening I'm thinking about the cruise control. The cruise control is also controlling your carb and this problem is common on cars with a old cc, but the cc normally only goes to WOT when it is misfunctioning AND when the cc is applied! (so not on it's own). Maybe a idea to remove the link from the cc to your carb and see if it's still happening.
Greetings Peter
Something like your foot, broken return springs on the carb etc etc. But the way it's happening I'm thinking about the cruise control. The cruise control is also controlling your carb and this problem is common on cars with a old cc, but the cc normally only goes to WOT when it is misfunctioning AND when the cc is applied! (so not on it's own). Maybe a idea to remove the link from the cc to your carb and see if it's still happening.
Greetings Peter
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Jon S
Well-known member
The way I look at it is this. What can make your engine turn open the airvalves in the carb to WOT (because that is what is happening I think).
Something like your foot, broken return springs on the carb etc etc. But the way it's happening I'm thinking about the cruise control. The cruise control is also controlling your carb and this problem is common on cars with a old cc, but the cc normally only goes to WOT when it is misfunctioning AND when the cc is applied! (so not on it's own). Maybe a idea to remove the link from the cc to your carb and see if it's still happening.
Greetings Peter
That makes the most sense as the CC "could" force a WOT condition. Nothing else makes any sense; especially since my foot was on the brake (which should disengage the non-engaged CC anyway). This has only happened 3x in 29 years, but it only takes 1x to really scare you. I don't use the CC because it does not hold smoothly but rather feels like someone giving gas, letting up on the gas, and then re-applying the gas as it's set at say 55 MP. Makes your stomach uneasy.
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