ZR-1 Net Registry Forums - View Single Post

XfireZ51 · 01-10-2008

Shawn,

I did a search on ThirdGen regarding surging decel. This was in a thread that deals with another ECM, the EBL. I won't go into what ot is but I used it for almost 2 years. Outstanding piece of work by RBob. That ECM in combination with Moates OStrich and Tunerpro RT really changed tuning.

So here's RBob's advice:

"'Option word 3 - bit 5 - OpDcl' is probably set. This will put the ECM in open loop fueling during decel. Once un-set, you may experience surging during decel. If so it may be either the proportional gain at the gms/sec airflow is too high. Or the ECM is switching in and out of async fuel mode.

DFCO, to enter this the vehicle speed needs to be above the MPH parameters, and the RPM above the RPM parameters. This is usually for highway speeds on a thottle lift. Keeps the CAT(s) from melting.

RBob."

Here's the link to that thread.
http://www.thirdgen.org/techboard/di...=surging+decel

Granted EBL code is not the same as our LT-5 stuff but I think you'll find that the controls do pretty much the same thing. Its just that RBob has provided an .xdf which makes all those paramters available to the tuner along with a bunch of tuning aids.
I agree with Todd that first and foremost you make sure everything is "mechanically" correct before turning to the tune.
As a side note, if any of you don't know RBob, he is one of the more highly knowledgeable sources over at 3rd Gen. Heck of a nice guy too. I keep begging him to build a version of EBL for our LT5s.

01-10-2008	#8
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,686	Re: LT5 ECM Tuning thread Shawn, I did a search on ThirdGen regarding surging decel. This was in a thread that deals with another ECM, the EBL. I won't go into what ot is but I used it for almost 2 years. Outstanding piece of work by RBob. That ECM in combination with Moates OStrich and Tunerpro RT really changed tuning. So here's RBob's advice: "'Option word 3 - bit 5 - OpDcl' is probably set. This will put the ECM in open loop fueling during decel. Once un-set, you may experience surging during decel. If so it may be either the proportional gain at the gms/sec airflow is too high. Or the ECM is switching in and out of async fuel mode. DFCO, to enter this the vehicle speed needs to be above the MPH parameters, and the RPM above the RPM parameters. This is usually for highway speeds on a thottle lift. Keeps the CAT(s) from melting. RBob." Here's the link to that thread. http://www.thirdgen.org/techboard/di...=surging+decel Granted EBL code is not the same as our LT-5 stuff but I think you'll find that the controls do pretty much the same thing. Its just that RBob has provided an .xdf which makes all those paramters available to the tuner along with a bunch of tuning aids. I agree with Todd that first and foremost you make sure everything is "mechanically" correct before turning to the tune. As a side note, if any of you don't know RBob, he is one of the more highly knowledgeable sources over at 3rd Gen. Heck of a nice guy too. I keep begging him to build a version of EBL for our LT5s.