1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Complex engine problem?

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Old Oct 5, 2004 | 05:14 PM
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Question Complex engine problem?

While investigating my 1k rpm rattle, I was revving the engine up and letting it go back down so i could make it go past 1k to hear the noise and see where it was coming from. After a couple of times of doing this however, the engine stay at 1500 rpm and wont go any lower. I can't find any vacuum leaks, The primary and secondary butterflies are shut. I just don't get what the hell is going on with this thing. Anyone have any ideas?
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Old Oct 5, 2004 | 06:18 PM
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I just checked out a couple of things first. it idles fine when cold, but after you gun it a couple of times it stays above 1500. Float level is fine. linkages are fine. all butterflies are closed. still cannot find vacuum leak... Need help. Has anyone ever heard of this?
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Old Oct 5, 2004 | 06:29 PM
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idle too high when warm?
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Old Oct 5, 2004 | 06:43 PM
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Just a thought, but the gas pedal isnt just sticking a bit is it?, when this happens, try pulling on the gas pedal with your foot or something and see if that helps. Ive heard of this happening a few times so maybe its your problem.
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Old Oct 5, 2004 | 08:25 PM
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Or try manually closing the throttle at the linkage and let us know if it helps.
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Old Oct 5, 2004 | 09:19 PM
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i don't have the rattle, but mine does thesame thing, usally if i've been driving for a bit, if i come to a stop and rev the gas, ocasionaly the idle will sit around 1500, then after a 30 seconds or longer it will go back to 750/800
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Old Oct 6, 2004 | 07:22 AM
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linkages are not binding and the dashpot retracts all the way.... just put in a K&N filter???? that shouldn't have affected anything.
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Old Oct 6, 2004 | 08:27 AM
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No, shouldnt affect anything unless you possibly knocked off a vacuum hose when working on it.
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Old Oct 6, 2004 | 09:51 AM
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What purpose and sequence of operation does the decel valve have. I have only a rough idea.
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Old Oct 6, 2004 | 03:54 PM
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?bump?
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Old Oct 6, 2004 | 06:13 PM
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bump jr.
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Old Oct 7, 2004 | 11:19 AM
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That Was Close.. Almost Made To The Bottom....
Bumperoony
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Old Oct 7, 2004 | 11:44 AM
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Not sure what component your speaking of. Maybe you mean the dashpot?
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Old Oct 7, 2004 | 12:05 PM
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There is a valve assebly on the side of the carb. it has a vacuum hose hooked to it and has a hose that goes up to the air filter assebly and a hose the goes down to the intake manifold.
Attached Thumbnails Complex engine problem?-valve.jpg  
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Old Oct 7, 2004 | 12:22 PM
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Thats an anti afterburn valve. Its part of the emissions system. But the vacuum source is a possible point of a leak.
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Old Oct 7, 2004 | 05:30 PM
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Do i need it? or can i yank it off without affecting drivability too much?
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Old Oct 7, 2004 | 08:48 PM
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Depends. Do you need to keep emissions on the car?
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Old Oct 7, 2004 | 09:16 PM
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no. not really concerned about the enviroment here in va beach... more concerned with tourists.
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Old Oct 8, 2004 | 05:46 AM
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Then do the emissions removal tutorial and ditch it all. Probably solve your vacuum leak as well, if thats what the problem is.
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