![]() |
Register or Log In To remove these advertisements. |
|
|
![]() |
|
Thread Tools | Display Modes |
|
![]() |
#1 |
Registered User
Join Date: Oct 2006
Location: Austin Texas
Posts: 60
|
idols great, sputters and pops when I give it gas
I have a 72 chevy 350 just recently tuned it up, points, plugs, duell at 30 timing 8degrees top dead center. adjusted carb was real rich.... three turns in....
Now I have a significant problem, truck will start, idol but when i give it gas it stalls or pops back thru carb, and sometimes it doesnt do it at all. any ideas? is it carb or is it something else, vaccum advance is working good. please help! battery was low on water, I know old battery could a bad battery have something to do with it??? Last edited by C203/4; 01-05-2008 at 10:08 AM. |
![]() |
![]() |
![]() |
#2 |
Senior Member
![]() Join Date: Jul 2005
Location: MISSOURI
Posts: 3,256
|
Re: idols great, sputters and pops when I give it gas
water in fuel ? point gap too close? starving for fuel? X plug wire? Change fuel filter?
__________________
The biggest problem people have, is other people Thou shalt be cool and not hassle ![]() Be a site supporter. ![]() The heart of the wise inclines to the right, but the heart of the fool inclines to the left." Ecclesiastes 10:2 |
![]() |
![]() |
![]() |
#3 |
Registered User
Join Date: Oct 2006
Location: Austin Texas
Posts: 60
|
Re: idols great, sputters and pops when I give it gas
nope no water in fuel, how do i check point gap? see if ti still is at duell of 30? plug wires are good havent changed fuel filter... would any of these make it run good one day and not the next?
|
![]() |
![]() |
![]() |
#4 |
Registered User
Join Date: Sep 2007
Location: jackson MO
Posts: 143
|
Re: idols great, sputters and pops when I give it gas
You may want to check the accelerator pump on the carb. If it was idling rich, then you leaned it out the rich idle could have been hiding a poor pump shot.
|
![]() |
![]() |
![]() |
#5 | |
Senior Member
![]() Join Date: Sep 2005
Location: Lewisville, Nc
Posts: 10,234
|
Re: idols great, sputters and pops when I give it gas
Quote:
![]()
__________________
David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube |
|
![]() |
![]() |
![]() |
#6 |
Registered User
Join Date: Jun 2007
Location: Smyrna, GA
Posts: 709
|
Re: idols great, sputters and pops when I give it gas
I had a bad battery in my truck and it gave me a similar problem, but I did not have any backfire / pop... my truck just would not stay fired. I did not know this but the battery acts like a huge fuse and take all the extra voltage that your ignition is cranking out. May not be your problem, but something to consider. Hope this helps-
__________________
Rottenwood Garage 1970...71...72 C1500 aka Orange aka Sideshow Bob 540 BB Straub Roller Cam, AFR Magnums, XP 950, TKO 600 2 Tons of Fun |
![]() |
![]() |
![]() |
#7 |
Registered User
Join Date: Oct 2006
Location: Austin Texas
Posts: 60
|
Re: idols great, sputters and pops when I give it gas
so maybe i should turn the screw back out... and try that ?
|
![]() |
![]() |
![]() |
#8 |
Registered User
Join Date: Jun 2002
Location: Knoxville Tenn.
Posts: 3,058
|
Re: idols great, sputters and pops when I give it gas
Turn the mixture screws all the in (lightly). Turn each one back out 3and 1/2 turns. 8* BTDC-right?
__________________
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 |
![]() |
![]() |
![]() |
#9 |
Senior Member
Join Date: Nov 2005
Location: northwestern wi
Posts: 2,111
|
Re: idols great, sputters and pops when I give it gas
take theair cleaner of with engine off look in top of carb while opening throtel to see if accelerator pump is giving it a good shot of fuel. do not try to start it with the air cleaner off, there is no need to burn it yet
__________________
common sense isn't so common anymore |
![]() |
![]() |
![]() |
#10 |
Account Suspended
Join Date: Jul 2006
Location: DFW
Posts: 1,427
|
Re: idols great, sputters and pops when I give it gas
How did it run before the tuneup? If it ran better, its something you changed during the tuneup.
I'd guess dwell, timing, or carb adjustment. Run it at night or in the dark and look for spark where it doesn't belong. The idle mixture screws are/were at "3 turns in?" Seems like a lot since a fairly typical starting point is 1.5 turns out from where the bottom. Setting the dwell will set the point gap. Is the timing 8 degrees advanced, or retarded? Should be advanced and I can't even say if it would or wouldn't idle that retarded... |
![]() |
![]() |
![]() |
#11 |
Registered User
Join Date: Oct 2006
Location: Austin Texas
Posts: 60
|
Re: idols great, sputters and pops when I give it gas
Well, tried turning the screws out more, will check dewell again, could i just have received a bad set of points?
|
![]() |
![]() |
![]() |
#12 |
Msgt USAF Ret
![]() ![]() Join Date: Jan 2005
Location: Kalamazoo, Michigan
Posts: 8,714
|
Re: idols great, sputters and pops when I give it gas
Good advice from all. Popping back through the intake is almost always a lean condition, or timing too far advanced. Rarely a bad or incorrectly set intake valve will cause it. Compression test or leakdown test is a good diagnosis for that.
Setting dwell will change the static timing, as the points are opened the timing will be advanced. The dwell should be set first and then the static timing. Here is a good tutorial on points and ignition . http://abbysenior.com/mechanics/ignition.htm
__________________
VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative. |
![]() |
![]() |
![]() |
#13 |
Registered User
Join Date: Feb 2006
Location: Smyrna, Ga
Posts: 1,647
|
Re: idols great, sputters and pops when I give it gas
check all your wires too. i have had similar problems when i had a burnt wire.
make sure that the wires arent damaged around your exhaust manifolds. if there is a bad wire the engine will appear to idle fine, but when you rev it up that cylinder will be backfiring. also when you adjusted the carb you said you adjusted to three turns in. i am not sure what that means or what carb you have. but you should turn the screws in until they are lightly seated and then back them out to their proper setting. good luck |
![]() |
![]() |
![]() |
#14 |
Registered User
Join Date: Mar 2006
Location: Kansas
Posts: 865
|
Re: idols great, sputters and pops when I give it gas
Also check the distributer cap for tracking. If you improved spark it might have started a prob.
|
![]() |
![]() |
![]() |
#15 |
Rollin 16's son!
Join Date: Nov 2007
Location: Logan, UT
Posts: 65
|
Re: idols great, sputters and pops when I give it gas
I'd suggest converting to HEI... In that situation it's better to be "pointless".
And like 72lb4x4 said about looking for spark and what not... But don't look too hard, I've seen a guy lose all his facial hair from that. |
![]() |
![]() |
![]() |
#16 |
Account Suspended
Join Date: Jul 2006
Location: DFW
Posts: 1,427
|
Re: idols great, sputters and pops when I give it gas
Heh! I only suggested opening the hood in the dark and looking for stray arcs--I did't say rub his face on the wires...
I also asked when the problem started and got no answer ![]() |
![]() |
![]() |
![]() |
#17 |
Registered User
Join Date: Oct 2006
Location: Austin Texas
Posts: 60
|
Re: idols great, sputters and pops when I give it gas
yea started after a tune up and my father adjusted the carb ' was a mechanic untill the early 90's and had his own tune up business...
|
![]() |
![]() |
![]() |
#18 |
Registered User
Join Date: Jan 2001
Location: Queen Creek, Arizona
Posts: 1,626
|
Re: idols great, sputters and pops when I give it gas
Holy crap! I've got the exct same problem on my 71, just had the carb rebuilt and it is acting the same. According to 2 different mechanics it could be the "_____ valley" or " ____ tube" ( I forget what they called it)under the intake manifold that warms up the carb/choke is plugged and cannot heat it, therefore the choke is always on. Not an issue during summer months, just when its cold? Also, timing chain could be an issue as well. Hope that helps, just F.Y. I. local shop wants $400. to remove, clean and re-install the manifold which seems like date rape to me!
__________________
Dave aka "Wild" Current truck "Ida Mae" 71 K5 Blazer Former Trucks "Loretta" 71 Longbed (AZ) "Tanya" 69 Stepside (AZ) "Ferdinand" 71 Longhorn (SD) "Patches" 67 Panel (IA/ KY) "Rosita" 68 C30 (KY) Instagram @Wildforwheels @k5_klub @c10university Profile pic provided by Jeff Sundance |
![]() |
![]() |
![]() |
Bookmarks |
Thread Tools | |
Display Modes | |
|
|