1982 GMC S15 carburetor

BRUCE MORGAN

MEMBER
1982 GMC S15
4 CYL
2WD
MANUAL
114,000 MILES

I have an 82 s15 1.9l and sometimes it runs rough and backfires. I noticed that the exhaust pipe from the manifold gets red hot (cut out cat and muffler thinking one may be clogged) it used to only do it when it was cold and if I kicked the gas peddel and shut off the truck it would go away. Now it does it all the time. I shot carb cleaner through it and on it looking for vac leaks but didn't find any.

5 Replies

JDL

MECHANIC
16,098 POSTS

How long since a tune-up? Does the carb choke work like it should? How about timing?

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Saturday, February 21st, 2009 AT 12:08 PM

BRUCE MORGAN

MEMBER
3 POSTS

New plugs wires cap rotor timing at 6 deg btdc all thiat checks out it seems like it's something in the carburetor. It would go into high idle and come out when I kicked it down but it started this running rough backfiring and missing but if I either turned it off or kept kicking the gas it would finally stop. Well thats not working now.

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Saturday, February 21st, 2009 AT 1:54 PM

JDL

MECHANIC
16,098 POSTS

If you think it is the carb, maybe it needs a carb kit? The backfiring makes me wonder about a valve issue?

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Saturday, February 21st, 2009 AT 2:50 PM

BRUCE MORGAN

MEMBER
3 POSTS

Sohc? I don't know much about these motors. Would a sticking valve make the exh pipe red hot? I mean litterally glowing red. If valve was sticking I wouldn't hear it on an ohc motor right?

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Saturday, February 21st, 2009 AT 5:46 PM

JDL