Engine surges on cold idle
Engine surges on cold idle Hey guys, looking for some help. I just put my 402ci LS2 in and when I started it for the first time it fired right up, seemed to try and idle for 2 seconds and then the rpms started to race up to about 3500-4000rpm before I killed it.
I am pretty sure, like 99%, that there isn't a vacuum leak on the intake. If there was I would think it would have to be huge to cause that to happen? of course the laptop died before I started it so I couldn't get a log, but I wanted to see if anyone could look at my tune file and see if there's anything you noticed that could cause this to happen?
If there is a vacuum leak, what am I looking for on the logs?
I am pretty sure, like 99%, that there isn't a vacuum leak on the intake. If there was I would think it would have to be huge to cause that to happen? of course the laptop died before I started it so I couldn't get a log, but I wanted to see if anyone could look at my tune file and see if there's anything you noticed that could cause this to happen?
If there is a vacuum leak, what am I looking for on the logs?
Last edited by 84ta406; Oct 4, 2024 at 06:31 PM.
Launching!
Joined: Jul 2014
Posts: 295
Likes: 102
From: Duluth, Minnesota
Hey guys, looking for some help. I just put my 402ci LS2 in and when I started it for the first time it fired right up, seemed to try and idle for 2 seconds and then the rpms started to race up to about 3500-4000rpm before I killed it.
I am pretty sure, like 99%, that there isn't a vacuum leak on the intake. If there was I would think it would have to be huge to cause that to happen? of course the laptop died before I started it so I couldn't get a log, but I wanted to see if anyone could look at my tune file and see if there's anything you noticed that could cause this to happen?
If there is a vacuum leak, what am I looking for on the logs?
I am pretty sure, like 99%, that there isn't a vacuum leak on the intake. If there was I would think it would have to be huge to cause that to happen? of course the laptop died before I started it so I couldn't get a log, but I wanted to see if anyone could look at my tune file and see if there's anything you noticed that could cause this to happen?
If there is a vacuum leak, what am I looking for on the logs?
Took everything apart today and while doing so I found two issues. One, the Dyno shop drilled a 1/8" hole in one of the EVAP ports on the LSXrt manifold. The other thing I noticed is.. the brake booster port on the side of the intake manifold. Completely forgot to put a plug on it, my kit only goes to 3/8 and I forgot to grab one from work.. oops. Starts up like a champ now, idle definitely needs some work as it started to surge when it came down under 1000rpm. I'll post the log tonight if someone can look at it and point me in the right direction to clean it up. Still waiting on a AC bracket to come in and then I can button up the rest of everything.
I was wondering if anyone can look at my log and point me in the right direction on what to change? Once the idle tried to drop below 1000rpm it started surging pretty bad and I'd like to try and clean that up a bit before trying to drive it.
Here is the log and the tune file is up at the top.
Here is the log and the tune file is up at the top.
