Cold Starting Problems

[Gregory]

I have a 2007 Avalanche 5.3 4x4 with a little camshaft and cold starting problems. It happens with both 87 octane and E85. I use E85 almost exclusively.

I suspect it is too lean initially. Any suggestions? If so, where do I make the changes?

A dyno, tune and log are attached.

Note: Here is the key to the dyno chart lines.
Stock Pull - Blue Line
After Camshaft - Black Line
After Camshaft & Tune - Red Line
The missing segments in the lines is due to the extra thick plug wire insulation.

The camshaft is: 208/216 .554”/.561” 114LSA +4
Attachment 21724

Attachment 21725

[Gregory]

Well, I went to the "Cranking Fuel" table under Fuel Control > General and added 10% more fuel across the table from 68*F and cooler and then applied smoothing to the table.

Since most of my problem is when the engine is cold no matter what the temperature of the outside air is, I figure this is a good place to start.
However, I should note that the colder it is outside, the worse the starting is. Sometimes the starter will time-out when starting in cool weather (below 50*F).

I'm at a loss as to why the cranking seconds goes to 43200 seconds/12 minutes. Could it be an elapsed time since the last start or drive?

But, if anyone has some good ideas, I do welcome them.

It is also worth noting that the engine will stutter or cough when driving down the road without warming it up.

[99LS1SS]

I'm having the same problem. Does anyone have any input?

[maxgee]

Had the same issue in GA this past winter for a visit. It was 40 degrees and it took me a while to get it started.
Trying to figure out a solution...I did add in 30 percent more fuel and it help greatly.

[Google]

make a log with ve airflow, dynamic airflow added to your log. start logging then crank untill it starts then post your log. Wide Bamd would be nice too..

[IDRIVEAG8GT]

My suggestion would be to raise the Minimum Idle Airflow and Startup Airflow tables by .2 Lb increments until you get it better. Have to do that for each and every cam upgrade.

[Google]

Here is some good info on E85 including AFR, starting problems and much more. http://en.wikipedia.org/wiki/E85_in_...tio_comparison