Register or Log In To remove these advertisements. |
|
|
|
Thread Tools | Display Modes |
07-31-2012, 09:17 PM | #1 |
Registered User
Join Date: Jul 2011
Location: Zebulon GA
Posts: 128
|
stumbling on secondaries
Hey guys, for the past couple days when I hit the gas and the secondaries open up, the truck bucks and surges real hard until I let back off. I'm thinking I have trash stuck in the secondaries. I know it's not the ignition because I just did a full tune up with cap, rotor, module, plugs and plug wires. Is there any way to clean out the secondary passages without taking the carb apart? I know the trick for cleaning the primaries where you rev it and close the choke, but I wasn't sure if there was a way to do this on the secondaries. This is my daily driver so any help is greatly appreciated!
__________________
80 K10 350 4 spd 4 Inch lift, 33 inch BFG M/t |
07-31-2012, 11:24 PM | #2 |
Drag Racer
Join Date: Nov 2006
Location: Mason City, Iowa
Posts: 1,276
|
Re: stumbling on secondaries
my truck was doing same thing and i changed fuel filter in front of carb and added a bottle of lucas complete fuel system cleaner and all is well so far
__________________
Zach Hall 1983 Chevy C10 R/T: .194 60': 2.322 330: 6.379 1/8: 9.803 MPH: 71.37 1000: 12.781 1/4: 15.314 MPH: 88.79 |
07-31-2012, 11:52 PM | #3 |
Registered User
Join Date: Jul 2011
Location: Zebulon GA
Posts: 128
|
Re: stumbling on secondaries
Will do that tomorrow, thanks!
__________________
80 K10 350 4 spd 4 Inch lift, 33 inch BFG M/t |
08-01-2012, 11:42 AM | #4 |
Registered User
Join Date: Jul 2011
Location: Zebulon GA
Posts: 128
|
Re: stumbling on secondaries
Ok, so I changed the fuel filter, but now it's doing it worse and when I hit the throttle it backfires real loud and tries to shut down. It actually did shut off once, but I got it back going. It runs great as long as I don't give it too much throttle. This is really starting to get on my nerves. We just rebuilt the carb 2 weeks ago.
Edit: it's an edelbrock 1406
__________________
80 K10 350 4 spd 4 Inch lift, 33 inch BFG M/t |
08-01-2012, 12:03 PM | #5 |
Registered User
Join Date: Oct 2011
Location: Wildomar, CA
Posts: 466
|
Re: stumbling on secondaries
Quadrajet? Check the secondary air valves (top plates) for sticking / binding, check the adjustment of the air valves (not too loose) and also check the choke pull off. One of it's jobs is to allow the secondaries to open slowly.... You can also remove the secondary hanger and rods very easily and inspect. What hanger and rods are you running? (indentification letter on the hanger and 2 letters on the rods)
|
08-01-2012, 12:13 PM | #6 |
Registered User
Join Date: Jul 2011
Location: Zebulon GA
Posts: 128
|
Re: stumbling on secondaries
It's an edelbrock 1406
__________________
80 K10 350 4 spd 4 Inch lift, 33 inch BFG M/t |
08-01-2012, 12:35 PM | #7 |
Registered User
Join Date: Jul 2009
Location: washington
Posts: 4,178
|
Re: stumbling on secondaries
Find another edelbrock on Craigslist for 75$ instead of wasting hours on this one. If it still does it with a new one you know your prob lies somewhere else
Posted via Mobile Device
__________________
377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac 3''spintech prostreet mufflers xpipe 1 3/4 headers build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217 Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511 |
08-01-2012, 12:41 PM | #8 |
Registered User
Join Date: Oct 2011
Location: Wildomar, CA
Posts: 466
|
Re: stumbling on secondaries
Ah, AKA Carter AFB. Good carb. Much better than a Holley! (anyone that knows carbs knows that)
Been years since I monkeyed with a AFB but if I recall you could also set the tension on the secondary air valves. Check the tension on the secondaries. If they open too fast you'll get a momentary lean condition (similar to a quardrajet) causing a bog and possible backfire.... |
08-01-2012, 12:48 PM | #9 | |
Registered User
Join Date: Oct 2011
Location: Wildomar, CA
Posts: 466
|
Re: stumbling on secondaries
Quote:
I work with 300+ dealerships across the country and see it almost daily.... Last edited by beamn7; 08-01-2012 at 12:58 PM. |
|
08-01-2012, 12:53 PM | #10 |
Registered User
Join Date: Jul 2011
Location: Zebulon GA
Posts: 128
|
Re: stumbling on secondaries
It was running fine for the first week or so though, what would make that change?
__________________
80 K10 350 4 spd 4 Inch lift, 33 inch BFG M/t |
08-01-2012, 12:57 PM | #11 | |
Registered User
Join Date: Jan 2010
Location: Roanoke, Tx.
Posts: 1,561
|
Re: stumbling on secondaries
Quote:
|
|
08-01-2012, 12:58 PM | #12 |
Registered User
Join Date: Oct 2011
Location: Wildomar, CA
Posts: 466
|
Re: stumbling on secondaries
Could be a piece of garbage in one of the jets, vaccum leak, timing (advance may be sticking), loose timing chain, weak valve springs, etc. Slap a gauge on it and see what you have. Should be approx 15-20in-hg and steady. Check the weights / advance....
Last edited by beamn7; 08-01-2012 at 01:07 PM. |
08-01-2012, 12:58 PM | #13 |
Registered User
Join Date: Jul 2011
Location: Zebulon GA
Posts: 128
|
Re: stumbling on secondaries
Yes, I just tuned it up because it had started missing on #8 and it hadn't been tuned up since I got it.
__________________
80 K10 350 4 spd 4 Inch lift, 33 inch BFG M/t |
08-05-2012, 01:59 AM | #14 |
Registered User
Join Date: Mar 2012
Location: elmore alabama
Posts: 9
|
Re: stumbling on secondaries
My Edelbrock HATES ethanol gas, The needles clog often and the carb stumbles badly. peace
__________________
"There's something women like about a pickup man!" Joe Diffie |
08-05-2012, 10:30 AM | #15 |
BAD BOW-Silverado XST
Join Date: May 2000
Location: Senior Member from Austin, TX
Posts: 6,431
|
Re: stumbling on secondaries
Edelbrocks have that problem due to design. The carbs put too much fuel into the intake before the engine is ready. It's reason vacuum secondaries on a qjet have a huge advantage. Fuel is not supplied until vacuum is high enough for fuel. You can probably tune to reduce it, but the WOT stumble will always be there.
|
08-05-2012, 04:05 PM | #16 | |
Registered User
Join Date: Jul 2009
Location: washington
Posts: 4,178
|
Re: stumbling on secondaries
Quote:
Sounds like it has a nasty lean surge when the secs open I it was to rich it would feel like low power at wot and get gradually stronger as airflow increases. Take it apart and spray carb cleaner into all the passages and check your float needle valves Posted via Mobile Device
__________________
377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac 3''spintech prostreet mufflers xpipe 1 3/4 headers build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217 Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511 |
|
Bookmarks |
Thread Tools | |
Display Modes | |
|
|