now it idles too low
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now it idles too low
my truck was idling too high and running a little rich, so somebody suggested that i should hook up the electric choke. it has a holley 670 street avenger on it, but i never hooked up the choke. i hooked it up yesterday. the choke seems to operate properly. it idles about 1600 cold. once it heats up, though, it idles around 400-500. it idles so low it sounds like it wants to cut off. now, if i stomp the gas, when it comes back down it just cuts off. i can ease into the gas and back off and it's fine. it does have a Comp Cams cam in it, but i don't know a whole lot about it. i have the build sheet on the motor with cam specs if that will help anybody. should i just take the choke back off? it idles really high that way, but at least it doesn't cut off. it sounds really good idling, but it wants to cut off after giving it gas (quickly). any ideas?
thanks!
thanks!
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i tried that. if you mean the spring-loaded screw between the throttle linkage and the secondary fuel bowl. i tightened it all the way down and loosened it all the way back out and nothing changed. i also tried tweaking the a/f mixture screws on each side. nothing changed with those either.
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not familiar with your carb, but there should be on there whats called an idle cam.
basically, as the choke heats up, it'll rotate and the throttle will have 2 screws that rest on various parts of this cam.
when teh choke heats up all the way, it'll turn the cam all the way, and one of the screws, called the curb idle or warm idle screw, should rest against the lowest point of the cam OR against the carb body itself. If you turn this screw, it'll actually move the throttle resting position, and thus, raise or lower the idle speed.
basically, as the choke heats up, it'll rotate and the throttle will have 2 screws that rest on various parts of this cam.
when teh choke heats up all the way, it'll turn the cam all the way, and one of the screws, called the curb idle or warm idle screw, should rest against the lowest point of the cam OR against the carb body itself. If you turn this screw, it'll actually move the throttle resting position, and thus, raise or lower the idle speed.
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awesome. makes sense. now where should that screw be? also, the rpms don't actually come down from fast idle until i give it gas and let back off. then it settles down to where it sits. do you agree that 400-500 rpm is too low? why does it cut off when i stomp it and let off? sorry for all the questions...never really played with a carb that much.
thanks!
thanks!
Postmaster
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I think 600 is an ideal idle, but that's if it's running very good, higher if it misses, etc.
Higher also if an automatic.
You can find the idle speed screw by watching the throttle linkage as it moves. Do this when engine is fully warmed. What makes the linkage come back and stop where it does is because the tip of the screw runs into the carb body. You can turn that screw to adjust the idle speed.
Higher also if an automatic.
You can find the idle speed screw by watching the throttle linkage as it moves. Do this when engine is fully warmed. What makes the linkage come back and stop where it does is because the tip of the screw runs into the carb body. You can turn that screw to adjust the idle speed.
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From: Brentwood,CA
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i'm not sure what your talking about, 390. four corner? i know there are adjustment screws on both sides in the front, but i didn't see any in the back. this is the carb i have, if this helps any.
http://www.holley.com/products.asp?product=0-80670
thanks!
http://www.holley.com/products.asp?product=0-80670
thanks!
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From: Illinois
This shows all the adjustments for your carb: http://www.holley.com/data/Products/...99R10219-3.pdfIf your engine is idling too low, the cutting out problem is probably a result of that. But, it could be a problem with the accelerator pump. With the choke fully open, look down the throat of the carb and push the throttle down. You should see two strong streams of gas being shot into the bore. I would suggest doing this with the engine off. Otherwise, a lean backfire could give you a quick haircut!
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good point. i did check that already though, and gas is shooting in fine. 2 strong streams, just like you said.
could it be possible that the curb idle adjustment screw is too short? what if i just got a longer screw to put in there? if i'm way out there, feel free to shoot me down.
could it be possible that the curb idle adjustment screw is too short? what if i just got a longer screw to put in there? if i'm way out there, feel free to shoot me down.
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From: Illinois
Originally Posted by jbirdsvt
could it be possible that the curb idle adjustment screw is too short? what if i just got a longer screw to put in there? if i'm way out there, feel free to shoot me down.
Good luck and let us know how you do!
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i took the screw completely out and turns out that the little spring was binding up somehow. i turned the spring around a little and paid more attention to it when i put it back in and VOILA!! now it works like it's supposed to. thanks for all your help fellas