Hesitation - The 1947 - Present Chevrolet & GMC Truck Message Board Network

skokie · 12-18-2003, 01:47 AM

I have a hesitation when I hit the gas pedal. Timing is at 10 adv, Hei Ignition, plugs are gapped at 45 and are new. Plug wires are new. I do have a small crack in the passenger side exhaust manifold that is getting replaced with headers com January. An ideas on what it could be?

Thanks

oldsub86 · 12-18-2003, 01:50 AM

Accelerator pump in the carb?

Rooster's 67 · 12-18-2003, 01:53 AM

low float level, accelerator pump, weak coil, weak fuel pump, weak ignition pick up...
what is the type of hesitation and does it make any noise(pops or back fire through carb?)
is it only on hard accel or only on slow accel

dinnut · 12-18-2003, 01:56 AM

cat on manifold?

skokie · 12-18-2003, 02:04 AM

No noise and its a healthy accel. I wouldnt call it a stomp though. And no cat either.

Rooster's 67 · 12-18-2003, 02:10 AM

accel pump is what it sounds like. what kinda carb?

skokie · 12-18-2003, 02:14 AM

Holley 600. 80457-2. I just put a new edelbrock 2101 manifold on it a week ago. I will check the bowls this weekend and see what they are looking like.

Rooster's 67 · 12-18-2003, 02:18 AM

check the accel pump and you may look and see if you can change the accel pump cams on that carb. may need a different ramp/cam. not a big holly fan but someone else may know.

skokie · 12-18-2003, 02:29 AM

I will do that to. Thanks for the help.

tom hand · 12-18-2003, 12:09 PM

I not familiar with that Holley number...is it a square bore? If it is are you using edelbrocks plate to put a square bore carb on a speadbore intake? If not you may have a vacuum leak under the carb.

skokie · 12-18-2003, 05:52 PM

Yep its a square bore carb and I do have the plate for it.

EdB · 12-18-2003, 09:19 PM

If all the above doesn't work, look for a worn cam lobe.

EdB

12-18-2003, 01:47 AM	#1
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,354	Hesitation I have a hesitation when I hit the gas pedal. Timing is at 10 adv, Hei Ignition, plugs are gapped at 45 and are new. Plug wires are new. I do have a small crack in the passenger side exhaust manifold that is getting replaced with headers com January. An ideas on what it could be? Thanks

12-18-2003, 01:50 AM	#2
oldsub86 Registered User Join Date: Dec 2002 Location: Canada Posts: 695	Accelerator pump in the carb? __________________ 1968 Chevy - 292 with a powerglide

12-18-2003, 01:53 AM	#3
Rooster's 67 Registered User Join Date: Sep 2003 Location: DFW Posts: 765	low float level, accelerator pump, weak coil, weak fuel pump, weak ignition pick up... what is the type of hesitation and does it make any noise(pops or back fire through carb?) is it only on hard accel or only on slow accel __________________ The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?

12-18-2003, 01:56 AM	#4
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	cat on manifold? __________________ 70 longbed 496/th400/Ford 9"

12-18-2003, 02:10 AM	#6
Rooster's 67 Registered User Join Date: Sep 2003 Location: DFW Posts: 765	accel pump is what it sounds like. what kinda carb? __________________ The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?

12-18-2003, 02:04 AM	#5
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,354	No noise and its a healthy accel. I wouldnt call it a stomp though. And no cat either.

12-18-2003, 02:14 AM	#7
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,354	Holley 600. 80457-2. I just put a new edelbrock 2101 manifold on it a week ago. I will check the bowls this weekend and see what they are looking like.

12-18-2003, 02:18 AM	#8
Rooster's 67 Registered User Join Date: Sep 2003 Location: DFW Posts: 765	check the accel pump and you may look and see if you can change the accel pump cams on that carb. may need a different ramp/cam. not a big holly fan but someone else may know. __________________ The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?

12-18-2003, 02:29 AM	#9
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,354	I will do that to. Thanks for the help.

12-18-2003, 12:09 PM	#10
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	I not familiar with that Holley number...is it a square bore? If it is are you using edelbrocks plate to put a square bore carb on a speadbore intake? If not you may have a vacuum leak under the carb. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

12-18-2003, 05:52 PM	#11
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,354	Yep its a square bore carb and I do have the plate for it.

12-18-2003, 09:19 PM	#12
EdB Registered User Join Date: Jan 2003 Location: Gulfport Ms Posts: 401	If all the above doesn't work, look for a worn cam lobe. EdB



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