weired issue - The 1947 - Present Chevrolet & GMC Truck Message Board Network

76bonanza · 12-14-2005, 10:23 AM

This morning get in my truck drive about 3 miles stop at store when I stop in gear truck can not even hold idle drops to like 150rpm stumble starts to die shift into park goes up to about 500rpm still really ruff. Shut it down look underhood no lines off or plugs unpluged. Go into store come out press gas to floor to make sure choke is set good fire it up runs great all the way to work. run it up to about 3000rpm a few times all good idles smooth as silk. Now to the weather about 39 foggy and misty rained last night, really humid. could this just be a choke issue maybe did not set good or came out to soon?

1969 C/K CST · 12-14-2005, 10:26 AM

Could be a change in climate issue. I used to reset my quad every change in season.

boundstaffpress · 12-14-2005, 10:33 AM

quadrajet primaries can get stuck inside the body when they experience climate change. When the engine is off for a while, the temperatures even out, and things return to normal. Carb starts back up in "hot start". Happens occasionslly to me.

hope your day gets better.

76bonanza · 12-14-2005, 10:58 AM

running a holley should have stated that.

1969 C/K CST · 12-14-2005, 11:09 AM

Quote:

Originally Posted by 76bonanza

running a holley should have stated that.

Notorious for changing with climate, humidity, and barametric pressure.

farside847 · 12-14-2005, 12:02 PM

sounded like vapor lock to me.

jhow66 · 12-14-2005, 12:08 PM

Carb. Icing--right temp and right humidity =frost buildup on carb blocking idle air bleeds-dies -heat from engine melts frost-starts and run fine. You now know why the hot air tube to air cleaner is for.

sneakysnake · 12-14-2005, 03:20 PM

With the high humidity you may have plug wires hopping a spark. One good way to tell is start it cold in the dark, it will look like the 4th of july.

**Green Machine** · 12-14-2005, 05:36 PM

Quote:

Originally Posted by jhow66

Carb. Icing--right temp and right humidity =frost buildup on carb blocking idle air bleeds-dies -heat from engine melts frost-starts and run fine. You now know why the hot air tube to air cleaner is for.

Yep - Carb icing, I'll bet money on it. As the gas vaporizes in the carb, it cools it down below freezing, with high humidty and temps in the 30's the carb will ice when conditions are right. My holley does that to. Add a carb air heat tube, or what I do is run gasahol 10 percent blend in the winter. The alcohol seems to keep it from icing. When the air is colder and drier, icing isn't near as likely to happen. Temps in the 20's and 30's and humid makes mine ice up.

vtblazer · 12-14-2005, 06:44 PM

Quote:

Originally Posted by jhow66

Carb. Icing--right temp and right humidity =frost buildup on carb

High humidity and near freezing temps, a carbs worst nightmare without a heat tube.

bad68bowtie · 12-15-2005, 12:55 AM

Same thing happened to me with my Edelbrock on the way to school one mornin, pretty much the exact same conditions. It finally died in the parkin lot but I cranked it and revved it a little and all was fine, hasn't done it since, figured it was just the cold.

bad68bowtie · 12-15-2005, 12:57 AM

And we're supposed to be gettin freezin rain here tonight, should make things interestin in the mornin. I hate winter...

12-14-2005, 10:23 AM	#1
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	weired issue This morning get in my truck drive about 3 miles stop at store when I stop in gear truck can not even hold idle drops to like 150rpm stumble starts to die shift into park goes up to about 500rpm still really ruff. Shut it down look underhood no lines off or plugs unpluged. Go into store come out press gas to floor to make sure choke is set good fire it up runs great all the way to work. run it up to about 3000rpm a few times all good idles smooth as silk. Now to the weather about 39 foggy and misty rained last night, really humid. could this just be a choke issue maybe did not set good or came out to soon? __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

12-14-2005, 10:26 AM	#2
1969 C/K CST A.K.A- Crummy Join Date: Jun 2005 Location: NC foothills Posts: 3,025	Re: weired issue Could be a change in climate issue. I used to reset my quad every change in season. __________________ 2003 Silverado Z71 Are fishermen all liars?

12-14-2005, 10:33 AM	#3
boundstaffpress Jamie Hyneman is my twin Join Date: Nov 2005 Location: La Junta, Colorado Posts: 705	Re: weired issue quadrajet primaries can get stuck inside the body when they experience climate change. When the engine is off for a while, the temperatures even out, and things return to normal. Carb starts back up in "hot start". Happens occasionslly to me. hope your day gets better. __________________ Justin SOLD 1967 K10 Fleetside, 283, Front and Rear Posi SOLD Color Wiring Diagrams Now in High Resolution V8 and Cab and Cab and Chassis

12-14-2005, 10:58 AM	#4
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	Re: weired issue running a holley should have stated that. __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

12-14-2005, 12:02 PM	#6
farside847 Registered User Join Date: Feb 2005 Location: Bay Area, California Posts: 995	Re: weired issue sounded like vapor lock to me. __________________ 1971 Chevy C10 Shortbed Stepside, 307v8 3-on-the-tree

12-14-2005, 12:08 PM	#7
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: weired issue Carb. Icing--right temp and right humidity =frost buildup on carb blocking idle air bleeds-dies -heat from engine melts frost-starts and run fine. You now know why the hot air tube to air cleaner is for. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

12-14-2005, 03:20 PM	#8
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	Re: weired issue With the high humidity you may have plug wires hopping a spark. One good way to tell is start it cold in the dark, it will look like the 4th of july.

12-15-2005, 12:55 AM	#11
bad68bowtie On the college boy budget... Join Date: Oct 2005 Location: Athens, Georgia Posts: 370	Re: weired issue Same thing happened to me with my Edelbrock on the way to school one mornin, pretty much the exact same conditions. It finally died in the parkin lot but I cranked it and revved it a little and all was fine, hasn't done it since, figured it was just the cold. __________________ -'68 C10 short/step- 350/350

12-15-2005, 12:57 AM	#12
bad68bowtie On the college boy budget... Join Date: Oct 2005 Location: Athens, Georgia Posts: 370	Re: weired issue And we're supposed to be gettin freezin rain here tonight, should make things interestin in the mornin. I hate winter... __________________ -'68 C10 short/step- 350/350



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