Just off idle stutter, throttle barely open (SOLVED)
Now I know I will get blasted for posting this however saying "look at you accel pump" or "your lean and going rich" doesn't really help me fix the problem. I am extremely novice at reading all the descriptions and what all the AFR numbers are and so on and so on. It may as well be in Chinese to me. With that being said, here is my issue. I have a 95 Trans Am with a 99 LS swap, stroked, ultimate LS W trans control, prc heads, Texas speed cam, kooks headers, stage 3 4l60e. Loooooong story short I hauled it 8 hours to Texas to a certified Fitech installer who got me running great. I've put about 300 miles on it and it runs good except for a few things that are more annoying than performance reducing.
At idle, at a stop sign, easing out onto the road there is a stumble, hesitation, near stall for a split second. This is "easing into the throttle" not hammering it. Ironically if I stab it I have no issue. I have adjusted the AFR 1100 to 13.5 all the way up to 15 with no change. It is currently back to 14.5. IAC steps are 0-3 at idle. I feel it is a throttle blade position issue as I also have a "hunt" at 2000rpm cruising at about 65mph and the pedal barely pressed, the rpms will cycle up and down, up and down. You cant feel it but you can def hear it and see it.
I have attempted to view my hand held on the computer but that doesn't work due to timing out and my computer never recognizing it. So I would really like to make a few adjustments because I feel like its probably something simple but I just don't know what to adjust on the accell pump even though I've read that's what I need to mess with. My Fitech installer appears too busy to assist over the phone since there is no money involved or for lack of time, but I cant go hauling it 8 hours for a simple handheld adjustment. Appreciate any constructive advise. Thanks
Ok, I saw something that got my attention to fix. You mentioned your IAC steps are 0-3 at idle. You should never have your IAC steps hit zero. You need to adjust your IAC steps up a tad.
- Get engine up to operating temp > 170
- Check your IAC steps to see what it is
- If it is ever zero, you need to turn your idle screw out I would say about 1/4 turn
- Let the engine settle and check IAC steps again
- If it never gets to zero, but still close to 0, then turn it out another 1/4 turn
- If you go too far and IAC is too high, then post again and I'll tell you how to adjust it down
This may solve your stumble off idle
Alright, I know how to do the IAC step thing. I will adjust on it. It definitely has a sweet spot between hitting zero and then next step it won’t go below 18.
I will tune on it let you know. Thanks 👍🏼
So I got it to 7 on the IAC. It took forever. I mean I was making hair moves. Just a touch open or closed on the screw would either make it settle at 21 or zero. And it idled for 3-4 minutes each time before it would creep down toward zero. I drove it and there was absolutely no change either positive or negative. Next area to work on?
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Oh well, I assume you talked with your installer about the issue? If you could save a log file, it would definitely help in diagnosing the issue. Take a log at operating temp during your hesitation and post link. Let's start with that.
Alright. I have performed the signature verification trick for my windows PC, hooked up my hand held , chose the mass storage part and my PC isn’t recognizing anything. I will do some searching on that issue and try and get some data transferred. I appreciate your time with this.
Ok so I got my PC to finally recognize the handheld. It opens several folders but log_file is not one of them.
so I loaded the pro cal and the Kline drivers. It connects however I’m not sure how to read any of my data logs or find them. I know this is so basic for the majority but it’s brand new to me and I’m terrified I’ll screw something up. Thanks
There should be a Dashboard directory under log_file directory. I'm at a loss to figure out why you don't have that. I wonder if you need to reinstall the software to your handheld.
I called FiTech today. He told me to add the
data_file folder to it on my pc then go drive it and do a log. It should save to it now.
I will know in a few minutes.
Ok so made 4 logs and plugged it up and there are now 2 Dadhboards in the
log_file
a dashboarddashboard1
a dashboarddashboard1.csvdadhboard1
neither contain anything but blank excel spreadsheets.
my log consisted of running about a mile, getting up to temp, stopping, hitting log on and starting and stopping for 30 seconds then hitting log off.
calling Fitech again