Basic tuning for mild cam? (idle, startup, etc)

[bubba68ss]

I have a 2007 5.3, 4l60e with E38 controller. I was burning through a lot of oil and lifters were very noisy on cold startup so I disabled the AFM by changing out all the hardware. While I was there I decided to put in a new cam.

It's a very mild cam, .522/.529 lift 265/271 Adv on a 114 LSA ( http://www.compcams.com/Company/CC/c...csid=1085&sb=2 )

I'm looking for a few tips on how to get the idle and startup to act like it used to. Right now the stock idle is just a little too low and it feels choppy, also sets off the misfire code sometimes. If I bump the idle to about 725 it really smooths out. It drives great and fuel trims are only 6-8% max in certain areas after logging them. Are there some basic things I can do to get this thing idling and starting right? The starting is definitely a problem after it warms up. Sometimes it just cranks and doesn't fire after warmed up.

[joecar]

522/.529 lift 265/271 Adv on a 114 LSA

What is your cam's 0.050" specs...?

You probably should being idling at 725-750 rpm.

Have you corrected MAF/VE yet...?

Make sure it is not ongesting oil thru PCV.

~Moderator~

[bubba68ss]

What is your cam's 0.050" specs...?

You probably should being idling at 725-750 rpm.

Have you corrected MAF/VE yet...?

Make sure it is not ongesting oil thru PCV.

~Moderator~

Sorry, my .050 durations are 212/218

I haven't corrected maf or ve because I don't know how, to be honest. Especially not being used to the VVE tables.

[joecar]

Do you have a wideband...?

~Moderator~

[bubba68ss]

Yes I do. I don't have a bung welded in yet. What should I do after I get it installed?

[joecar]

After you install the wb, you verify that it works properly.

Then there are there's some logging to do...

You would run VE-only (by forcing a MAF DTC) and correct the VE/VVE table.

Then you would run MAF-only (set the dynamic airflow rpm to zero) and correct the MAF table.


We're currently working on a method that corrects MAF and calculates VE from it, see this thread, we're not quite ready yet (we're still ironing out a few things): Volunteers-needed-for-E38-E67-Calc-VET-project

[bubba68ss]

Thanks I'll be watching that thread.

As far as correcting the vve table is there a tutorial for it? I was still getting familiar with the ls1b ve tables...

[joecar]

See these documents:

Links for easy reference:
E38 VVE Setup Guide
Virtual VE Tutorial

( from post #83 of this thread: E38-VVE-Setup-Guide )

[KingChalk]

I believe richening up the air fuel at idle will help the smoothness as well. And I do agree that it should idle a little higher


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[bubba68ss]

I've played around with startup airflow and idles and it seems to be running and starting pretty well. The only thing i noticed is that when I am slowing to a stop, just before I stop completely and it downshifts, I almost feel the truck pull forward under my braking. I don't recall that before. Also, when idling while rolling at very low speed I see the rpm cycling up and down about 300 rpms. Is that normal?