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I do have IAC, I would hesitate to mess with my throttle plates... mine has an idle set screw just like a carb. the issue I run into is that the tiniest adjustment on the idle set screw can cause a significant jump in RPM...
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I was the same way, took me a few times to get it right but was worth it. I went from idling at 1100 to 850. There probally is a step by step how to somewhere on how to do it.
68 Half cab
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what do you mean you adjusted your throttle plates?
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yeah... ive done that twice... for whatever reason, when you get the idle close to 800, it starts getting real touchy... vacuum leak touchy... but there are no vacuum leaks... when I get to 800 it suddenly jumps to 1100 and to get it back down you have to almost completely unscrew and then it drops to 500 or less... I think I am going to set it next time with the dizzy vac line unhooked and plugged...
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yep... gonna mess with it tonight. weather got too bad here last night to stand being outside...
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so I tuned the idle tonight and everything is working really well. nice consistent idle at 850, 13.54 AFR. my only concern is that now the AFR correction is really high at idle. after some research, the tuning/troubleshooting guide points to the only unknown in my engine; the cam. I did my baseline tune based on the assumption of a mild cam (duration of 210-230 at .050 lift). this was a guess as the cam was in the motor when I got it form NCSUBRONC here on the board, and sounds very lopey. i'm thinking now this cam is pretty hot (230 plus). my vacuum at idle is low ~9-10 inches, my AFR set point and AFR actual won't line up, and the correction is over 25%. the troubleshooting guide says this can be caused by 3 things, low fuel pressure, engine not at operating temp, or improper camshaft selection. since i know the other two are good, I assume my camshaft selection was wrong. gonna call edelbrock tomorrow to see how to change the cam profile in the tuner (guide says to do it in the initial setup procedures, but says reloading initial setup is not necessary in another portion... ? anyway, that's what I did to the bronco today :/
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9-10 lbs of vacuum is not much. A stock motor should have around 17. If the engine isn't worn out and there are no vac leaks, I'd go ahead and replace the cam like you were thinking.
That is just me though. I don't like big cams for the most part.
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03-05-2014, 10:15 AM
(This post was last modified: 03-05-2014, 10:42 AM by snipes243.)
Is your idle A/F still searching (mean is it still moving around). Normally if your ADL cell is over 25% you need to give it more fuel. Is there any way you could post a pic of your ADL (correction table) and your A/F table?
68 Half cab
