LS1 First Fire Idle Speed Too High
10-30-2013, 03:28 PM
#1
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LS1 First Fire Idle Speed Too High Hello All,
I joined to get some help with my 2008 Silverado 5.3L LC9 Swap into a 1979 Camaro. Rear End 10 Bolt 8.5" ring gear 2.41:1 Positraction. Tranny: 4 Speed Muncie. Holley 750 Vacuum Secondary 3310-3. MSD ignition 6012. Manifold Edelbrock 71187.
Currently having trouble with first fire idle way to high. When I adjust idle speed screw it does nothing.
How do I replace/repair idle speed screw function?
Looking forward to LS1 Tech.
-Kyle
I joined to get some help with my 2008 Silverado 5.3L LC9 Swap into a 1979 Camaro. Rear End 10 Bolt 8.5" ring gear 2.41:1 Positraction. Tranny: 4 Speed Muncie. Holley 750 Vacuum Secondary 3310-3. MSD ignition 6012. Manifold Edelbrock 71187.
Currently having trouble with first fire idle way to high. When I adjust idle speed screw it does nothing.
How do I replace/repair idle speed screw function?
Looking forward to LS1 Tech.
-Kyle
Last edited by 79CamaroKyle; 10-31-2013 at 02:56 PM.
10-31-2013, 05:12 AM
#4
It should be a simple matter to look at the idle speed screw and butterflies and see if something is hanging up or sticking. There is also a screw to adjust the secondaries, but you need to get to it from underside the carb.
If that is all good and you don't have vac leaks, then you can back off the idle timing to lower the idle speed. That is what I had to do with mine.
If that is all good and you don't have vac leaks, then you can back off the idle timing to lower the idle speed. That is what I had to do with mine.
10-31-2013, 07:59 AM
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I ordered some vacuum plugs. I have two open ports on the bottom side of the Holley and one on the driver side head. I'll plug them and report back.
The Holley is about 25 years old handed down so it may need a major overhaul. I f plugging the vacuum holes does not work I will pull it out and close off the secondary completely to see if that is causing it.
Thanks for the help!
-Kyle
The Holley is about 25 years old handed down so it may need a major overhaul. I f plugging the vacuum holes does not work I will pull it out and close off the secondary completely to see if that is causing it.
Thanks for the help!
-Kyle
10-31-2013, 02:59 PM
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I have a bunch of pictures posted at this link:
https://www.facebook.com/media/set/?...1&l=1d648a0113
First Fire Youtube:
Video of Idle Choke Closed:
https://www.facebook.com/media/set/?...1&l=1d648a0113
First Fire Youtube:
Video of Idle Choke Closed:
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10-31-2013, 07:14 PM
#9
Why do you have your hoses ran backwards on the radiator??? Don't see a return spring on the carb??? Ive always had to run one, or they don't go back to home position
Last edited by snook; 10-31-2013 at 07:34 PM.
11-01-2013, 01:25 PM
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As for the spring, definitely need to get one on there. This carb is from the early 80's and I've had nothing but problems with it so far.
11-01-2013, 05:18 PM
#11
I thought there might have been a trick I didn't know with the hoses, just wondering. Is it still idling high? Next time it does that, see if it will close by hand anymore
11-01-2013, 10:01 PM
#12
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Take the vac. secondary holley and throw it in the garbage and get you a good holley mechanical secondary carb, 750 double pumper, simple and easy to tune, you will thank me later.