Installed headers, dropped AIR system = code (help!)
Thread Starter
Drifting
Joined: May 2007
Posts: 1,426
Likes: 165
From: Motor City
Installed headers, dropped AIR system = code (help!)
1993 LT1.
So, I installed a set of long tube headers over the weekend and they do not have the AIR pipe fittings.
I pulled the pump located in the drivers fender, the hose from the pump to the bypass valve, the valve itself and the hose from the valve to the metal air tubes on each manifold. There is one vacuum line on the bypass valve going to the intake manifold and an electrical connection. It was my understanding that everything running from the air pump was fair game to pull out.
Well, I got around to starting the car up and it has a "check engine light".
Pulled the code and I get H26. 'H' obviously meaning history, but the 26 refers to this:
Code #26: Quad-Driver Module #1 Circuit.
I was under the assumption on an OBD 1 car I would not throw a code.
Any ideas?
**updated with pictures
So, I installed a set of long tube headers over the weekend and they do not have the AIR pipe fittings.
I pulled the pump located in the drivers fender, the hose from the pump to the bypass valve, the valve itself and the hose from the valve to the metal air tubes on each manifold. There is one vacuum line on the bypass valve going to the intake manifold and an electrical connection. It was my understanding that everything running from the air pump was fair game to pull out.
Well, I got around to starting the car up and it has a "check engine light".
Pulled the code and I get H26. 'H' obviously meaning history, but the 26 refers to this:
Code #26: Quad-Driver Module #1 Circuit.
I was under the assumption on an OBD 1 car I would not throw a code.
Any ideas?
**updated with pictures
Last edited by 9T3VETTE; May 9, 2011 at 10:07 PM.
Thread Starter
Drifting
Joined: May 2007
Posts: 1,426
Likes: 165
From: Motor City
Well I reset the ECM, i'll see if the code comes back when it's taken to the exhaust shop. Until then, here are some pics
The AIR system taken out
Close up
Vacuum line from bypass valve to manifold caped off
The AIR system taken out
Close up
Vacuum line from bypass valve to manifold caped off
Last edited by 9T3VETTE; May 9, 2011 at 10:11 PM.
Safety Car
Joined: Nov 2008
Posts: 4,328
Likes: 15
From: Jacksonville FL
Did the headers come with the O2 bung? If not you will need to buy a bung and have it welded in and install the sensor. I have read that sometimes a heated O2 is necessary as well. Hopefully someone will provide more info on this or say I am fullofcrap, lol.
Good luck!
Good luck!
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
An O2 sensor will still be needed. A heated sensor "tricks" the ECM into going into closed loop a lot quicker. Adding the stock O2 sensor on the collector or reducer works, it just takes longer for the sensor to get hot.
Thread Starter
Drifting
Joined: May 2007
Posts: 1,426
Likes: 165
From: Motor City
It was my impression that the car would only get a check engine light if it was an OBDII car with the emissions delete, but not on an OBDI?
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
Yes, the car has o2 bungs and new sensors in the long tubes. I would have a whole list of other codes and problems if those were not installed
The EGR was not deleted, only the secondary AIR system (see pictures).
It was my impression that the car would only get a check engine light if it was an OBDII car with the emissions delete, but not on an OBDI?
The EGR was not deleted, only the secondary AIR system (see pictures).
It was my impression that the car would only get a check engine light if it was an OBDII car with the emissions delete, but not on an OBDI?
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Thread Starter
Drifting
Joined: May 2007
Posts: 1,426
Likes: 165
From: Motor City
Awesome.
Thanks for the help, guess it will have to be programed out.
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
I remember when I put my headers on, with the pump disconnected, it set a code. And if you plug the electrical connector into the pump it would not. But that pump running, without piping, sounds like a shop vac under the hood.
I ended up plumbing mine in, I needed it for emissions inspection anyways.
I ended up plumbing mine in, I needed it for emissions inspection anyways.
Thread Starter
Drifting
Joined: May 2007
Posts: 1,426
Likes: 165
From: Motor City
I remember when I put my headers on, with the pump disconnected, it set a code. And if you plug the electrical connector into the pump it would not. But that pump running, without piping, sounds like a shop vac under the hood. I ended up plumbing mine in, I needed it for emissions inspection anyways.
I ended up plumbing mine in, I needed it for emissions inspection anyways.
Advanced
Joined: Jul 2010
Posts: 59
Likes: 0
From: Bolingbrook IL
it must be the connection on the pump. I wonder if there is a way to fool it
Rick - '92 LT1
Le Mans Master
Joined: Mar 2001
Posts: 7,999
Likes: 14
From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
Cruise-In III Veteran
Cruise-In IV Veteran
St. Jude Donor '12
I took my old manifolds to the exhaust shop and had them remove the AIR tubes when I put on my long tubes with provisions for the tubes.
When I put in the 383 I had AIR & EGR removed and programmed out of the tune.
When I put in the 383 I had AIR & EGR removed and programmed out of the tune.
Thread Starter
Drifting
Joined: May 2007
Posts: 1,426
Likes: 165
From: Motor City
Try this.... put only the air pump itself back on, and plug it in. See if that keeps the the SES light off. Then you know you'll need a resistor to fool the ECM. I think it only looks for a voltage drop at the pump to be sure it's working. There isn't any 'sensor' that detects actual air flow.
Rick - '92 LT1
Rick - '92 LT1
Thread Starter
Drifting
Joined: May 2007
Posts: 1,426
Likes: 165
From: Motor City
Update:
Well I ended up putting the pump back in along with the bypass valve, and plugged both in.
In order to reduce the noise I pulled the front cover off the pump and pulled the fan blade out. Put the cover back on with 8 or so screws, and it's very quiet when operating.
Until I get a tune, this will do. Thanks for the help.
Well I ended up putting the pump back in along with the bypass valve, and plugged both in.
In order to reduce the noise I pulled the front cover off the pump and pulled the fan blade out. Put the cover back on with 8 or so screws, and it's very quiet when operating.
Until I get a tune, this will do. Thanks for the help.
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
Your code is not related to the secondary air system. A quad driver module is in the ECM and drives injectors I believe.