Hard start
Joined: Nov 2008
Posts: 2,093
Likes: 175
From: Milwaukee
Car: 92 Firebird, 77 Trans Am SE, 86 Z28
Engine: 5.7 HSR, T/A 6.6, empty
Transmission: T-5, TH350, T-5
Axle/Gears: 3.08 posi, 3.23 posi, 3.23
Re: Hard start
Describe the hard start. Doesn't crank...cranks slow.... cranks very fast....spits and sputters while cranking... or a video
Gotta give us something to go on.
Gotta give us something to go on.
Joined: Sep 2005
Posts: 27,882
Likes: 2,434
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Hard start
Sounds like the fuel reaching the carb gets very hot while it sits and immediately spews into foam when it goes from fuel system pressure (4 psi or whatever) to atmospheric. Kinda the same deal as shaking up a closed warm Coke bottle and then popping off the top.
Try creating the conditions that produce it. For me, it has always been, driving it around on a hot day in traffic esp with the AC on, shutting off the motor, then coming back and trying to start it after maybe 10-15 min. Like going to the store or something. While waiting, pop the air cleaner lid off, and watch down into the carb while your assistant tries to start it. If you see gaoline bubbling up out of every hole in the top of the carb and flooding into the intake, then that's what it is.
Very common. Usually derives from the block heating up the fuel pump, in my experience.
Try adding a 2nd fuel pump gasket. If that helps, get one of these. https://www.cantonracingproducts.com...vy-fuel-pumps/
And, if any of your fuel lines are routed closer to any exhaust parts than they were when stock, look into moving or shielding them.
Try creating the conditions that produce it. For me, it has always been, driving it around on a hot day in traffic esp with the AC on, shutting off the motor, then coming back and trying to start it after maybe 10-15 min. Like going to the store or something. While waiting, pop the air cleaner lid off, and watch down into the carb while your assistant tries to start it. If you see gaoline bubbling up out of every hole in the top of the carb and flooding into the intake, then that's what it is.
Very common. Usually derives from the block heating up the fuel pump, in my experience.
Try adding a 2nd fuel pump gasket. If that helps, get one of these. https://www.cantonracingproducts.com...vy-fuel-pumps/
And, if any of your fuel lines are routed closer to any exhaust parts than they were when stock, look into moving or shielding them.
Junior Member
Joined: Jul 2022
Posts: 2
Likes: 1
From: FLORIDA
Car: 85 Z28 Sport
Engine: 383
Axle/Gears: 3.73
Re: Hard start
depending on the carb, get a quick fuel insulator and a 1/2 in carb adaptor that is made of either aluminum or composite, sold at holly or the other places for 114 bucks plus tax. if you have a steel line to the carb, make it rubber from the fuel pump, if that helps maybe an air gap intake will help too
Last edited by 85Z28SPORT; Jul 11, 2022 at 10:30 PM. Reason: adding words
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