Go Back   Corvette Forum > C4 Corvettes, 1984 - 1996 > C4 Tech/Performance
Sign in using an external account
Register Forgot Password?
Register Search Today's Posts Mark Forums Read FAQ Vendor Directory
Search
C4 Tech/Performance
L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine Sponsored by
J&D Corvette

Welcome to Corvetteforum.com!
Welcome to Corvetteforum.com.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join Corvetteforum.com today!


Corvette Store
 
 
C7 Parts & Accessories
C6 Parts & Accessories
C5 Parts & Accessories
C4 Parts & Accessories
C3 Parts & Accessories
C2 Parts & Accessories
C1 Parts & Accessories
Wheels & Tires
Sponsored Ads
 
 
Vendor Directory
  
Reply
 
 
 
 
Thread Tools Search this Thread
Old 03-14-2008, 11:32 PM   #1
SamD
Junior Member
 
SamD's Avatar
 
Member Since: Oct 2007
Location: Hudson FL
Default 96 C4 P0400 EGR code halp !!

Hi all....

I own a 96 C4 with 130k on it and it likes to throw me a random P0400 code when the CES/SES light comes up.

Sometimes it is fine for 3 or 4 weeks at a time, I clear the code and other times it is once a week with no consistancy to the speed, RPMs, fuel type or otherwise.

My local wrench tells me it is most likely a dirty intake system, and suggested I run some Lucas in the fuel for a while. Now that Im on my 15th tank of fuel and 15th bottle of Lucas, I see no change.

The EGR valve is relatively new, as far as it's shinyness goes. I can also manually press and release the valve by hand with good return. The vaccum solenoid is opening and closing (bench tested) and the lines do not appear to be leaking.

Is there a step Im missing to diagnose this EGR Valve failure code?

Any assistance is appreciated.
SamD is offline   Reply With Quote
Old 03-22-2008, 09:57 PM   #2
G-Sting
CF Senior Member
 
G-Sting's Avatar
 
Member Since: Jun 2005
Location: LaUgH, mOrE!
Default

G-Sting is offline   Reply With Quote
Old 03-22-2008, 10:05 PM   #3
jsup
CF Senior Member
 
jsup's Avatar
 
Member Since: Oct 2004
Location: Bergen County, NJ Democrats, doing for the country what they did for Michigan
Default

Stupid question, but does the 96 even have an EGR? I thought they addressed that in the cam...am I wrong?
jsup is offline   Reply With Quote
Old 03-22-2008, 11:15 PM   #4
BAM92
CF Senior Member
 
BAM92's Avatar
 
Member Since: May 2003
Location: Houston Texas
Default

If you have an LT1, it is the egr valve on the back of the manifold. My 96 (TransAm) LT1 sent the same code 2 months ago. It was the egr valve.
BAM92 is offline   Reply With Quote
Old 03-23-2008, 09:22 AM   #5
IRAraid
CF Senior Member
 
IRAraid's Avatar
 
Member Since: Jun 2006
Location: Elkton MD
Default Egr

I had a high mileage Blazer that would throw a sporadic EGR code as you describe. It was caused by chunks of carbon getting stuck in the EGR pintle/orifice. Found ~1/16 to 1/4" sized chunks several times.
Cleaning it every few weeks was a pain - even more often if a long trip was involved. Tried blocking off the EGR with a piece of sheet metal and it threw a code instantly. A piece of stainless screen wire greatly extended the cleaning cycle but didn't eliminate the need for it. I suppose a new set of valve seals or guides or rings was really needed.
If you remove the EGR for inspection, look for carbon deposits.
Good luck.
IRAraid is offline   Reply With Quote
Old 03-25-2008, 08:48 PM   #6
G-Sting
CF Senior Member
 
G-Sting's Avatar
 
Member Since: Jun 2005
Location: LaUgH, mOrE!
Default

If you really think it's a dirty intake, you can try some Seafoam to clean it. Do a search on it on this forum. Good stuff.

I had the codes P0400 on my '96 LT1 with 62,000 miles recently and just replaced the EGR valve as well as the solenoid valve. Seems to work fine now. ... however, when I had the fuel rail cover off, I noticed a leaking fuel pressure regulator at idle! I replaced this also. Whew, I was thankful I noticed it!
G-Sting is offline   Reply With Quote
Old 04-02-2008, 10:55 PM   #7
SamD
Junior Member
 
SamD's Avatar
 
Member Since: Oct 2007
Location: Hudson FL
Default

Thanks for the comments.

Yes, the 96 LT1 definately has EGR, and when I got this vehivle recently it appears the EGR valve is relatively new. I havent had it off yet, but I think it is time to try looking for deposits in it.

The fuel rails are most likely in need of cleaning like you guys suggest - I will look into this, too.

Update as soon as I learn something. Thanks for the direction to head.
SamD is offline   Reply With Quote
Old 04-02-2008, 10:55 PM
 
Go Back   Corvette Forum > C4 Corvettes, 1984 - 1996 > C4 Tech/Performance
Reload this Page 96 C4 P0400 EGR code halp !!
 
 
 
Reply

Tags
1996, 96, c4, chevrolet, chevy, code, corveete, corvette, egr, lt1, p0400, performance, po400, system, trouble


Thread Tools Search this Thread
Search this Thread:

Click for Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
egr and maf codes pastamike C4 Tech/Performance 4 01-03-2014 12:12 AM
help with codes please pastamike C4 General Discussion 2 12-29-2013 06:13 PM
Strange EGR Delete method??? JMelton C4 Tech/Performance 5 06-13-2013 12:09 PM
Anyone use Lucas Injector cleaner? I did & got a P0327 C H Jims79 C5 General 3 05-02-2013 08:55 PM
Service Engine Soon LIght "Code P0400" ????? Rome856 C4 Tech/Performance 2 11-07-2002 04:12 PM


All times are GMT -4. The time now is 09:08 AM.


Emails & Password Backup