C3 Vacuum diagnosis
Instructor
Joined: Jul 2021
Posts: 148
Likes: 107
From: Boston
Following along! I also have an 82 with Crossfire that I just bought. 9300 original miles.
My car also will idle at 2000rpm and eventually come down to maybe 1200 or so, but that's about as low at it will get.
I have an audible vacuum leak inside the passenger compartment.
The air intake hood flapper vacuum line is disconnected....
The car came with a partially used intake gasket set. Just the throttle body gaskets were used from the kit. I'm sure I'll find a surprise in there too..
Unfortunately the car is in winter storage, so no work can be done on it. So, I've armed myself with the GM assembly manual and the shop manual as well..
Crossfire was produced for 3 model years, more than 35 years ago. Most techs now-a-days weren't even alive when Crossfire was introduced.
My car also will idle at 2000rpm and eventually come down to maybe 1200 or so, but that's about as low at it will get.
I have an audible vacuum leak inside the passenger compartment.
The air intake hood flapper vacuum line is disconnected....
The car came with a partially used intake gasket set. Just the throttle body gaskets were used from the kit. I'm sure I'll find a surprise in there too..
Unfortunately the car is in winter storage, so no work can be done on it. So, I've armed myself with the GM assembly manual and the shop manual as well..
Crossfire was produced for 3 model years, more than 35 years ago. Most techs now-a-days weren't even alive when Crossfire was introduced.
Melting Slicks
Joined: May 2021
Posts: 2,274
Likes: 1,321
From: Fleming Island, FL
http://repairs.willcoxcorvette.com/1...atic-detailed/
Thread Starter
Racer
Joined: Oct 2021
Posts: 436
Likes: 15
From: Maryland
Yea. sorry I know the wording is confusing. I've unplugged the one line going right into the air filter. There was another line that plugged into the manifold too ontop of it, I plugged that as well. Forgot what that line was.
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Drifting
Joined: Dec 2020
Posts: 1,586
Likes: 956
From: Central Florida
2024 Corvette of the Year Winner - Modified
2023 C3 of the Year Winner - Modified
2021 C3 of the Year Finalist - Modified
Hello, new 1982 owner here, my car is in great condition but idles too high (around 1000rpm warm). I heard idle should be around 650-700, my drive and reverse rpm's are fine. I started diagnosing vacuum leaks. I want to figure out what system is creating the leak, and if a vacuum leak is even the cause of the high idle. I removed and plugged both of the headlight lines going into the filter, and plugged the line going to the crossfire's air intake valve thing (it plugs into the back of one of the fuel injectors). Idles at around 900rpm now, still not close. What other non-essential vacuum lines can I plug to diagnose this? I just want to figure out if vacuum leak is the cause of the high idle, I will fix the leaks once I figure this out. Any help would be appreciated!
Melting Slicks
Joined: May 2021
Posts: 2,274
Likes: 1,321
From: Fleming Island, FL
https://www.ebay.com/itm/EVAP-Smoke-...-127632-2357-0
It will find vacuum leaks very quickly and in places you would never even think about checking.
Thread Starter
Racer
Joined: Oct 2021
Posts: 436
Likes: 15
From: Maryland
1000 RPM's is still to high. If you believe you still a vacuum leak get one these:
https://www.ebay.com/itm/EVAP-Smoke-...-127632-2357-0
It will find vacuum leaks very quickly and in places you would never even think about checking.
https://www.ebay.com/itm/EVAP-Smoke-...-127632-2357-0
It will find vacuum leaks very quickly and in places you would never even think about checking.
Melting Slicks
Joined: May 2021
Posts: 2,274
Likes: 1,321
From: Fleming Island, FL