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low idle

Discussion in 'The Garage' started by larsfrog, Jul 12, 2004.

  1. larsfrog

    larsfrog Registered Member

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    My 86 305 was idling fine a few days ago, then all of a sudden it dropped about 150 RPM's. I checked the PCV valve (by rattling it) and grommet (I replaced it), I believe my EGR valve is OK but not sure (how do you check that?, the vacuum to it is good), I believe my TVS is good but did not get any vacuum/pressure (I do not know which one) to/from my carbuerator (should there have been)? I checked the fuel vapor canister line which leads to my TVS and there was no pressure there, should there be? I am banging my head against the wall becuse I have checked all of my vacuum lines a bunch of times and still can not figure it out. Is it something as easy as turning up my idle, I counted that one out because it does not make sense for the idle to change that much in one fail swoop.
     
  2. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    What was the weather like a few days ago ? Mine will do that sometimes for no reason sometimes , and the only difference is the outside temp and humidity ( it never drops too low , but I keep it around 550-600 in gear ). If that 305 is carbed , you need to adjust it peiodically ,no way around it /forums/images/graemlins/k5.gif
     
  3. larsfrog

    larsfrog Registered Member

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    isn't 550 on the close side to stalling? Mine is running 550-600 in gear right now and it shakes pretty good, also when I switch from drive to reverse it does not stall but seems as if it gets close. The manual says that idle should be @650 just trying to keep up with the specs. The humidity decreased noticebly the last couple of days, is that consistant with yours? Does yours fluctuate from 650-550 often, if not how much does your fluctuate?
     
  4. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Mine runs nice and smooth with a slight normal chevy tick. It doesn't stall out. I like it closer to 650 in gear but when it gets bad it still works well enough I can be lazy and let it be , even wheel with it . You want cool air with not too much moisture . I just checked and you have 68 percent humidity right now, which is funny because I didn't see any rain in your area . Mine runs best when humidity is low and temps are down . /forums/images/graemlins/k5.gif

    Now your combo may be a bit different due to variations of parts . If you want just raise the idle up a little . The best way is to adjust the mixture screws in until it wants to stall, then back out until it smooths /forums/images/graemlins/k5.gif
     
  5. larsfrog

    larsfrog Registered Member

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    I have never adjusted them before, do I do adjust one until the car wants to stall then do the same for the other? They are located near the base of the carbuerator in the front right?
     
  6. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Yes , you do one side at a time, probably several times until you get it right. They are on each side on the baseplate at the front. There may be caps on them that you can remove ( usually gone after first tune up ) , a screwdriver won't fit these, you can get the tool at Napa and places like that , or like I used to before tool , is to go through all your 1/4 inch sockets until you find one that fits the hole while still going over and grabbing the adjuster screw head . Don't be worried , just keep going in and out slowly until it sounds right , its something that will come easy after awhile . /forums/images/graemlins/k5.gif
     
  7. larsfrog

    larsfrog Registered Member

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    After driving a bit my idle is ~650 like it should be, but when I shut off my car and then restart that is when it drops to ~600-550. This did not seem to happen a few days ago, is this normal or not. If not what could be wrong? I do not want to change my idle mixture just yet, I want to see what you guys think
     
  8. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    I forgot to ask if you run A/C or not, and a choke. Could just be fine after it warms up. And if you run A/C thier should be a solenoid to bump up the idle . If it stays fine warm when driving, you should be ok. /forums/images/graemlins/k5.gif
     
  9. larsfrog

    larsfrog Registered Member

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    I was wrong when I posted those RPM's above (~550-600), after I shut off the engine and restart it hovers from 450-500. But when I drive my car a short distance it idles @600 even if I put it in park then back to drive it stays @600. I do have a choke and I do have A/C do you think that one of those may be off or not functioning (solenoid)? I know this is not a big deal because my car runs but it is just odd that this all of a sudden happened. I feel as if it is something that is malfunctioning
     

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