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

Bad EGR Valve?

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Old Jun 29, 2015 | 10:15 AM
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Default Bad EGR Valve?

Hey Y'all. My SES light came on and I retrieved a H32 code. It looks like a vacuum or EGR issue. I looked at all of my vacuum lines and connections and I don't see any visible cracks or disconnected lines. They all appear to be in great shape. Is it worth it to just replace a $35 EGR valve before taking it into the mechanic?
When the SES light came on I didn't notice any change in performance, but I only drove it for about a mile afterward.

Any other ideas for tracking down a potential vacuum issue?

Thanks!
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Old Jun 29, 2015 | 07:38 PM
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Remove the vacuum line going into the EGR valve. Take a small drill bit and insert and turn it by hand into the EGR valve where the vacuum line attaches to the EGR valve. As you turn it into the opening, you may find it stops spinning. That means the vacuum line into the EGR is clogged up. Spin the drill bit by hand while applying pressure to push it into the opening. Once it clears the clog out, the drill bit will go far into the EGR valve. Remove the drill bit and install the vacuum line back onto the EGR valve. Disconnect the battery for a few minutes and then reconnect it. That should turn off the Check engine light. Problem may be solved!
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Old Jun 29, 2015 | 09:09 PM
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What year?
Could be an EGR temp switch too.
When does the code appear?
Does it go away after shutting down the engine?
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Old Jun 30, 2015 | 12:01 AM
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I've had to replace a couple of EGR valves over the years. Both failed due to the metal diaphragm cracking ( I believe). Semi easily tested with a Mityvac (hand pump) and an inspection mirror. Make sure you get the correct valve part as there a many different types (Neg / Pos) (beware Universal EGRs).
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Old Jun 30, 2015 | 12:24 AM
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Don't forget the EGR solenoid that applies vacuum to the EGR valve...
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Old Jun 30, 2015 | 12:06 PM
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Originally Posted by FOURSPEEDVETTE
Remove the vacuum line going into the EGR valve. Take a small drill bit and insert and turn it by hand into the EGR valve where the vacuum line attaches to the EGR valve. As you turn it into the opening, you may find it stops spinning. That means the vacuum line into the EGR is clogged up. Spin the drill bit by hand while applying pressure to push it into the opening. Once it clears the clog out, the drill bit will go far into the EGR valve. Remove the drill bit and install the vacuum line back onto the EGR valve. Disconnect the battery for a few minutes and then reconnect it. That should turn off the Check engine light. Problem may be solved!
Thanks!!!!!
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Old Jun 30, 2015 | 12:07 PM
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Originally Posted by JrRifleCoach
What year?
Could be an EGR temp switch too.
When does the code appear?
Does it go away after shutting down the engine?
It's a 1994. Yeah the code does go away most of the time.

THanks for your reply.

The code first appeared while cruising down the street at about 40 mph.
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Old Jun 30, 2015 | 12:08 PM
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I just tested the valve itself, and it's working. I guess I might have a vacuum leak then?
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Old Jul 1, 2015 | 12:03 AM
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See post #5.

My EGR solenoid failed and the EGR valve froze up and stopped working.
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