Truck falls flat after 3000 rpm.

**joegreen** · 01-26-2017

Hello, I have a 78 350 swapped to tbi. I have been tuning the ve table for a few days. It has a th400. If i put it into second gear and floor it once it hits 3000 rpm it feels like i am driving into a massive head wind. It wont really go past 3000 rpm when floored. My camshaft is pretty worn and was wondering if that could cause that issue. Below is a picture of my average blm's on a 20 mile drive and my ve table graph. Looking at stock ve graphs it looks like the graph ramps up from idle to 3200 rpm where as my graph makes a big dip around 2000 rpm. Is that an issue. I have been making the ve adjustments using daves excel spreadsheet. So i guess my question is is does the ve graph look like it has a problem or could it be shaped like that because of my worn camshaft or does the ve graph look fine as long as the blm"s are ok?

**joegreen** · 01-26-2017

Also i tried all types of searching but i cannot find out how to turn off open loop idle so it idles in closed loop. The open loop idle is throwing off my blm measurements when idling in traffic.

**Fast355** · 01-26-2017

I am going to guess it is likely timing related. The old heads need a good 8-10° more timing across the board than the TBI heads. Once you fix the lack of timing I am sure your VE fuel tables will look massively different. Dpes the truck still have the old pellet box cat on it?

**joegreen** · 01-27-2017

What is a pellet box cat? catalytic converter? Ok so ill start messing with timing? I tried looking through all the parameters but could not find a way to tun off open loop idle.

**Fast355** · 01-27-2017

Originally Posted by joegreen

What is a pellet box cat? catalytic converter? Ok so ill start messing with timing? I tried looking through all the parameters but could not find a way to tun off open loop idle.

Would probably be easier to just swap to a different .bin that had closed loop idle. Fixing your .bin requires altering numerous constants.The pellet box catalytic converter is a horribly restrictive catalytic converter, cat for short that GM started using in the mid to late 70s. .