LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

How to check if my EGR valve is bad?

Old Oct 13, 2003 | 03:56 PM
  #16  
JSK333's Avatar
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From: Cincinnati, OH, USA
I wanted to bring this back up to let you know that I checked my EGR valve again today.

I thought that maybe the diaphragm was missing, because no matter how hard I pushed on that inside silver metal part, it wouldn't move.

I soaked it down with brake cleaner, use compressed air in the passages (which brought some crud out), and then pressed again... and THUMP, it finally moved in! So it was just that caked up that it was frozen.

I did a quick vacuum check by pushing it in then putting a finger over the vacuum port, and the diaphragm stayed pushed in until I took my finger off, at which point it came back out.

I did a quick check with the engine running and the tip-in hesistation seems to be gone! I'll report back when I go for an actual drive.

But I wanted to let you guys know that this valve can get caked up. I had previously a year or two ago soaked it down with Sea Foam DeepCreep, and apparently not even that had freed it up!
Old Oct 13, 2003 | 05:12 PM
  #17  
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That is great news! Thanks for the tip. The EGR valve is on the back of the intake manifold. Then what are the two EGR looking devices on each header/manifold (1995 OBD-1) in addition to the EGR Valve in the back?

Should those move too? Which side should you press on? Again, these are the two additional EGR looking devices on the exhaust header/manifold, not the valve on the back of the intake.
Old Oct 13, 2003 | 05:23 PM
  #18  
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The thing on the front of the driver's side manifold is the AIR pump fitting.

The fitting on the rear of the passenger's side manifold is the EGR exhaust source pipe, that feeds the exhaust to the EGR passageway in the intake manifold.

Neither of them have the push test.
Old Oct 14, 2003 | 02:27 AM
  #19  
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I have Edelbrock TES exhaust headers. They have two fittings, one that rise on each side... those are the one's I'm talking about. It is a 1995 OBD-1. The two fittings look a lot like EGR fittings... round disks.
Old Oct 14, 2003 | 02:32 AM
  #20  
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Block it off and be done with it.

I'm glad I don't have to deal with any of that BS with Hooker LT's.
Old Oct 14, 2003 | 02:35 AM
  #21  
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NO kiddin'! Kalifornia sucks when it comes to conformity and smog laws. Keep the faith in Mo!
Old Oct 14, 2003 | 02:40 AM
  #22  
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Originally posted by Wild1
NO kiddin'! Kalifornia sucks when it comes to conformity and smog laws. Keep the faith in Mo!
Ouch, I didn't see you were from Cali. I wonder if an inspection station would really know if they were long tubes, especially FLP's since they have all the emissions hookups.
Old Oct 14, 2003 | 03:38 AM
  #23  
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Hmmmmm.........

Starting to wonder if this is my tip in to WOT hesitation cause.......Come to remember the car was throwing an EGR code before the H/C package, and the old EGR was reused.......

Time to replace or block off it sounds like.
Old Oct 14, 2003 | 09:53 AM
  #24  
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I've considered the block off but I'm just concerned about the smog *****. The long tubes can work but the O2s are farther back which mean the computer needs to be reprogrammed... which isn't a big deal really. I've had these on since 95 (original owner) and every time I bring it in for smog, they look all over for the CARB approval. Even for the CAI by SLP... they look for the CARB sticker. I finally had to stick an additional sticker on the radiator support and in the owner's manual.
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