I need some help with my new engine
#109295
08/23/08 06:54 PM
08/23/08 06:54 PM
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Joined: Aug 2003
Posts: 1,345 Rohnert Park, Ca
ryan053
OP
pro stock
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OP
pro stock
Joined: Aug 2003
Posts: 1,345
Rohnert Park, Ca
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I just had my new engine broken in and dynoed. Its a 383 stroked to 434. Its got edelbrock heads, a comp cams xe275hl cam, 9.7:1 compression. I use 91 octane gas. the carb is a 750 DP with 71/78 jets. The timing is set at 12/30 if i remember correctly. i have the idle at 850. On the dyno it made 375hp/401tq at the wheels. Now my issue is this. It runs on after i shut it off. It dies after a few seconds. I cant keep the car running with the idle any lower. Manifold vacuum is a steady 10.5. secondly when i try to do a brake stand or apply the gas with my foot on the brake it pops and sputters out of the carb. a few times puffs of gray smoke have come out. The car is a 4sp and has 3.91's if it makes a difference. Anyone have any ideas on what to try next?
Last edited by ryan053; 08/24/08 10:53 PM.
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Re: I need some help with my new engine
[Re: ryan053]
#109296
08/23/08 07:28 PM
08/23/08 07:28 PM
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Joined: Aug 2006
Posts: 2,525 God's Country Maryland
GODSCOUNTRY340
master
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master
Joined: Aug 2006
Posts: 2,525
God's Country Maryland
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You may have a vacuum leak in the power brake booster. Try unhooking the vacuum hose from the manifold to the booster, plug it, and see if there's any difference.
I love the smell of Deer guts in the morning, it smells like... VICTORY!
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Re: I need some help with my new engine
[Re: ryan053]
#109298
08/23/08 08:08 PM
08/23/08 08:08 PM
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Joined: Sep 2005
Posts: 12,481 Chino Valley
RodStRace
I Live Here
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I Live Here
Joined: Sep 2005
Posts: 12,481
Chino Valley
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Quote:
i have the idle at 850. Now my issue is this. It runs on after i shut it off. It dies after a few seconds. I cant keep the car running with the idle any lower. Manifold vacuum is a steady 10.5.
850 should be low enough to kill it. Either it has a vacuum leak, or you have Alt feedback. See "My car continues to run after I switch the key off." post. Does the carb adjust normally? Idle screws kill it @ about a half turn out, smooth idle @ about 1-2 turns out? If not, check for leaks.
Quote:
secondly when i try to do a brake stand or apply the gas with my foot on the brake it pops and sputters out of the carb.
This may be the vacuum leak, so fix that first. If that's not the issue, you need to tune the carb. If it's popping right when you hit it, Accel pump shot and/or squirter. If it hits then bogs, power circuit and/or mains. This isn't the best way to check drivability, either, but I get what you are trying for...
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Re: I need some help with my new engine
[Re: ryan053]
#109303
08/24/08 08:22 PM
08/24/08 08:22 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Re: I need some help with my new engine
[Re: ryan053]
#109306
08/25/08 06:41 PM
08/25/08 06:41 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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shut it off in gear. then shift to park.
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