Engine Stalls on Hard Braking
July 3rd, 2015, 08:04 PM
#1
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Location: Southeast Michigan
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Engine Stalls on Hard Braking
My 1978 Starfire with the Chevy 305 (from the factory), 2 bbl 2GC carb, and 4-speed manual transmission. Electronic ignition from the factory. The car is as it was from the factory.
When the car is cold everything is fine. When it warms up, and I come to a hard stop, it dies (yes I have the clutch pedal depressed or am in neutral). Starts up again immediately. I unplugged the brake booster and capped the line from the carb. No difference, so it doesn't seem to be related to the brake booster vacuum. If I slow down very slowly and come to a gentle stop, it stays at idle no problem. I replaced all of the vacuum lines last fall, there are none missing. I replaced the EGR valve last fall also. I have been noticing a rough idle when warm lately.
Any ideas on where to start with this?
When the car is cold everything is fine. When it warms up, and I come to a hard stop, it dies (yes I have the clutch pedal depressed or am in neutral). Starts up again immediately. I unplugged the brake booster and capped the line from the carb. No difference, so it doesn't seem to be related to the brake booster vacuum. If I slow down very slowly and come to a gentle stop, it stays at idle no problem. I replaced all of the vacuum lines last fall, there are none missing. I replaced the EGR valve last fall also. I have been noticing a rough idle when warm lately.
Any ideas on where to start with this?
Last edited by starfire; July 4th, 2015 at 05:43 AM.
July 4th, 2015, 05:44 AM
#2
'87 Delta 88 Royale
Join Date: Dec 2010
Location: Margate, England
Posts: 2,513
What is your idle speed?. Could be the engine needs a tune up, possibly you have a vacuum leak somewhere.
A proper tune up should reveal any underlying problems, if you need new intake gaskets or whatever you would need a tune up after the repair work anyway.
Roger.
A proper tune up should reveal any underlying problems, if you need new intake gaskets or whatever you would need a tune up after the repair work anyway.
Roger.
July 4th, 2015, 08:47 AM
#5
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Professionally rebuilt carb. Tuned up last fall to all factory specs. Low idle speed is 600, per spec. All new vacuum lines. I will test for vacuum leak with carb cleaner later today. If that is negative I guess I'll run through the tune up again.
July 4th, 2015, 06:42 PM
#6
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OK, checked for vacuum leaks and found none. Checked tune-up and everything is as it should be. 4* @ 600 rpm with distributor vacuum line plugged and trans in neutral. Low idle set to 600 rpm with EGR vacuum and purge lines plugged.
Took it out for a test drive tonight, took the same route last night and could not get it to die when I braked hard. Hmmmm. Idle still seems rough though.
Took it out for a test drive tonight, took the same route last night and could not get it to die when I braked hard. Hmmmm. Idle still seems rough though.
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