stumbles at idle - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bucket · 09-18-2003, 10:14 AM

it smooths out once the rpms get up a little but it seems to hesitate a little at idle and while getting off idle. 400 miles on rebuild new hei, etc. edelbrock carb. just started yesterday. ideas? I have already checked wires, vacuum connections. hope its not a camshaft.

hgs_notes · 09-18-2003, 10:29 AM

Could be several things, but I'd start with the carb. It could be hesitating because it's not getting enough fuel at acceleration. This could be the accelerator pump or just the cam size for the pump is to small. It could also be flooding on acceleration, but I'd lean to the not enough fuel.

Could also just be timing. Mine hesitates a bit when the engine is not completely warmed up. I don't have the choke hooked up. Once it's hot the problem goes away.

HG

bucket · 09-18-2003, 10:57 AM

the stumble off idle is very slight. engine temp seems to have nothing to do with symptoms. the biggest thing is the irregular idle. seems to surge and/or miss almost like its going to stall.

tom hand · 09-18-2003, 12:43 PM

What size cam do you have? How many inches of vacuum are you pulling at idle.

**COBALT** · 09-18-2003, 01:58 PM

What's your timing set at? You're using vacuum advance right?

bucket · 09-18-2003, 02:33 PM

thanks for the replys guys.

camshaft is stock for a small journal 327. not sure of the exact specs. have not checked vacuum, however the only thing i have under vacuum is the advance and pcv.

timiming is set about 8 btdc.

09-18-2003, 10:14 AM	#1
bucket Registered User Join Date: Aug 2001 Location: Shawnee, KS Posts: 923	stumbles at idle it smooths out once the rpms get up a little but it seems to hesitate a little at idle and while getting off idle. 400 miles on rebuild new hei, etc. edelbrock carb. just started yesterday. ideas? I have already checked wires, vacuum connections. hope its not a camshaft.

09-18-2003, 10:29 AM	#2
hgs_notes GEARHEAD Join Date: Aug 2003 Location: MN Posts: 6,122	Could be several things, but I'd start with the carb. It could be hesitating because it's not getting enough fuel at acceleration. This could be the accelerator pump or just the cam size for the pump is to small. It could also be flooding on acceleration, but I'd lean to the not enough fuel. Could also just be timing. Mine hesitates a bit when the engine is not completely warmed up. I don't have the choke hooked up. Once it's hot the problem goes away. HG __________________ If no one knows what you're doing, they can't tell you you're doing it wrong HG's Dream Car Build - Shelby Cobra Kit Build your own adjustable track bar 71 Long Fleet C/10 72 Jimmy 4x4 (Junkyard Jimmy) HG's Plow Truck '78 K35 Dually Bigass Farm Truck HG's thread of miscellaneous stuff

09-18-2003, 12:43 PM	#4
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	What size cam do you have? How many inches of vacuum are you pulling at idle. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

09-18-2003, 01:58 PM	#5
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	What's your timing set at? You're using vacuum advance right? __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

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09-18-2003, 10:57 AM	#3
bucket Registered User Join Date: Aug 2001 Location: Shawnee, KS Posts: 923	the stumble off idle is very slight. engine temp seems to have nothing to do with symptoms. the biggest thing is the irregular idle. seems to surge and/or miss almost like its going to stall.

09-18-2003, 02:33 PM	#6
bucket Registered User Join Date: Aug 2001 Location: Shawnee, KS Posts: 923	thanks for the replys guys. camshaft is stock for a small journal 327. not sure of the exact specs. have not checked vacuum, however the only thing i have under vacuum is the advance and pcv. timiming is set about 8 btdc.



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