My coworker is letting me borrow his obd1 scan tool so I can read some live data from the computer. I believe I'm running lean until the o2 kicks in and then the car seems to run decent albeit harder on gas than I remember. The scanner is telling me that, with my key off, the iac is reading 160. I had it idling and it was between 70-40ish iirc. What is a normal reading supposed to be?

 

Engine warm iac should be 20-25 steps. Cold engine it’s at 160. How can you tell that it’s lean when cold without a wb ?

 

I suppose I don't know for certain but it seams to be logical. I just put a ported set of 081 heads on my lo3. The car runs roughish at idle and will backfire when accelerating while cold. Once it warms up it runs fine. Just harder on gas. Which could be from colder temps and the better flow of the heads. I've been chasing issues with the engine since I got it back together. Just going step by step until I have it running as good as I can. I could be there and it's just the factory tune not liking the mods. I know little to nothing about tunes I will admit

 

The popping could be a lean miss. Working with cold start enrichment or a wideband gauge would be a way to see what’s going on. Tunerpro rt is a much easier way to average fuel trim readings to adjust volumetric efficiency if closed loop needs work. Without narrow band movement in open loop it’s really a challenge to correct for a lean condition unless you just experiment with cold start enrichment.

 

Just curious what’s base timing at ? Does the engine like more advanced timing since the head swap ?

 

I know base timing on a tbi 305 is 0 and that's where the engine seemed to be the happiest. I might experiment with advancing a couple degrees or so

 

Right now with the engine at 140° the iac is at 48 and idle is fluctuating slightly. Around 100 rpm difference

 

Looking back at the binary it seems it’s slightly different than tpi that I’m more use to. Iac steps to target rpm will be 160 max rpm
1400 and start to drop at 98.6 f . At 147f it stabilizes to 65-86 steps and on say an automatic targets idle at 525 rpm.

 

Okay I think I understand that. I'm just trying to trouble shoot some and I'm finding that there's much I know nothing about. I really appreciate you taking the time to help out

 

Okay so I have a new development. Integrator is at 130 and block learn is at 118. My TCS also reads about .62 at idle

 

Tcs = tps ? Are you having issues at idle ?

 

Yes, sorry. Tps. I found the new injectors I put in were dribbling and basically just pouring fuel. So I put my original ones back in and they spray much better. Right now when I start the car it's sounds like it has a massive cam. I'm going to inspect my plugs, wires, cap, and rotor. Just noticed the tps reading and read on some of these threads that .40 is roughly where I should be. It has a pretty clean sweep from .60-4.40 so it might help to adjust it

 

Update: I resolved part of my issue. I had replaced my fuel pressure regulator a couple weeks ago and didn't pay much mind to the length of the spring. The new one was about 2 coils shorter. Put the old spring back in and put in the new injectors and the car runs much better now. Still need to pull and inspect the plugs.