Author Topic: Hesitant on take-off  (Read 359 times)

Offline philo_beddoe

  • Senior Member
  • ****
  • Posts: 2502
  • 77 C-10, 350 4bbl-qjet
Hesitant on take-off
« on: February 09, 2019, 01:03:55 PM »
Roads were clean so took out the 77 for a mid-winter ride. Drove for  1/2 hour all fine. Stopped for a couple hours, on way back home noticed when first pressing the gas pedal accelling was very hesitant. Then as pedal pressed further down it seemed fine.  At take off or when moving,,same thing. Idle seems fine, revving in idle seems fine and smooth. From foot off the pedal to probably 1/3 of the way down its a little skippy and hesitant and boggy.  Looking for some answers. Thanks...
350, 4bbl qjet.

Ps. Hope this reaches VZ. He knows my truck better than i do!
« Last Edit: February 09, 2019, 01:06:40 PM by philo_beddoe »
Behold, the day of the LORD cometh, and thy spoil shall be divided in the midst of thee.  Zechariah 14:1

Offline zieg85

  • Carl
  • Site Supporters
  • Senior Member
  • ******
  • Posts: 6920
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: Hesitant on take-off
« Reply #1 on: February 09, 2019, 02:39:26 PM »
Just a guess but has the vacuum advance on your distributor ever been replaced?
1985 C30 Custom Deluxe Ext. cab 5.7L TH400 4.56 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 17167
Re: Hesitant on take-off
« Reply #2 on: February 09, 2019, 07:22:55 PM »
Fresh fuel? Did you pop the air cleaner lid off?
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

Offline philo_beddoe

  • Senior Member
  • ****
  • Posts: 2502
  • 77 C-10, 350 4bbl-qjet
Hesitant on take-off
« Reply #3 on: February 09, 2019, 09:27:12 PM »
Zieg: only when we put the new engine in a couple years ago, ran like a sewing machine ever since.

VZ: That was my first thought, so i immediately went and filled up (from half tank). Thought maybe some moisture got in there, i filled it in december and even put some dry gas in the tank, and that was the last time i drove it.  It was fine this morning, then half way back home i noticed it.  I did pop the air cleaner off, but what am i looking for??
Behold, the day of the LORD cometh, and thy spoil shall be divided in the midst of thee.  Zechariah 14:1

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 17167
Re: Hesitant on take-off
« Reply #4 on: February 10, 2019, 08:21:55 AM »
Make sure no mice got in there. Clean element, choke working, accelerator pump is discharging. Those are preliminary checks. Make sure no vacuum lines popped off etc.
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

Offline philo_beddoe

  • Senior Member
  • ****
  • Posts: 2502
  • 77 C-10, 350 4bbl-qjet
Re: Hesitant on take-off
« Reply #5 on: February 10, 2019, 04:00:40 PM »
Ok, will do. Will update...
Behold, the day of the LORD cometh, and thy spoil shall be divided in the midst of thee.  Zechariah 14:1

Offline philo_beddoe

  • Senior Member
  • ****
  • Posts: 2502
  • 77 C-10, 350 4bbl-qjet
Hesitant on take-off
« Reply #6 on: February 11, 2019, 02:33:00 PM »
Well, i didnt actually "do" much, just removed the air cleaner and inspected everything and cleaned up all the moving parts. Put it all back together and now it runs like driving it home from the dealer..quiet, smooth, fast and responsive. I only went for a few mile test. Next nice day i'll head out on the open road to and fro.

Some folks aint big on over the counter additives, but is there anything out there that will condition, clean and draw out any moisture in the fuel system from tank to carb? The only thing i did not use this year that i did last was add the standard red Sta-bil.
« Last Edit: February 11, 2019, 02:35:31 PM by philo_beddoe »
Behold, the day of the LORD cometh, and thy spoil shall be divided in the midst of thee.  Zechariah 14:1

Offline zieg85

  • Carl
  • Site Supporters
  • Senior Member
  • ******
  • Posts: 6920
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: Hesitant on take-off
« Reply #7 on: February 11, 2019, 03:10:52 PM »
Gas now a days is junk.  If you can find ethanol free gas go for it.  Gas additives are not my expertise.  If it were me I would run everything dry and add back a gallon back of treated gas for winter storage. 
1985 C30 Custom Deluxe Ext. cab 5.7L TH400 4.56 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 17167
Re: Hesitant on take-off
« Reply #8 on: February 11, 2019, 05:17:29 PM »
Don't run any additives until you are driving the truck. I've seen fuel additives wreak havoc after being added and then the vehicle sits.

I would also recommend filling the tank as opposed to leaving it low when it sits. Leaving space leaves more room for moisture and oxygen.
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

Offline philo_beddoe

  • Senior Member
  • ****
  • Posts: 2502
  • 77 C-10, 350 4bbl-qjet
Hesitant on take-off
« Reply #9 on: February 12, 2019, 07:58:32 AM »
Ok thanks a whole lot. Perhaps thats what went wrong-putting in an additive then sitting. I was told todays fuel can start causing problems after just six weeks of sitting. The problem around here in the winter is the roads are hardly ever salt free. Not much opportunities to get out.

Oh, BTW, someone gave me some seafoam, is that stuff okay??
Behold, the day of the LORD cometh, and thy spoil shall be divided in the midst of thee.  Zechariah 14:1

Offline Henry

  • Frequent Member
  • **
  • Posts: 293
Re: Hesitant on take-off
« Reply #10 on: February 12, 2019, 10:07:25 AM »
Hi Philo:
Sorry, dont have any first hand experience with SeaFoam.

Concerning your driveability problem, I would test your truck again and make sure it gets fully hot to see if the problem comes back. I have had an accelerator pump only go bad when it is fully hot...it worked fine when the truck was cold or just warm.

I agree with VZ that if you are not going to drive for a while, it is best to keep the tanks full...the more air you have in the tanks the more ability of the surface of the fuel to oxidize with the air. Keep the tanks full and just idle the truck to warm for a while if you cant get out on the roads. I have used Sta-Bil for a few years on all my vehicles and equipment when the ethanol was introduced and my opinion is that it is not worth the money. It is best to just run your truck at least once every 2 weeks and rebuild your carb with the new rubber seals that are designed for ethanol when that time comes.
Regards,
Henry

Offline Smokehouse

  • Newbie
  • Posts: 18
  • Newbie
Re: Hesitant on take-off
« Reply #11 on: February 12, 2019, 12:35:15 PM »
Just try to keep "real" gas in it if it's going to be parked a lot. My lawnmower starts every spring cause i put "real" gas in it. 
You are not that hot to be that bitchy.

Offline Rapid Roy

  • Frequent Member
  • **
  • Posts: 443
  • Euless, Texas
Re: Hesitant on take-off
« Reply #12 on: February 12, 2019, 01:36:46 PM »
Does that actually exist nowadays? If so, I have not found any around me.
1974 Cheyenne 10 LWB 350/TH350/AC/4 BBL Quadrajet

Online JohnnyPopper

  • Registered Users
  • *
  • Posts: 148
  • Newbie
Re: Hesitant on take-off
« Reply #13 on: February 12, 2019, 01:40:32 PM »
Last place I saw 'real' non-ethanol gas was in Oregon.

Don't try to pump it yourself, there is no Self-serve in that State.

Offline Rapid Roy

  • Frequent Member
  • **
  • Posts: 443
  • Euless, Texas
Re: Hesitant on take-off
« Reply #14 on: February 12, 2019, 05:01:41 PM »
Hard to find full service in Texas. I haven't seen one in many years. Only self service.
1974 Cheyenne 10 LWB 350/TH350/AC/4 BBL Quadrajet