bogging after truck upshifts... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Prerunner1982 · 01-13-2003, 02:08 AM

ok... let me attempt to explain this..

when i get on it my truck will shift into what is commonly known as passing gear..truck winds up then takes off... just fine.. but when it downshifts it bogs, will pick up when i let off... any ideas as to what might cause this? other than that, truck seem to run really well... ask riptide.. he liked the sound of it!

thanks for any help

Jon

79BIG10 · 01-13-2003, 03:58 AM

When you get on it the carb's linkage activates the kickdown cable (you got a TH350 right?) which makes it downshift to the 2nd gear (passing gear). When the tranny downshifts the carb is probably at full throttle. This is the problem. You're getting plenty of fuel but not enough air. You need to adjust the secondaries for more air. The Q-jets have such large secondaries they need more air to combine with the fuel to compensate for the larger barrels. I don't know for sure how to compensate for this but I think that Swervin may have a better way to help you on that.

Prerunner1982 · 01-13-2003, 04:15 AM

*lightbulb* dirty air filter? i need to clean out my K&N tomorrow.. see if that helps...

79BIG10 · 01-13-2003, 04:32 AM

Not just that but may need more to do with the actual fine adjustment screws.

01-13-2003, 02:08 AM	#1
Prerunner1982 Registered User Join Date: Oct 2002 Location: Edmond, OK Posts: 5,904	bogging after truck upshifts... ok... let me attempt to explain this.. when i get on it my truck will shift into what is commonly known as passing gear..truck winds up then takes off... just fine.. but when it downshifts it bogs, will pick up when i let off... any ideas as to what might cause this? other than that, truck seem to run really well... ask riptide.. he liked the sound of it! thanks for any help Jon __________________ Jon 1982 Chevy Silverado 350/th350.... RETIRED 1993 Jeep XJ 2 door(Cherokee) 4wd 4.0ltr/AX-15 (5spd)/NP231 .... Oklahoma Roll Call

01-13-2003, 03:58 AM	#2
79BIG10 I'm back with 2nd truck! Join Date: Feb 2002 Location: Texas Posts: 3,774	When you get on it the carb's linkage activates the kickdown cable (you got a TH350 right?) which makes it downshift to the 2nd gear (passing gear). When the tranny downshifts the carb is probably at full throttle. This is the problem. You're getting plenty of fuel but not enough air. You need to adjust the secondaries for more air. The Q-jets have such large secondaries they need more air to combine with the fuel to compensate for the larger barrels. I don't know for sure how to compensate for this but I think that Swervin may have a better way to help you on that. __________________ 1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson

01-13-2003, 04:15 AM	#3
Prerunner1982 Registered User Join Date: Oct 2002 Location: Edmond, OK Posts: 5,904	lightbulb dirty air filter? i need to clean out my K&N tomorrow.. see if that helps... __________________ Jon 1982 Chevy Silverado 350/th350.... RETIRED 1993 Jeep XJ 2 door(Cherokee) 4wd 4.0ltr/AX-15 (5spd)/NP231 .... Oklahoma Roll Call

01-13-2003, 04:32 AM	#4
79BIG10 I'm back with 2nd truck! Join Date: Feb 2002 Location: Texas Posts: 3,774	Not just that but may need more to do with the actual fine adjustment screws. __________________ 1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson



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