EGR question.
Thread Starter
Intermediate
Joined: Oct 2017
Posts: 26
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EGR question.
I have a 1991 corvette that started running rough, ive replaced everything almost except the egr and i was wondering if i unplugged the egr solenoid and plugged the egr valve, should it run right if that was the problem?
Race Director
Joined: Feb 2003
Posts: 16,475
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From: Kingman AZ
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Check the section of the FSM (Field Service Manual) that deals with this problem. Then follow the recommended steps to find the problem. You can purchase the CD of the manual that is specific to your 91 on line.
Diagnose first and do no just throw parts at it.
Diagnose first and do no just throw parts at it.
Melting Slicks
Joined: Jan 2014
Posts: 2,192
Likes: 381
From: Lunenburg MA
The EGR is only active at steady speeds under light throttle. It is possible for the valve to stick open, but pretty rare. You can make a block off plate for the EGR pipe flange if you want to rule it out.
It's more likely to be something else. Best to get something that can read the engine running parameters from the ODB port so you can see what's happening. Otherwise you're just guessing.
It's more likely to be something else. Best to get something that can read the engine running parameters from the ODB port so you can see what's happening. Otherwise you're just guessing.
Thread Starter
Intermediate
Joined: Oct 2017
Posts: 26
Likes: 0
Thanks, yeah i dont think an egr would make me stall and miss like its doing, ive taken it to 3 different mechanics but they all just dont put much thought into it before telling me to replace this or that. You guys have any clue? It runs good when you stomp on it but like to idle rough and miss at low speeds. Ive replaced injectors map, iac, tps, fuel pump, filters, distributor, plugs, wires, fuel pressure regulator, seriously what else could it be lol. Btw ive done this all over a period of time for individual problems.
Advanced
Joined: Oct 2019
Posts: 55
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Guys I bet you there is a bad ground somewhere. I have had the same problem, and scratched my head for a year til I accidentally found it. After adding all those new parts, it sure ran good when I cleaned off a ground wire to the firewall, and tightened it up.
Thread Starter
Intermediate
Joined: Oct 2017
Posts: 26
Likes: 0
this sounds like your on to something, can you point me in a direction to start checking?
Advanced
Joined: Oct 2019
Posts: 55
Likes: 12
Its not easy looking for shorts or bad grounds. Mine was simply the ground at the firewall behind the distributor. You may have to look in the FSM to find all the connections. You should use a multimeter to check voltages. I found mine by luck, but I'll bet there are guys on this forum who know this better than I. Good luck.
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