Hi everyone, this is my first post here at thirdgen.org. I just wapped out my 305TBI for a carbed 355 from a Corvette, and now it won't stay running. It has a vacuum advance distributor, a red MSD ignition box that hooks up to it, edelbrock carb with electric choke, edelbrock manifold and a mallory fuel pressure regulator. It starts and runs fine in fast (cold) idle but when it goes to kick down to regular idle it dies. I've adjusted the idle, air/fuel mixture, choke, timing, fuel pressure etc.. and it still dies no matter what. It's getting enough fuel and it's at the right pressure, the timing is set correctly, the plug wires are in the right order etc etc etc... It seems like the spark just cuts off when it kicks down because the fuel pump shuts off after it dies. I've been having this problem for the past week and it's the only thing stopping me from driving my car!! Any help is greatly appreciated!!!! Sorry for the long post!

Thanks,
Steve

 

That doesn't sound right. Make sure your fuel pump is getting 12v all the time.

 

Fuel pump is getting constant 12V, it seems like the spark quits though...

 

I forgot to mention this started happening out of nowhere one day. Also if I give it any gas it will die, someone said a bad coil. Maybe fuel delivery?? Has a new fuel filter. I need help ASAP I can't even drive my car out of the garage without it dying!!!

 

Timing is set right? My blazer would do the same thing with a 454, but I had the timing advanced wayyy too farrr

 

The book said 12 degrees before TDC so that's where it's at..

 

Does it idle fine? Maybe you have burned some spark plug wires?

Make sure fuel filter is CLEAN, I have had a brand new fuel filter and ran my blazer on empty for 10 miles looking for a gas station....I ran on fumes and it clogged it all to hell.

 

It idles great until it kicks down and then it sputters and dies no matter what. Spark plug wires are fine...

 

Could my box have overheated? It sat on my valve cover when I drove it, maybe the heat messed it up?

 

???

 

Vacuum leaks will cause this.....high idle can keep it running until you let off the gas and then it can't campensate like an ECM would for the increased amount of air compared to the amount of fuel....