C4 General Discussion General C4 Corvette Discussion not covered in Tech

1985 Code 33

Thread Tools
 
Search this Thread
 
Old May 1, 2017 | 09:56 PM
  #1  
85vegasvette's Avatar
85vegasvette
Thread Starter
Racer
 
Joined: Oct 2013
Posts: 483
Likes: 19
From: las vegas nv
Default 1985 Code 33

Okay i am offically scratching my head, 1985 here, replaced the connector for the MAF, Just got a factory MAF, still throwing a code, it idles fine when cold, the when i accelerate it bogs and backfies , when it gets warm its fine, it did the sdame thing with my other MAF , also tried the 88 MAF switch that was horrible, Which i stil have if anybody needs, but i am offically stumped, found a couple bad vacum lines replaced....so now i am at my wits end...HELP
Reply
Old May 1, 2017 | 11:15 PM
  #2  
Tod Stiles's Avatar
Tod Stiles
Instructor
Supporting Lifetime
 
Joined: Dec 2016
Posts: 241
Likes: 77
From: Arlington VA
Default

Originally Posted by 85vegasvette
Okay i am offically scratching my head, 1985 here, replaced the connector for the MAF, Just got a factory MAF, still throwing a code, it idles fine when cold, the when i accelerate it bogs and backfies , when it gets warm its fine, it did the sdame thing with my other MAF , also tried the 88 MAF switch that was horrible, Which i stil have if anybody needs, but i am offically stumped, found a couple bad vacum lines replaced....so now i am at my wits end...HELP
Code 33 is MAF high (voltage) i.e., showing more air flowing then there is. Here are the trouble shooting charts. I'm not too keen on the last part of test three where you probe the MAF harness with a 12v light. I'd try to avoid that if possible.

I'm going to assume you have no other codes set and that you've cleared the ECM, restarted and have code 33 again. I'd check you're grounds and look over all your wiring for breaks or shorts before you go too far with this.
Attached Images   
Reply
Old May 2, 2017 | 02:50 AM
  #3  
Cliff Harris's Avatar
Cliff Harris
Race Director
15 Year Member
 
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Default

Code 33 is an open connection from the MAF to the ECM, most likely a broken wire or corroded connector pin. Basically, the voltage is going to 5 volts because of the pullup resistor inside the ECM.
Reply
Old May 3, 2017 | 12:15 PM
  #4  
junkyard_dog72's Avatar
junkyard_dog72
Burning Brakes
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Jan 2014
Posts: 881
Likes: 221
2023 C4 of the Year Finalist- Modified
2022 C4 of the Year Finalist - Modified
2021 C4 of the Year - Modified Finalist
C4 of Year Finalist (appearance mods) 2019
2016 C4 of the Year Finalist
Default

Tuning in, I have this same exact issue
Reply
Old May 3, 2017 | 09:41 PM
  #5  
85vegasvette's Avatar
85vegasvette
Thread Starter
Racer
 
Joined: Oct 2013
Posts: 483
Likes: 19
From: las vegas nv
Default

Originally Posted by junkyard_dog72
Tuning in, I have this same exact issue
o


Gonna look at the connector again maybe re solder the wires, ..but I'll folks then and see, all this from.changing an air filter. ..amazing
Reply
Old May 13, 2017 | 08:56 AM
  #6  
85vegasvette's Avatar
85vegasvette
Thread Starter
Racer
 
Joined: Oct 2013
Posts: 483
Likes: 19
From: las vegas nv
Default

Originally Posted by junkyard_dog72
Tuning in, I have this same exact issue
o


Gonna look at the connector again maybe re solder the wires, ..but I'll folks then and see, all this from.changing an air filter. ..amazing
Reply
Old May 14, 2017 | 07:06 PM
  #7  
gerardvg's Avatar
gerardvg
Safety Car
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Aug 2009
Posts: 3,751
Likes: 276
From: Melbourne, Victoria, Australia
Default

Originally Posted by 85vegasvette
Okay i am offically scratching my head, 1985 here, replaced the connector for the MAF, Just got a factory MAF, still throwing a code, it idles fine when cold, the when i accelerate it bogs and backfies , when it gets warm its fine, it did the sdame thing with my other MAF , also tried the 88 MAF switch that was horrible, Which i stil have if anybody needs, but i am offically stumped, found a couple bad vacum lines replaced....so now i am at my wits end...HELP
Hi here is the wiring diagram for the MAF to burn of module and ECM connections.





Last edited by gerardvg; May 14, 2017 at 07:08 PM.
Reply

Get notified of new replies

To 1985 Code 33





All times are GMT -4. The time now is 08:08 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