My TBI is finally working great. Just in case there's anyone else out there that purchased Howell TBI kit and having issue getting it to run right, there may be an answer.
I got my Howell kit about 2 years ago. What sold me was the key word phrase "turn key". I was able to get it installed got my engine fire right up but rough and rich with my original intake. Found out my 4v intake was not compatible so installed Edelbrock performer intake without EGR. Performed minimum idle adjustment and got it to run better. That was about 2 years ago. I had hesitation when engine was cold but when warmed up, it ran okay. I originally had it hooked up to manifold vacuum which gave me issues when engine was warmed up. Then I tried ported vacuum which was fine warmed up but gave me more rough cold start. Then I tried CTO and manifold when under 160 then to ported. I just couldn't get rid of cold engine hesitation. One benefit of TBI was remote auto start. For the most part during winter, I just let it warm up and then go. Still better than carb. Even in the summer time, I have to feather the gas pedal when engine is cold to minimize hesitation.
I worked on it off and on for a while to see if I can get it better. I couldn't get much help from Howell. I really wanted to get it run better before this winter. This was accomplished by getting help from HamiltonEFI. He sent me a tuned chip for fuel only setup that took care of my issue. I can now turn on the engine and put it in gear and drive out without hesitation right away without waiting for warm up. No more feathering gas pedal until engine warm up. It is well worth spending $160.00 for custom tune to fix $1500.00 mistake.