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Old 01-20-2013, 08:13 AM   #1
Steve's 77
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1977 L82 Right bank running hot and rough idle - EGR issue?

Looking for feedback on a 77 L82 with 68,000 miles. Recently rebuilt the carb, new plugs and wires, timing is 14 degrees, new vacuum lines and runs MUCH better!!! Wow!!! The engine is still idling rough though in park and in drive (smoother under load) and the right bank (EGR Valve side) is running hotter than the left. Could this be an EGR valve issue? The EGR valve does not appear to hold a vacuum when I put the tester on it but, I am not sure if the actual valve should hold the vacuum or is it simply activated by the vacuum supplied by the vacuum line? Could my EGR valve be bad? Thanks
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Old 01-21-2013, 12:14 PM   #2
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The valve itself may be bad...but I suspect a vacuum leak.

Have you sprayed brake cleaner to see if the idle changes?

Once the engine is not, lightly start spraying brake cleaner to get a reaction. Try the carb first just to set your baseline of what you're looking for.

Then the base and body of the carb. Around the edges of the intake...particularly on the passenger side. See if the RPMs rise and if they do...you found a leak.
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Old 01-22-2013, 08:59 PM   #3
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1977 L82 Right bank running hot and rough idle - EGR issue?

Thanks! Good suggestions I will give it a try. I am also wondering how much a stretched timing change could contribute to this? Only 68,000 miles so I don't think it is the issue.
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Old 01-23-2013, 12:08 AM   #4
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Quote:
Originally Posted by Steve's 77 View Post
The EGR valve does not appear to hold a vacuum when I put the tester on it but, I am not sure if the actual valve should hold the vacuum or is it simply activated by the vacuum supplied by the vacuum line? Could my EGR valve be bad? Thanks

Since the garage was still heated from working on the vette earlier today, I wandered out and connected my hand vac pump to my EGR. (1979 L82). It holds vacuum. That might be your vacuum leak.
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Old 01-23-2013, 11:48 AM   #5
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1977 L82 Right bank running hot and rough idle - EGR issue?

Great!! Thank you, I appreciate the feedback. I am about to order a new EGR. Mine definitely does not hold vacuum. Once I have it and put it on I will update the post incase others have this problem. Thanks
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