I tried adding some timing to my car today to get rid of some surge but now it wont start. Below are my curent closed tps spark adv tables. Please tell me what you think. The motor is a 383 with LE3 packageand a 24x/25x cam

0 2.0
400 31.0
800 31.0
1200 31.0
1600 36.0
2000 36.0
2400 36.0
2800 37.0
3200 39.0
3600 39.0
4000 39.0
4400 39.0

 

Thats a HUGE cam. Did you fry the computer by change while adding timing? Close TPS spark advance isnt going to help you much past 28* total advance assuming the idle is around 800-900.

 

I dont think I fried anything. Everything went smoothly while programming. It was at 29* but I bump all timing tables up 2*(closed tps,main and extended) The idle was programmed at 1000 rpms but it doesnt idle anywhere near that. It's very low like around 5-600. And I noticed my IAC counts are maxed out at 160. Haven't lookd to see if the motor was bad or not. Just started reading up on it last night. I have a BBK 58mm and I put a small piece of copper tubing in the front of the intake where the "short cicuit" IAC problem is with that TB

 

I've read somewhere that cracking open the throttle blades a little will help lower the IAC counts. This can also help if you have split BLM's at idle.

Ryan

 

Sounds like the motor is suffocating. The IAC is what controls the idle RPM and 160 is its max correction so no more air is going to get to the motor than you are seeing now which is why the idle is so low. The only way to raise it is by enlarging the IAC bypass hole(assuming the TB has one like you find on stock units) or by cracking the throttle blades a little.

 

I took off the filthy air filter thinking the same thing but no change. I will try cracking the blades open. Will the computer try to compensate?

 

The computer always compensates... that is what you are after. The objective you are after is getting more air to the motor at idle because the IAC cannot flow enough at its max capacity to keep the beast alive. Cracking the blades will accomplish this but there are better ways because idealy you wanna keep idle air in the idle air passages casted into the intake instead of letting it slip by the throttle blades.

 

i have a bin file for that cam. and the timing is 43 degrees across the board and 38 from 85 map and up. so i think your right there,, this is one of joes cams right

i have one of joe cams (well it should be here this week) going in a 355 and its a bit bigger than the le3. so i may your help when i get it in

 

Is this where the drilling mod I've heard about comes into play?

It's a Bauer Racing grind.

 

I know some people that have been know to use the drill mod on carbs to smooth idle but i think it should work the same in your case. Please, find a person with more knowledge about this before you break out the drill.

 

Most likely the problem you are having is resolved with the "drilling mod" but like I said I dont own one so I cant say for sure. Cracking the throttle blades will accomplish the same thing and you can always undo that change if you find a way to drill out the IAC bypass hole(granted there is one) on that TB.

 

Thanks Turbo. I'll check around about that drill mod for my particular TB. Bull I'll try cracking the blades first. Hopefully that will help this thing idle.