Conversions & Swaps LSX Engines in Non-LSX Vehicles
Sponsored by:
Sponsored by:

Stalling with hard braking

Thread Tools
 
Search this Thread
 
Old May 1, 2018 | 11:19 AM
  #1  
hemiqc2003's Avatar
Thread Starter
Teching In
 
Joined: Sep 2011
Posts: 42
Likes: 0
From: Franklin, Indiana
Default Stalling with hard braking

I have a 1966 Chevelle, manual brake car, 4L80E trans, L92 with LS3 intake, CNC ported LS3 heads, Speartech harness, Aeromotive fuel tank. Everything is new, not from a junkyard or Ebay or CL When I stop abruptly it will stall or it will drop to about 300 rpm flare up to around 1000 rpm and then stall. My tuner is at his wits end and has tried everything to get it to stop by to no avail. Anyone else had or seen this problem?
Reply
Old May 1, 2018 | 12:40 PM
  #2  
G Atsma's Avatar
TECH Senior Member
5 Year Member
Liked
Loved
Community Favorite
 
Joined: Jun 2016
Posts: 22,308
Likes: 3,624
From: Central Cal.
Default

Is your brake booster leaking air upon brake application? This would cause a severe lean condition that could stall an engine on very hard braking.
To check , with the engine running, sitting still, push very hard on the brakes. If the engine does as you describe, you found your problem.
Reply
Old May 1, 2018 | 12:48 PM
  #3  
hemiqc2003's Avatar
Thread Starter
Teching In
 
Joined: Sep 2011
Posts: 42
Likes: 0
From: Franklin, Indiana
Default

Manual Brakes
Reply
Old May 1, 2018 | 12:58 PM
  #4  
G Atsma's Avatar
TECH Senior Member
5 Year Member
Liked
Loved
Community Favorite
 
Joined: Jun 2016
Posts: 22,308
Likes: 3,624
From: Central Cal.
Default

Originally Posted by hemiqc2003
Manual Brakes
OOPS! Missed that... sorry
Reply
Old May 1, 2018 | 01:21 PM
  #5  
1964SS's Avatar
TECH Fanatic
10 Year Member
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: Aug 2012
Posts: 1,539
Likes: 85
From: Mesa, Arizona
Default

Do you have the brake switch signal tied in?
Reply
Old May 1, 2018 | 09:06 PM
  #6  
Mr.Bu's Avatar
On The Tree
15 Year Member
Photogenic
Photoriffic
Shutterbug
 
Joined: Dec 2009
Posts: 174
Likes: 2
From: Aurora IL
Default

There should be a light blue tcc wire that goes to your brake switch behind your pedal. It unlocks the converter when it gets 12v. Use a test light and move the brake pedal, there’s only 2 blades on the switch and one will light up the tester with brakes applied. If it’s not unlocking, I ouldnt drive it around you could burn your trans up.
Reply




All times are GMT -5. The time now is 02:37 PM.

story-0
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

Don't get dad new socks or a grill brush this year.

By Brett Foote | 2026-06-09 14:55:56


VIEW MORE
story-1
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-05-28 11:05:11


VIEW MORE
story-2
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-3
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-4
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-5
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-6
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-7
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-8
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-9
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE