Chevy carburetor problems
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Fleet Mechanic
Joined: Jul 2004
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From: Travelers Rest SC
Chevy carburetor problems
Serves me right for buying a Chevy; my '85 S10 has been developing a carburetor problem (I think). It's an '85 2.8 V-6, and after 5 minutes or so of driving, it won't take any throttle. If you give it any gas, it wants to die. Problem is- I have a hill to climb every morning! It seems like after it's really warmed up (or stone cold) the problem goes away. I assume it's the carb. I was going to pick up a carb kit and clean it this weekend. Any suggestions? I haven't had any luck finding a decent Chevy forum; all they talk about is making trucks lower and lower! Why not just buy a car and be done with it?
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From: Sarnia, Ontario, CANADA!
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Postmaster
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From: Durham, NC
Originally Posted by Beast12
Actually, you are right. The only person who wasn't much help was Eric (Torque1st). 
-Matt
-Matt
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Post Fiend
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From: Atlanta GA
> I was going to pick up a carb kit and clean it this weekend. Any suggestions?
Don't bother if the TPS switch is in the carb. It is not a carb easily rebuilt. Get a good repair manual (Haynes) and find out what is really wrong. If it is the carb/TPS switch then suck it up and spend the money on either a new Holley or rebuilt carb ($300).
You can try to replace the TPS switch and do the carb rebuild, the results will most likely be a "loose" carb that needs rebuilding after you "refurbed" it. Just time and money lost on a 20 year old mechanical piece of junk that never worked right even new.
If you do not need emissions then go with the plain and simple HEI dist and standard carb without CPU/feedback controlled functions.
Don't bother if the TPS switch is in the carb. It is not a carb easily rebuilt. Get a good repair manual (Haynes) and find out what is really wrong. If it is the carb/TPS switch then suck it up and spend the money on either a new Holley or rebuilt carb ($300).
You can try to replace the TPS switch and do the carb rebuild, the results will most likely be a "loose" carb that needs rebuilding after you "refurbed" it. Just time and money lost on a 20 year old mechanical piece of junk that never worked right even new.
If you do not need emissions then go with the plain and simple HEI dist and standard carb without CPU/feedback controlled functions.
i ain't rite
Joined: Mar 2005
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From: Marlboro Mental Hospital.
i think 1 well placed shot with an armor piercing round, fired from a 50 cal. B.A.R. should fix it nicely.
i agree with rebocaro. drop a regular carb and hei dist in it, and you are done.
i agree with rebocaro. drop a regular carb and hei dist in it, and you are done.
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Fleet Mechanic
Joined: Jul 2004
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From: Travelers Rest SC
I actually have a 302 sittin' around doing nothing... seriously, though, what carb should I look for? I'd be happy to put some technology under the hood that I can understand. Is there a Holley that would bolt on? What car would I get an HEI out of? I realize I deserve all the ribbing I get, but I need to get a few months out of this before I can shop for a proper FORD truck.
Last edited by Beast12; Mar 25, 2006 at 04:25 PM. Reason: removed "POS"
Fleet Owner
Joined: Aug 2001
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From: Drummonds, TN USA
I'm assuming we're dealing with a carb, not an EFI system.
It runs right once it warms up.
The carb system that is at fault should be the choke positioner.
possibilities are:
1) It is not opening smoothly.
2) It is out of adjustment period.
3) If it has a vacuum dashpot it may be holed and non-functioning.
- I would check the vacuum devices first by drawing on them with a clean piece of vacuum line. You should not be able to suck a constant flow of air through them.
Most chokes are set up to be slammed closed at first, but the vacuum dashpot responds to engine vacuum once it begins to run. Soon as the engine fires, the dashpot pulls the choke open. After a certain point the choke is opened by other means.
This system was used on Chevvies all the way back to the sixties that I know for sure.
Testing and setting your choke is a better first step than immediately grabbing a rebuild kit or trashing the OEM carbuerettor. The price is nicer too...
NOTE: You may also have a vacuum leak somewhere.
It runs right once it warms up.
The carb system that is at fault should be the choke positioner.
possibilities are:
1) It is not opening smoothly.
2) It is out of adjustment period.
3) If it has a vacuum dashpot it may be holed and non-functioning.
- I would check the vacuum devices first by drawing on them with a clean piece of vacuum line. You should not be able to suck a constant flow of air through them.
Most chokes are set up to be slammed closed at first, but the vacuum dashpot responds to engine vacuum once it begins to run. Soon as the engine fires, the dashpot pulls the choke open. After a certain point the choke is opened by other means.
This system was used on Chevvies all the way back to the sixties that I know for sure.
Testing and setting your choke is a better first step than immediately grabbing a rebuild kit or trashing the OEM carbuerettor. The price is nicer too...
NOTE: You may also have a vacuum leak somewhere.
Last edited by Greywolf; Mar 25, 2006 at 03:57 PM.
Junior User
Joined: Nov 2002
Posts: 77
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From: Mooretown Canada
Just a thought here, but have you checked out your egr valve. I drive a 83 buick regal in the winter with a 305, so i have had my fair share of troublehooting. A while back, my car would start up and run fine for the first few minutes, then she would idle rough and hesitate when i gave it gas. Sometimes it would just stall on me. Now it only did this after it warmed up because the egr does not get vacum until its warm (I beleive thats what i read). After i switched egr valves it ran fine, So you may want to check that out.
The other thing is the flapper door on your aircleaner snorkel that shuts of clean, cool airflow while warming up. Instead taking in warm air from the exhaust manifold. Sometimes the vaccum motor, or the temp sensor in the aircleaner malfunction, leaving the little flap closed the whole way. This affects your power, and in my experice,I stalled at every stop. After 10 minutes or so that flap should be opened. If not, stick a clothes pin in there.
And in general a checkover of all your vacum lines would be beneficial.
Now these are just my expereiences, take it as you will, i could be wrong.
Rod
The other thing is the flapper door on your aircleaner snorkel that shuts of clean, cool airflow while warming up. Instead taking in warm air from the exhaust manifold. Sometimes the vaccum motor, or the temp sensor in the aircleaner malfunction, leaving the little flap closed the whole way. This affects your power, and in my experice,I stalled at every stop. After 10 minutes or so that flap should be opened. If not, stick a clothes pin in there.
And in general a checkover of all your vacum lines would be beneficial.
Now these are just my expereiences, take it as you will, i could be wrong.
Rod
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Fleet Mechanic
Joined: Jul 2004
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From: Travelers Rest SC
I looked at it a bit yesterday, and noticed that many of the thousands of vacuum lines do indeed seem to be cracked. I guess I'll buy some vacuum hose, and start replacing them one by one. Then I can do some vacuum tests as well. It is a very complicated carb (last year before EFI), so I'm not optimistic, as I don't understand the function of all the various doo-dads and gizmos hanging off of it.
Junior User
Joined: Nov 2002
Posts: 77
Likes: 0
From: Mooretown Canada
I would suggest, if you haven't yet, go and get a Haynes manual for your truck. It will give you some insight to all the emission control aspects of the chevy system. Its alot easier to troubleshoot when you understand the function of parts and when they are to operate. The Haynes manual is a useful resource, it also has a troubleshooting section.