EGR Valve
Thread Starter
3rd Gear
Joined: Apr 2014
Posts: 3
Likes: 0
From: Lakewood WA.
EGR Valve
I have an 85 C4 that would pulsate upon acceleration. I disconnected the EGR valve and it stopped. My question is can I leave it this way
and not have any problems, or do I need to replace it.
Thanks GB
and not have any problems, or do I need to replace it.
Thanks GB
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
It's odd that the EGR would effect accel as it's only called for after some time at stead spead with coolant temp >175 deg F.
If you want to leave it disconnected just install a 160 deg T-stat to avoid having the ECM call for EGR while cruzin the highway.
If you want to leave it disconnected just install a 160 deg T-stat to avoid having the ECM call for EGR while cruzin the highway.
Safety Car
Joined: Oct 2007
Posts: 4,426
Likes: 229
From: Pennsylvania
Try pulling the rubber hose off of the EGR valve. Then insert a drill bit sized the same inner diameter as the metal tube on the EGR valve that the rubber hose came off of. If it"s clogged up, the EGR valve won't work and the drill bit won't go in very far. In that case, drill into the metal tube until it goes all the way into the EGR valve clearing out the clogged passage into the EGR valve. I think about an inch or two if I remember correctly. Reinstall the rubber hose and see if the EGR valve now operates correctly. All this can be done with the EGR valve still attached to the engine by the way. I hope this helps your problem.
Last edited by FOURSPEEDVETTE; Jun 24, 2014 at 10:24 PM.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
You might have a positive pressure EGR valve instead of the negative pressure one that is supposed to be in there. There should be an "N" marked somewhere on the EGR valve (usually after the part number).
Thread Starter
3rd Gear
Joined: Apr 2014
Posts: 3
Likes: 0
From: Lakewood WA.
Try pulling the rubber hose off of the EGR valve. Then insert a drill bit sized the same inner diameter as the metal tube on the EGR valve that the rubber hose came off of. If it"s clogged up, the EGR valve won't work and the drill bit won't go in very far. In that case, drill into the metal tube until it goes all the way into the EGR valve clearing out the clogged passage into the EGR valve. I think about an inch or two if I remember correctly. Reinstall the rubber hose and see if the EGR valve now operates correctly. All this can be done with the EGR valve still attached to the engine by the way. I hope this helps your problem.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
See this article on positive pressure EGR valves (especially the "EGR PROBLEMS" section on the second page):
http://www.tomco-inc.com/Tech_Tips/ttt26.pdf
Check this article for more info on Corvette EGR valves:
http://tech.corvettecentral.com/2012...egr-diagnosis/
Last edited by Cliff Harris; Jun 26, 2014 at 01:53 AM.
Thread Starter
3rd Gear
Joined: Apr 2014
Posts: 3
Likes: 0
From: Lakewood WA.
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