Carb?
Thread Starter
Racer
Joined: Apr 2002
Posts: 336
Likes: 0
From: Lafayette, Indiana
Carb?
I have a '78 L82 automatic. At WOT it runs through first and second fine. Just after shifting to third (about 70 mph) it bogs, or shuts down.
As far as I know everything is stock except I have a 14 X 2" K&N type open element air cleaner. The curb side valve cover has a breather and smog has been removed.
After the car sets a day or two I have to pump and pump and pump..........to start it. Seems to require even more pumping that others have posted about.
Time to rebuild carb? Fuel pump? Fuel filter?
As far as I know everything is stock except I have a 14 X 2" K&N type open element air cleaner. The curb side valve cover has a breather and smog has been removed.
After the car sets a day or two I have to pump and pump and pump..........to start it. Seems to require even more pumping that others have posted about.
Time to rebuild carb? Fuel pump? Fuel filter?
Burning Brakes
Joined: Aug 2000
Posts: 1,063
Likes: 0
From: Monument Colorado
Re: Carb? (Indy Year 25)
I just read in Chevy Hi-Performance that because a Quadrajet has such a small fuel bowl, sometimes a weak fuel pump can't keep up with the demand - since you're OK thru 1st and 2nd, this could make some sense.
I had the same thing. Took the carb off this weekend and put JB Weld on the infamous bowl plugs - now it fires right up after sitting all night.
After the car sets a day or two I have to pump and pump and pump..........to start it
Thread Starter
Racer
Joined: Apr 2002
Posts: 336
Likes: 0
From: Lafayette, Indiana
Re: Carb? (Tex71BB)
I had the same thing. Took the carb off this weekend and put JB Weld on the infamous bowl plugs - now it fires right up after sitting all night.
Intermediate
Joined: Jun 2002
Posts: 32
Likes: 0
From: Woodward Oklahoma
Re: Carb? (oger)
change that pump and filter! then see how it runs you won't be hurting yourself any. as I would never do a new carb without new pump and filter anyway. and if that fixes it you are done. :yesnod:
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Thread Starter
Racer
Joined: Apr 2002
Posts: 336
Likes: 0
From: Lafayette, Indiana
Re: Carb? (Rick C.)
change that pump and filter! then see how it runs you won't be hurting yourself any. as I would never do a new carb without new pump and filter anyway. and if that fixes it you are done. :yesnod:
That would be a cheap fix.
Thanks all for your comments!!
Burning Brakes
Joined: Aug 2000
Posts: 1,063
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From: Monument Colorado
Re: Carb? (Indy Year 25)
Exactly where are the bowl plugs? Is a lot of disassembly required?
Just put a dab of JB Weld on each one and you're good to go!! Good luck!
Team Owner
Joined: May 2001
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From: Exiled to Richmond, VA - Finally sold my house in Murfreesboro, TN ?? Corner of "Bumf*&k and 'You've got a purdy mouth'."
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Re: Carb? (Tex71BB)
Does it bog right as it shifts and then clears out and runs ?
Does it help if you lift the throttle right before the shift ?
If so, a weak secondary air valve spring is most likely the problem. It is letting the secondary air valve stay open when the shift occurs. As the RPM's drop, the engines need for fuel and air drop. If the valve hangs open you end up sending too much fuel and air for the motor, until the motor catches up and "clears out".
Does it help if you lift the throttle right before the shift ?
If so, a weak secondary air valve spring is most likely the problem. It is letting the secondary air valve stay open when the shift occurs. As the RPM's drop, the engines need for fuel and air drop. If the valve hangs open you end up sending too much fuel and air for the motor, until the motor catches up and "clears out".
Thread Starter
Racer
Joined: Apr 2002
Posts: 336
Likes: 0
From: Lafayette, Indiana
Re: Carb? (BSeery)
Tex71BB, thanks! The location and pic is very helpful!!!!
BSeery, it bogs down after shifting. When I let off it runs fine. I haven't pushed it after it bogs. I am usually doing a quick run up, and doing 70 in a 45 zone near my house. :eek: (It's 2 lane asphault county road that is as wide as a 4 lane hiway. ) 45 :confused:
BSeery, it bogs down after shifting. When I let off it runs fine. I haven't pushed it after it bogs. I am usually doing a quick run up, and doing 70 in a 45 zone near my house. :eek: (It's 2 lane asphault county road that is as wide as a 4 lane hiway. ) 45 :confused:
Thread Starter
Racer
Joined: Apr 2002
Posts: 336
Likes: 0
From: Lafayette, Indiana
Re: Carb? (Indy Year 25)
Well, my problem got worse. It started bogging down about 45-50.
Yesterday morning I changed the fuel filter. Took it out for a drive, and was afraid I wasn't going to get it back home. Cutting out real bad. Even died at a stop sign, and I had a hard time getting it started again.
So, I got a new fuel pump and installed it. This morning I took it for a drive. Seemed to be running better than ever. Then it started bogging down again. It seems to get worse after driving 5+ miles.
I thought maybe I had some bad gas (does that still happen) so I added half a tank of 92 octane to the 87. No help.
If I accelerate real slow I can get it up to about 60 before it cuts out. I have to leave it coast for quite a while before it will run again.
This started suddenly. I had not done anything mechanical to the car that it could be related to. I even tried switching back to my original air cleaner :nonod: . Something wore out, broke, went out of adjustment????
By the way, when I was under the car yesterday I noted that I have true dual exhaust. I was thinking it could be the cat but, there isn't one.
Any idea, suggestions? (I hate diagnostics) :confused:
Thanks for your help. I really appreciate you guys, and gals.
Yesterday morning I changed the fuel filter. Took it out for a drive, and was afraid I wasn't going to get it back home. Cutting out real bad. Even died at a stop sign, and I had a hard time getting it started again.
So, I got a new fuel pump and installed it. This morning I took it for a drive. Seemed to be running better than ever. Then it started bogging down again. It seems to get worse after driving 5+ miles.
I thought maybe I had some bad gas (does that still happen) so I added half a tank of 92 octane to the 87. No help.
If I accelerate real slow I can get it up to about 60 before it cuts out. I have to leave it coast for quite a while before it will run again.
This started suddenly. I had not done anything mechanical to the car that it could be related to. I even tried switching back to my original air cleaner :nonod: . Something wore out, broke, went out of adjustment????
By the way, when I was under the car yesterday I noted that I have true dual exhaust. I was thinking it could be the cat but, there isn't one.
Any idea, suggestions? (I hate diagnostics) :confused:
Thanks for your help. I really appreciate you guys, and gals.
Melting Slicks
Joined: May 2000
Posts: 3,280
Likes: 0
From: Virginia Beach Virginia
Re: Carb? (Indy Year 25)
I like to try the cheap fixes first. I recommend putting some fuel injection or carb cleaner in your gas tank and cruising for about 15 minutes allowing the additive to thoroughly go through the jets. Maybe there was some grime in your filter that made it to the jets and are bogging them down.
Also, I am not familiar with QJets but do they have meteriring rods? I dropped a metering rod down inside the float bowls and this really put a damper on any driving.
Also, I am not familiar with QJets but do they have meteriring rods? I dropped a metering rod down inside the float bowls and this really put a damper on any driving.
Drifting
Joined: Feb 2001
Posts: 1,603
Likes: 0
From: San Francisco, CA
Re: Carb? (VolVette)
Since it gets worse after 5 miles that may be when the engine has heated up sufficiently for the choke to pop off which make me think that for some reason the carb is starved for fuel. Since you have eliminated the fuel pump and filter and it happened suddenly, consider rebuilding the carb.
Thread Starter
Racer
Joined: Apr 2002
Posts: 336
Likes: 0
From: Lafayette, Indiana
Re: Carb? (VolVette)
VolVette, I think I'll try the carb cleaner. Can't hurt.
I don't know anything about Q-jets either.
R. Bruno, I guess if the carb cleaner has no effect the rebiuld is next.
When I got the fuel pump at Autozone they said if the filter and screen were not changed at the same time, the warantee on the pump was void. Is there a "screen" on my 78? If so, where is it?
I don't know anything about Q-jets either.
R. Bruno, I guess if the carb cleaner has no effect the rebiuld is next.
When I got the fuel pump at Autozone they said if the filter and screen were not changed at the same time, the warantee on the pump was void. Is there a "screen" on my 78? If so, where is it?
Le Mans Master
Joined: Mar 2002
Posts: 7,456
Likes: 2
From: Coming home from Luckenbach Texas
Re: Carb? (Indy Year 25)
Also make sure your fuel lines aren't pinched anywhere. Especially the rubber hoses from the pump going back to the top of the frame.
But methinks you're going to need to rebuild/replace the carb. It's probably a good thing to do anyway! :yesnod:
But methinks you're going to need to rebuild/replace the carb. It's probably a good thing to do anyway! :yesnod:
