C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

TPS and IAC problem

Thread Tools
 
Search this Thread
 
Old Jun 30, 2017 | 07:58 PM
  #1  
84grb's Avatar
84grb
Thread Starter
Cruising
 
Joined: Jun 2017
Posts: 12
Likes: 0
Default TPS and IAC problem

First off im new here and ive been a mustang guy for years..I bought a 84 vette with a few problems..Here is whats going on..Two main things i need help with..Neither of The IACs are functioning..I replaced one of them with a new AC Delco but made know difference..I set plunger to 1.125 but it doesnt move at all..Checked continuity between both IAC connecters and that was good..Question is do the IACs only work in series so if one is bad will that stop both from functioning.?..Second question is my TPS shows 3-4 volts all the time..I tried adjusting to .54 volts off two top wires but voltage will not budge..Any thoughts on this??

thanx in advance
Reply
Old Jul 2, 2017 | 02:46 PM
  #2  
Glassman89's Avatar
Glassman89
Instructor
20 Year Member
Liked
 
Joined: May 2002
Posts: 105
Likes: 1
From: Garland TX
Default

Your IAC problem is the IAC relays. They are located behind the battery. As the battery out gasses it destroys the relays. Trust me, I have been down this road. Good luck.
Reply
Old Jul 2, 2017 | 06:34 PM
  #3  
84grb's Avatar
84grb
Thread Starter
Cruising
 
Joined: Jun 2017
Posts: 12
Likes: 0
Default

Im having a problem finding anything list about iac relays and the only thing i come across behind my battery is a large connector i assume if for the dash..
thanx
Reply
Old Jul 3, 2017 | 03:03 AM
  #4  
Cliff Harris's Avatar
Cliff Harris
Race Director
15 Year Member
 
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Default

Originally Posted by 84grb
I set plunger to 1.125 but it doesnt move at all.
The ECM resets the IAC every time you turn on the ignition. You don't have to "set" it to anything. I always push the plunger in as far as it will go. The only thing to watch for is to not leave the plunger sticking out too far. If you do that the plunger guide will get broken when the IAC is screwed in.


Originally Posted by 84grb
Second question is my TPS shows 3-4 volts all the time..I tried adjusting to .54 volts off two top wires but voltage will not budge..Any thoughts on this??
That would happen if the ground is missing. That could be caused by a corroded connector pin or broken wire. Sometimes the wire breaks inside the insulation so you can't see. Use a volt/ohm/milliammeter to measure the wires to make sure they are making a connection.

Last edited by Cliff Harris; Jul 3, 2017 at 03:03 AM. Reason: Clarified wording.
Reply

Get notified of new replies

To TPS and IAC problem





All times are GMT -4. The time now is 02:05 PM.

story-0
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-1
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE
story-2
10 Things Every Corvette Owner Needs (2026 Edition)

Slideshow: 10 great gifts Corvette enthusiasts actually want for Father's Day!

By Michael S. Palmer | 2026-06-03 15:43:40


VIEW MORE
story-3
8 Most "Only Corvette Owners Understand" Quirks and Problems

Slideshow: These are the quirks, annoyances, and oddly lovable problems that every Corvette owner eventually learns to live with.

By Pouria Savadkouei | 2026-05-28 09:31:39


VIEW MORE
story-4
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

Slideshow: 10 reasons why the C6 Z06 is still a performance benchmark after 20 years.

By Joe Kucinski | 2026-05-27 17:20:09


VIEW MORE
story-5
How Much Horsepower Every Corvette Engine "LOST" in 1972

Slideshow: How much horsepower every Corvette engine lost in 1972.

By Joe Kucinski | 2026-05-27 16:54:53


VIEW MORE
story-6
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-7
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-8
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-9
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE