[ImpalaGuy]

Thanks for asking and sorry I've been so quiet. I've been crazy busy at work plus the truck has been frustrating so I haven't had much good news to report.

First here's my story on what comfounded me for the last several weeks: the dang thing would almost never start when cold. Here in Kentucky it was near 0 every morning and didn't get above freezing during the day so this got old REAL fast. Brian at TBIChips and I went through lots of programs trying to richen or lean it or change the timing and nothing had much effect. Checked fuel pressure, timing, injectors, nothing seemed wrong. Hot or warm starts were fine, and once it started it ran pretty good. Well to make a long story short it was the STUPID COIL. I used the same one as I had on the old motor so I never really suspected it, especially since it ran fine once it started. My clue was when I decided to check the timing while cranking the engine. I noticed that the timing light missed a flash sometimes. At the time I didn't think much of it and moved the inductive pickup closer to the distributor. Of course the timing was fine. It wasn't until later I started thinking about the intermittent flash and wondering why I had to move it.

I've always got to keep reminding myself not to ignore data. Too many times it's those little things that you brush aside that end up being the biggest clue to what's wrong.

In this case I think the coil just didn't have quite enough "oomph" when the battery was cold and the cold engine sucked more current to turn over. Once it started and the alternator took over the coil sparked fine. A warm battery/engine and it must have had just enough to spark. I think that the new distributor I put in there may have something to do with it as well. It may take more spark to jump from the pickup. At least that would explain why that old coil never gave me a problem on the old motor. Who knows. Anyway a new MSD Blaster coil fixed that problem real fast.



So that's old news, now for the new news...


Right now the truck runs fine in general driving or WOT but still has two issues:
Hesitation. Pretty bad when I smash over 50% throttle from idle. Sometimes it dies. I've combed the intake and TBI for vacuum leaks and haven't found anything wrong mechanically.
Poor running in open loop. It spits and misses and pops. Once it hits closed loop (3-4 minutes) it clears up almost instantly.

I think both of these are the tune, but I can't complain about Brian at TBI Chips since he's been very responsive. In fact he's sent me SEVENTEEN TUNES so far trying to work these things out. Sometimes even two a day. And the first 6 or 8 was chasing the stupid coil problem above and the fact that the xtreme-fi adjustable fuel pressure regulator won't go below 17psi.

The good news is that I put in a new fuel pump (Walpro 190l/hr) and at WOT it runs GREAT. Yank's Truck Thruster 2600 stall converator stalls around 3000 behind the 383, so the engine really jumps into its power band. I'm anxious to get it to the strip this spring.

So that's the scoop. I'll keep in touch.