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Discussion Starter #1
well I have been fiddling with my engine and I am having some problems with it and I am not sure why... at idle on occasion and not consistantly it sounds like someone is hitting my header with a wrench or rock and it is reverberating all the way through the exhaust piping. I think it has something to do with the timing but I am not really 100% sure.

But the main problem is after the engine sits for a little while and warms up, I put it in gear and move it, then it won't idle by itself I have to give it some gas for it to stay alive.... and if I move it back to the same location it was before trying to move it, it idles perfectly fine. I have replaced the Idle Air Control Valve and have not clue what this is... does anyone know what it could be?
 

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is the car on flat ground when you move the car also is the car an auto or a stick then you also should see if your firing order is correct and make sure your wires are in good shape you might be getting a cross fire
 

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Discussion Starter #3
its not on 100% flat ground but it has a fairly full tank of gas... its a stick... and the firing order is right I checked it already and the spark plug wires worked seemingly perfect on my stock engine they are Taylor 9mm wires.
 

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Discussion Starter #5
I forgot to mention that this engine has FRPP B cam and GT-40 (iron) heads on a 302 bored .30 over stock stroke with 6.8cc domed pistons.

I think I may just need to play with the idle screw... what does a B cam normally idle at? because right now when its cold it sits around 800-1000 rpm until it starts to die unless I give it gas... then before it dies it will rock from 1200 to like 200 rpm before killing itself.
 

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ahh.. the good ole surge and die.. check the sticky about setting the base idle and give that a shot.

Also agree with the timing. I'm not sure what the sound is, but it could be an exhaust valve opening too early.. are the headers glowing red at all? (check this when its dark out if you cant tell when its light)
 

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sounding like hitting your exhaust with a wrench... deff has to do with timing... sounds like it might be detonating...
 

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retorque your header bolts then check timing
 

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Discussion Starter #9
the headers do not glow red as of now... but I have retorqued the bolts. I dont think it is detonation because it doesnt really sound like a bad combustion (Ive heard that before)... but it does send a nice puff of air out the drivers side tail pipe when it does it.

I have worked with the idle a little with no luck but I am going to continue to work with it.
 

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try pulling the dist. and re-stabbing it 180' I had a stang I built do that and I fought it for days. Double check that you are on top dead center on the compression stroke then re-stab. even if you are sure I'd try it again.
 

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Discussion Starter #11
oh I am 100% sure of that because the first time I started the motor it was straight flames out the tailpipes because it was firing on the valve over lap... I fixed that.

but I am thinking of taking it to a dyno shop and have them set the timing and mess with the idle just so I know everything is perfect and while I am there they can tune the ECU and I will know exactly how much I put down.
 

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Discussion Starter #12
I followed the tinstruction for setting idle... and it does so perfectly before I try to move it... but now even when I move it just 50' or so it wants to die on me.... could this be because of a bad Throttle Positioning Sensor? what else could it be?
 

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IAC most likely
 
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