cold start misfiring/sputter

[Ichiro718]

hello all. im doing my own tune on my car, and so far, I have idle sitting pretty good. fan comes on and drops temp and does everything its supposed to do. now as far as my issue, when I first start the car up, im getting sputtering, and what sounds like a misfire going on. once I give it a touch of gas and its started warming up, then its ok. id like someone to take a look at my calibration and datalog and tell me if they see something that's wrong or concern or what have you. im not looking for an answer, im looking for a slight push so I can figure it out. a clue, if you will..

b18c block
ls crank
Nippon racing b16 81.5 pistons
skunk2 valvetrain
b16 cams
skunk2/type r intake manifold
64mm tb
t3t4 turbo kit
fic650cc injectors

[TTR]

I'm going to assume you do not have your wideband on a relay. There is no A/F reading for the first 40 seconds. If the issue happens within the first 40 seconds you won't be able to see it as the sensor is still warming up. I'd also zero out the cranking fuel trim that's at 15% and see if that has any effect on it. I've never had to change that from zero.

[Ichiro718]

Oh i didn't know i was supposed to hook up the wideband to a relay. What would that do? I have a relay that i can install.
Do you think because the sensor is warming up, that can give me false afr readings?

Why would cranking fuel affect cold start?i should e stated i don't have any problems starting. Starts up fine.

Do you see in the graph section where everything just dropped? It does it twice or 3 times i think. What do you think that is?

[TTR]

You don't have to use a relay it just ensures that the voltage under cranking stays high enough to keep the wideband on. It will give you the wrong reading until the sensor heats up. Judging from the fact that almost every sensor spikes at the same time it may be the ecu or ground or power to the ecu.

[Ichiro718]

so If I install a relay, the gauge wont shut off when cranking? or you are specifically talking about the o2 sensor warming up?

-so you see how the afr goes from 1.36 then it drops to .79, is that the o2 sensor warming up?
-if I was having a voltage issue, why does it only happen at first? it doesn't seem to happen once the car is warmed up but ill go over and check. im running a battery relocation kit as well

im going to take a video on start up so you can hear how it sounds and you can help me compare it to the graph. If im picking up what you are putting down, I need the relay so the sensor can warm up faster and then ill be able to accurately adjust fuel map for cold starts?

[Ichiro718]

I mean, I haven't even set the idle just yet. im kind of confused on the directions. it says:

get car to temp
unplug sensor
adjust cable so idle is at 450
plug in sensor
adjust slider

I have a professional products 64mm tb and its adjusted to where its not barely open. i cant close it anymore. i have between -18 to -21 on the vacuum guage so im fairly certain i don't have a leak. how should i go about it? unplug, then screw in the screw until idle goes up, then bring it back down, then plug it in, THEN adjust the slider? when i give it gas, idle comes down then slowly increases back but i think that might be due to the compensation of fuel and things of that nature.

what are your thoughts?

[Ichiro718]

i also have knock disabled. i have a new one to put on but its such a tight fit, i just disabled it. id actually like to turn it back on and make it functioning but i hear that when you go turbo, thers too much vibrations and the knock will try to pull timing for everything. its not accurate so people go to the GM one i believe. jeff evans talked about it in one of his videos. i also haven't touched timing yet as i don't have a dyno and im doing all street tuning, but timin is from one of the basemaps that was on hondata when i started so hopefully its ok

[TTR]

Correct if you use a relay it will read while cranking. If you turn the ignition on and wait for the sensor to warm up and once you get a reading in the software you will be able to see what its doing under cranking and immediately after. The spikes in the trace look like a loose ground or corroded wires on the thermostat ground or maybe the ecu, hard to say. As far as getting the idle set, get it started and up to temp. Go to online, set timing and set the timing. Make sure the A/F is where you want it. Set both target idle tables moving and stationary the same and make sure the minimum idle speed is the same as whatever value is set to in the other 2 tables at 177 and up. Back the air bleed on the throttle body out one turn before you start and once warm and everything else is set move the slider to hit your target rpm. You don't need to unplug the iac. 95% of the ecu's don't have a knock board so I don't use the factory knock sensor anyways. If your concerned about knock there are other alternatives that are better.

[Ichiro718]

Oh! Ok so at least for right now, i can turn the key to the on position and wait about a minute before starting up. I'll be able to see the datalogging and the suggested percentage change for the lamda overlay and I'll be able to adjust that whole section accurately, correct?

I did set the timing already, i should've said timing table. But I'm set at 16 degrees.

It eventually will idle down to about 950-1000 and that seems to be where it wants to settle at, but that's after a while. It could be because it's cold now and the pops and missing could be from the fudged fuel map because i wasn't aware of the o2 needing warmed up...😅i have to fix my leaky brake line so then i can try to drive the car. Can I pick your brain about closed loop tuning?

[Ichiro718]

"Set both target idle tables moving and stationary the same and make sure the minimum idle speed is the same as whatever value is set to in the other 2 tables at 177 and up"

What do you mean at 177 and up? What's 177 supposed to be?

[Ichiro718]

Nevermind on the last post

[Ichiro718]

So i left the key in the on position until the afr started giving me a reading. I seen this and i increased the fuel percentage in the coolant temp/fuel pressure section and i increased fuel by 3% on the map and now she starts up much cleaner. I can pull just a bit of fuel in some sections( reading like 1.03-1.05) but it's much better. Much cleaner. Here's a video of how it sounds.

https://youtube.com/shorts/ii7GlKT_k7Q?feature=share