Thread: Rich on hot day

Most of the tuning I've done of late has been on cooler days or evenings, but today it's pretty warm, and the car is in the mid to low 13s at light load and cruise. Don't have laptop with me, so hoping internal logs will download when I get home, but what tables should I be looking at to correct this?

Since you are running speed density, you will want to take a peak at the IAT fuel trim tables.

Shoot me over the logs and I can lend a hand.

Internal logs are still odd data, despite clearing it all etc, so ive got nothing to work with until i can take it for another drive with laptop connected.

Should i be using IAT density correction tables?

On the iat fuel trim, ive got a maximum value of -6 at 110C, and -1 at 50C.

Just used a full tank of gas with current setup, 12.5 litre per 100k (18mpg), which is pretty poor, but i guess i did do some boosting doing tuning earlier in the tank.

managed to record a log ok, and the iat seemed fairly constant with what it would be on a cold night, and there is no temp compensation happening to the fueling. So it looks from the log like its just the part of the map that its hitting that was too rich, which is odd as ive spent a fair bit of time on those areas of late.

I do need to check if the sensor calibration is still correct, although i spent a fair bit of time on it when i fitted it. It seems very constant most of the time, and on warm start its like 50C, then as the air goes past if drops to around 30, and is fairly consistent from there. If it was faulty could it be that air temp is actually higher and the compensation is not allowing for this, would more intake temp normally make the mixture richer or leaner?

id def check for calibration..

i recently hooked up the other cars iat/map stuff, i was able to import my tables into his tune an i believe they read identical.. (both genuine gm sensors, both using same 4.7k resistor, both going to the adc box) the reason i say "believe" is cause his intercoolers HUGE an mine is rather small so im sure his is cooling the air more thus we didnt read identical temps when i compared

but then you could try pulling some fuel out in the IAT fuel trim table at the temps its at on the warmer days..

I think im going to check the sensor calibration to be safe.

What is "odd" about it? I have used the onboard multiple times and haven't had any issues with the data.

Maybe try to enable/disable compression and then erase the onboard storage to reset it. You can test it quickly by just simply taking a quick log with the laptop connected at idle and then download the onboard and load the log to ensure that it is working properly for you.



The IAT fuel trim is definitely the best way to handle the IAT trim, BUT it does require a bunch of setup specific tuning to get it dialed in just right.

I used your table for my car. Its very accurate and for most people, a good place to start when calibrating.

Right on!

Your using a gm iat going to the breakout box right? What ohm resistor?

Remember I could only calibrate it to as cold as I could get water so after below 30 degrees its guess work but when I compared with temps from my phone while drivig its pretty close.

Glad it could be of use to you tho

Gm IAT with the break out box. I used a 4.7k and 300ohm resistor. Even so, your table is very accurate. Weve been dipping in the below freezing a lot here lately in VA, so I have been able to add to it.