Car bucks at WOT
Thread Starter
Instructor
Joined: Apr 2004
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From: St Paul MN
Car bucks at WOT
When I driving my car if I floor it, the car will start to take off nice, then it will just cut out, then go, cut out, go, cut out, until I let my foot off the gas. What would be the cause of this? I have a stock '76 L-82 with a quadrajet.
Race Director
Joined: Dec 1999
Posts: 11,096
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From: Sierra Foothills CA
It sounds like your secondaries are opening & closing under WOT. Many, many years ago I had this problem w/ my Q-jet right before I shelved it for a Holley. If you look at an exploded view I hope this will make sense. There's a small piston that's held in place by a thin hook-like wire. If I remember right this plays a part in secondary function. I found later that the shop that did the custom mods on my carb had left out the wire piece & that appeared to be my problem. Maybe Lars can chime in to clarify this. If you're lucky it may just be that you need to adjust the spring tension that controls the opening rate- that wasn't the case for me. Good luck.
Last edited by Les; Apr 4, 2005 at 10:56 AM.
Melting Slicks
Joined: Nov 2001
Posts: 2,668
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From: Eastern US XX
Originally Posted by crazydalys
When I driving my car if I floor it, the car will start to take off nice, then it will just cut out, then go, cut out, go, cut out, until I let my foot off the gas. What would be the cause of this? I have a stock '76 L-82 with a quadrajet.
Drifting
Joined: Sep 2004
Posts: 1,532
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From: Fairview Heights Illinois, near Saint Louis MO, STL C3 Shark
Originally Posted by crazydalys
I just replaced the fuel filter, it idles better, but this problem persists. 
Maybe it's that spring?
Maybe it's that spring?
Tech Contributor
Joined: Aug 1999
Posts: 15,177
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From: Connecticut, USA
Also check to see if you still have the "S" hoses to the fuel pump or just fuel line. I had this happen once with regular fuel line and it kinked and starved the carb at WOT.
Gary
Gary
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Thread Starter
Instructor
Joined: Apr 2004
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From: St Paul MN
Originally Posted by ruby76
Do you have the little fuel filter built in to the qjet, or an aftermarket in-line filter? This is exactly what my 68 truck did with a dirty fuel filter. Unless your distributer or something is not giving spark at WOT. I dunno.
Thread Starter
Instructor
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From: St Paul MN
secondary windup spring
I'll have to try adjusting the secondary wind up spring. I see from previous posts it's on the passenger side of the carb. Does anyone have a picture of it's location they could post?
Thread Starter
Instructor
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From: St Paul MN
Originally Posted by gtr1999
Also check to see if you still have the "S" hoses to the fuel pump or just fuel line. I had this happen once with regular fuel line and it kinked and starved the carb at WOT.
Gary
Gary
Le Mans Master
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From: B'Ville NY
Cruise-In III Veteran
St. Jude Donor '05
Originally Posted by gtr1999
Also check to see if you still have the "S" hoses to the fuel pump or just fuel line. I had this happen once with regular fuel line and it kinked and starved the carb at WOT.
Gary
Gary
Team Owner
Joined: Jul 1999
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From: Huntersville NC
Originally Posted by crazydalys
I'll have to try adjusting the secondary wind up spring. I see from previous posts it's on the passenger side of the carb. Does anyone have a picture of it's location they could post?
There have been pics posted for this spring adjustment, but sorry I don't know where the pics are! It is real easy with a pic, but might be hard to figure out otherwise. You have to loosen an allenhead screw from underneath and then at the same time turn the adjustment screw from above.
Burning Brakes
Joined: Sep 2004
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From: Vernon British Columbia
St. Jude Donor '05
First C3 General Poster!
I had a problem like that in the Cutlass on its first engine, and it wasnt the carb at all, it was the distributor getting grounded to the engine and the spark wasnt generating properly. Check that out if youre carb turns out to be fine.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
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From: At my Bar drinking and wrenching in Lafayette Colorado
Sounds like fuel starvation at WOT - you're going lean. Causes include:
1. Low float level
2. Dirty filter
3. Kinked rubber fuel line either back at the tank or at the forward frame rail
4. More than 1 fuel filter installed (in-line filter somewhere in the system in addition to the in-carb filter)
5. Dirty tank pick-up sock
6. Poor fuel pressure (bad fuel pump)
7. Incorrect secondary metering rods (too fat)
8. Incorrect secondary airvalve spring windup (should be at 3/4 turn) - loose spring will cause lean secondary operation
Lars
1. Low float level
2. Dirty filter
3. Kinked rubber fuel line either back at the tank or at the forward frame rail
4. More than 1 fuel filter installed (in-line filter somewhere in the system in addition to the in-carb filter)
5. Dirty tank pick-up sock
6. Poor fuel pressure (bad fuel pump)
7. Incorrect secondary metering rods (too fat)
8. Incorrect secondary airvalve spring windup (should be at 3/4 turn) - loose spring will cause lean secondary operation
Lars
Thread Starter
Instructor
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From: St Paul MN
Originally Posted by lars
Sounds like fuel starvation at WOT - you're going lean. Causes include:
1. Low float level
2. Dirty filter
3. Kinked rubber fuel line either back at the tank or at the forward frame rail
4. More than 1 fuel filter installed (in-line filter somewhere in the system in addition to the in-carb filter)
5. Dirty tank pick-up sock
6. Poor fuel pressure (bad fuel pump)
7. Incorrect secondary metering rods (too fat)
8. Incorrect secondary airvalve spring windup (should be at 3/4 turn) - loose spring will cause lean secondary operation
Lars
1. Low float level
2. Dirty filter
3. Kinked rubber fuel line either back at the tank or at the forward frame rail
4. More than 1 fuel filter installed (in-line filter somewhere in the system in addition to the in-carb filter)
5. Dirty tank pick-up sock
6. Poor fuel pressure (bad fuel pump)
7. Incorrect secondary metering rods (too fat)
8. Incorrect secondary airvalve spring windup (should be at 3/4 turn) - loose spring will cause lean secondary operation
Lars
Wow, well I know it's not 2 or 4. Sometimes it'll be running fine, then I'll fill up the gas tank and the symptons will start again.
