Barracuda Challenger Forum

Author Topic: Engine Surging in Drive with Brake Applied  (Read 133 times)

Offline wantone

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Engine Surging in Drive with Brake Applied
« on: April 16, 2017 - 07:38:24 PM »
Hi Gents - 71' Cuda with 383 automatic.   Has new Carb (QF 750) / Summit magnetic dizzy.  With my foot on the brake at a stoplight, the engine surges.   The car idles, cruises and accelerates fine.   Little Help?
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Offline cudabob496

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Re: Engine Surging in Drive with Brake Applied
« Reply #1 on: April 16, 2017 - 08:18:43 PM »
vacuum leak?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
Up to 4000 RPM, Warp Speed, Up to 5000, Rediculous Speed, Up to 6000 RPM, Ludicrous Speed!

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

Offline Strawdawg

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Re: Engine Surging in Drive with Brake Applied
« Reply #2 on: April 17, 2017 - 01:09:19 PM »
Too high an idle speed? 


Offline burdar

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Re: Engine Surging in Drive with Brake Applied
« Reply #3 on: April 17, 2017 - 02:05:47 PM »
I'm the last person to ask questions regarding tuning but...I'm pretty sure this problem can occur if the idle speed is high AND the mechanical advance springs in the distributor are light.  Basically, the timing wants to advance even at an idle.  Maybe I'm way off but I seem to remember reading about this.

Offline Strawdawg

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Re: Engine Surging in Drive with Brake Applied
« Reply #4 on: April 17, 2017 - 02:23:31 PM »
Yes, that will do it

Offline jhaag

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Re: Engine Surging in Drive with Brake Applied
« Reply #5 on: April 17, 2017 - 02:35:37 PM »
Do you have power brakes? Could be a leaking vacuum booster. If it idles correctly in neutral/park, then the booster could be the culprit.
love 70 Challengers

Offline cudabob496

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Re: Engine Surging in Drive with Brake Applied
« Reply #6 on: April 17, 2017 - 02:52:50 PM »
disconnect vacuum advance and see what happens
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
Up to 4000 RPM, Warp Speed, Up to 5000, Rediculous Speed, Up to 6000 RPM, Ludicrous Speed!

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"