Stumbling and dies when hot?
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Joined: Aug 1999
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From: At my Bar drinking and wrenching in Lafayette Colorado
A 1978 Vette does not have an ECM.... What year configuration are you running?
1978 Corvette does not have an electric choke that can be "unplugged." Sounds like you have a hacked, incorrect, non-stock configuration that you need to get ironed out. If you "unplug" an electric choke after it warms up, the choke will then close and it will kill the engine from a flood-out condition.
Sounds like you have a hacked mess on your hands...
Sounds like you have a hacked mess on your hands...
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Joined: Mar 2016
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A 1978 Vette does not have an ECM.... What year configuration are you running?
I said ECM but meaning ignition module. I have 4 cars I'm working on currently so...
1978 Corvette does not have an electric choke that can be "unplugged." Sounds like you have a hacked, incorrect, non-stock configuration that you need to get ironed out. If you "unplug" an electric choke after it warms up, the choke will then close and it will kill the engine from a flood-out condition.
Sounds like you have a hacked mess on your hands...
I said ECM but meaning ignition module. I have 4 cars I'm working on currently so...
1978 Corvette does not have an electric choke that can be "unplugged." Sounds like you have a hacked, incorrect, non-stock configuration that you need to get ironed out. If you "unplug" an electric choke after it warms up, the choke will then close and it will kill the engine from a flood-out condition.
Sounds like you have a hacked mess on your hands...
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Joined: Mar 2016
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Update, changed the Fuel pump and drained the tank. Refilled with Non-ethanol that I was lucky to have down the street. Two shorter drives so far that went well until I get home and park/idle. It will occasionally stumble a few seconds but come right back. May go several minutes before it stumbles again but carb seems to adjust and comes right back. I can clearly see the fuel bowl is full and stays full. Squirters work fine.
Thinking I had Vapor lock from poor pump/ethanol gas. Can’t really test without filling with assuming to have ethanol gas.
The remaining stumbling I would think is from inside the carb but only within a small section. Likely a carb design issues, maybe a rebuild would help?
Thinking I had Vapor lock from poor pump/ethanol gas. Can’t really test without filling with assuming to have ethanol gas.
The remaining stumbling I would think is from inside the carb but only within a small section. Likely a carb design issues, maybe a rebuild would help?
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Joined: Mar 2016
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Thread Starter
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Joined: Mar 2016
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Got the Crab rebuild complete, no surprises. Back together set the fuel/air screws at 4.5 turns out and it starts right up on the key. Before taking on a drive wanted to set the fuel/air screws with a vacuum gauge. I’ve connected my gauge at the PCV hose, port just above the F/A screws and to the brake booster connection but adjusting the screws in and out has no effect on the vacuum. I’m pretty steady at 14-15 vacuum from 5.5 out to 1.5 out. No setting adjustments seems to impact the Vacuum or idle. What am I doing wrong.
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Got a carb rebuild done and that seems to have fixed the slight periods of idle drop when hot fixed. Haven’t had the car die when hot in a couple of weeks since replacing the fuel pump and refilled with non-Ethanol. Will have to figure out when/if I can go back with regular Unleaded. Hoping it’s just a summer issue.
