hesitation during acceleration - The 1947 - Present Chevrolet & GMC Truck Message Board Network

orange-c10 · 10-23-2006, 12:20 AM

ive got a 70 c-10 with a 350. i had a edelbrock carb on the stock manifold and yesterday i installed a performer intake as well. after messing w/ timing and everything ive got a bad flat spot. idle is good but right off idle it just falls on its face. when i installed the distributor i mixed the two black wires on the coil. i dont know if maybe i fried something or what. truck ran great before i put on the new manifold.

orange-c10 · 10-23-2006, 03:02 PM

bump

casterbuster · 10-24-2006, 09:21 PM

sounds like a timing issue to me..

Texasdeere · 10-24-2006, 10:21 PM

Is the carburetor new or used? Usually this is a lean condition, such as a bad accelerator pump. Retarded ign timing from stock could cause a flat spot or weak off idle acceleration. Sometimes a weak accell pump can be partially masked by a little more timing advance too.

orange-c10 · 10-24-2006, 11:39 PM

brand new carb. i advanced the timing way off the scale and the flat spot went away. still pings when i get on it. should i advance it more??

Texasdeere · 10-25-2006, 09:34 AM

I would back off the timing until the pinging stops. The pinging or pre-ingnition is not good for your engine. If the flat spot comes back try just riching up your idle mixture screws a little and see if that helps. Listen to your engine idle when you do this, it will tell you where it likes it. Hopefully as you richin it up your idle will smooth out some meanig that it was too lean before.

A.P. · 10-25-2006, 12:41 PM

Orange C-10, check these videos from Edelbrock.
http://www.edelbrock.com/automotive_...ech_vids.shtml

**VetteVet** · 10-25-2006, 01:09 PM

Sounds to me like when you pulled the intake and the distributor you put the distributor back in about one tooth off. Check this by putting the timing mark on the balancer on the zero mark on the timing tab and pull the cap off the distributor and see if the rotor button lines up exactly with either no.1 or no.6 spark plug wire. If it doesn't then pull the distributor up just enough to align it. If you wired the coil in reverse polarity it will do exactly as you describe also.

68C15 · 10-25-2006, 01:43 PM

"2 black wires on coil" tells me it is a points setup. polarity is important. the "-" side of coil goes to dist. while the "+" side goes to ign. switch and starter.
when is the last time you set your dwell? IIRC it calls for 28-32* dwell at warm idle.
hope this helps

orange-c10 · 10-25-2006, 08:33 PM

deleted the points with one of those accel kits. the coil is wired properly. im going to turn the motor to the 0 mark and check the distributor. maybe i did get it off a little

10-23-2006, 12:20 AM	#1
orange-c10 Registered User Join Date: Sep 2006 Location: Oak Harbor , Wa Posts: 27	hesitation during acceleration ive got a 70 c-10 with a 350. i had a edelbrock carb on the stock manifold and yesterday i installed a performer intake as well. after messing w/ timing and everything ive got a bad flat spot. idle is good but right off idle it just falls on its face. when i installed the distributor i mixed the two black wires on the coil. i dont know if maybe i fried something or what. truck ran great before i put on the new manifold.

10-23-2006, 03:02 PM	#2
orange-c10 Registered User Join Date: Sep 2006 Location: Oak Harbor , Wa Posts: 27	Re: hesitaion during acceleration bump

10-24-2006, 09:21 PM	#3
casterbuster Mejor Que Nada Join Date: Jun 2006 Location: texas Posts: 232	Re: hesitaion during acceleration sounds like a timing issue to me.. __________________ The only thing that separates "Dreams" from "Reality" is TIME and MONEY!!!

10-24-2006, 10:21 PM	#4
Texasdeere Registered User Join Date: Sep 2006 Location: League City, Texas Posts: 732	Re: hesitaion during acceleration Is the carburetor new or used? Usually this is a lean condition, such as a bad accelerator pump. Retarded ign timing from stock could cause a flat spot or weak off idle acceleration. Sometimes a weak accell pump can be partially masked by a little more timing advance too.

10-24-2006, 11:39 PM	#5
orange-c10 Registered User Join Date: Sep 2006 Location: Oak Harbor , Wa Posts: 27	Re: hesitation during acceleration brand new carb. i advanced the timing way off the scale and the flat spot went away. still pings when i get on it. should i advance it more??

10-25-2006, 09:34 AM	#6
Texasdeere Registered User Join Date: Sep 2006 Location: League City, Texas Posts: 732	Re: hesitation during acceleration I would back off the timing until the pinging stops. The pinging or pre-ingnition is not good for your engine. If the flat spot comes back try just riching up your idle mixture screws a little and see if that helps. Listen to your engine idle when you do this, it will tell you where it likes it. Hopefully as you richin it up your idle will smooth out some meanig that it was too lean before.

10-25-2006, 12:41 PM	#7
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662	Re: hesitation during acceleration Orange C-10, check these videos from Edelbrock. http://www.edelbrock.com/automotive_...ech_vids.shtml

10-25-2006, 01:09 PM	#8
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,718	Re: hesitation during acceleration Sounds to me like when you pulled the intake and the distributor you put the distributor back in about one tooth off. Check this by putting the timing mark on the balancer on the zero mark on the timing tab and pull the cap off the distributor and see if the rotor button lines up exactly with either no.1 or no.6 spark plug wire. If it doesn't then pull the distributor up just enough to align it. If you wired the coil in reverse polarity it will do exactly as you describe also. __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative. Last edited by VetteVet; 10-25-2006 at 02:01 PM.

10-25-2006, 01:43 PM	#9
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	Re: hesitation during acceleration "2 black wires on coil" tells me it is a points setup. polarity is important. the "-" side of coil goes to dist. while the "+" side goes to ign. switch and starter. when is the last time you set your dwell? IIRC it calls for 28-32* dwell at warm idle. hope this helps Last edited by 68C15; 10-25-2006 at 01:44 PM.

10-25-2006, 08:33 PM	#10
orange-c10 Registered User Join Date: Sep 2006 Location: Oak Harbor , Wa Posts: 27	Re: hesitation during acceleration deleted the points with one of those accel kits. the coil is wired properly. im going to turn the motor to the 0 mark and check the distributor. maybe i did get it off a little

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