Troubleshoot surging at idle

**sturgillbd** · 05-24-2018

Your datalogged spark doesn't match what is in the bin file. I have been trying to find what is causing the commanded spark advance to be lower than what is in the tables. Most places I checked it was off by approximately 5 degrees . I also notice your egr is commanded on the whole time the vehicle is running. I will dig further as I get time.

**only_1** · 05-24-2018

There is no egr on the truck. It is plugged off.

**only_1** · 05-24-2018

Would a vacuum leak cause these problems?
If the EGR is always on, in the program, it would mean that the EGR spark correction would always be on right? So that would be the 4 degree drop in timing?
-I zeroed this out for the next run to verify this, in addition made changes to try to disable EGR in general.

**sturgillbd** · 05-26-2018

Don't think you have a vacuum leak. Something is commanding the egr on and it seems like you have it disabled by scalars. I did a bin compare between your bin and BJYL and found several differences outside the defined parameters. You may need to start with a fresh copy using your timing tables etc .

When replaying your datalogs, do you see the EGR being on all the time?

Brian

**only_1** · 05-26-2018

I noticed the differences too. I didn't know what caused them. I assumed it was the guy who attempted my tune before. I will poke around the forum for a clean version to start with and input my changes.

**only_1** · 05-27-2018

As recommended I created a new bin file from one I found on here. I put in the tables for fuel, timing, egr, etc. I still have the idle hunting problem. The problem is muted when the truck is at idle in gear, but very evident in P/N. I attached the bin file I modified and the log file. Hot idle happens at the end of the file.

I am getting tired of fighting this thing. Do I just put in a Vac Ref Fuel Pressure Regulator and put the smaller injectors in?
To me that would add complexity, but I am not sure what else to do at this point.

I have looked but have not found an explanation of all the parameter use equations. Can anyone point me to these so that I can see how each is used to calculate what the computer is commanding?

Thanks!

**only_1** · 05-27-2018

Why does my fuel pump voltage change when sitting at idle?

Does ECM change voltage or does it just monitor it?

I will be very happy and yet frustrated if my problem is something like a weak fuel pump relay.

**sturgillbd** · 05-27-2018

I'll view your bin and datalog this evening. I got called out to work yesterday eve and didn't get home until about 7:00 am this morning. I will make some adjustments to your bin and you can try them to see if it calms the idle surge

**only_1** · 05-27-2018

I tried a few things with no real change. I think I am at the point of bumping idle speed up to 800 or running open loop idle. Either would be fine.

**only_1** · 05-31-2018

Now that we have made some progress on the idle and running, I have another question. It seems like when coming to a stop, or slowing down in general, the truck is holding on to the gear. Which parameter am I missing that would release it from engine breaking quicker?

**sturgillbd** · 06-01-2018

There are decel fuel cutoff parameters and also tcc lock/unlock parameters. Does it feel like the torque converter isn't unlocking or engine braking? I have a manual trans so I cant be of much help on Auto parameters. There are several on here who have done tuning on the trans parameters if that is what you are needing help with.

**woody80z28** · 06-04-2018

http://www.gearhead-efi.com/Fuel-Inj...unerPro!/page3

There's info there how I set up my AEM wideband. I also had trouble with the 0-5v for a bit.

Fighting my own surging idle on my v6 of similar cam duration too...