Tries to die when I blip the throttle in park

[ws6ick]

When I blip the throttle at idle, it tries to die but it doesn't. The idle drops to around 500 rpms for a few seconds then comes back to idle which I set at 850 rpms. It only does it in park. Any ideas? Should I up the idle rpms a little? Right now I have it set to 850 rpms in gear and park. I have a 228 cam, LS6 intake and ported 243 heads. What table should I adjust to fix this and which was should I go with it? I was thinking the throttle cracker table would solve this. Here is a snapshot of mine. Take in mind that a professional tuner had adjusted the table because it would pull even when I let off the throttle in gear, like the cruise control was on.

[Cantalope Kid]

Have you run the idle air config. to make adjustments to your in gear/park?

[ws6ick]

Have you run the idle air config. to make adjustments to your in gear/park?

OK. I did some research and found out what your talking about. I will try the Idle Air Config to get my base running airflow correct.

[jimmyblue]

If the base airflow is short, for desired idle RPM,
you may undershoot. But undershoot to the
point of crash, is probably another problem -
loop instability. Which in my experience comes
from low-RPM mixture error as much as anything
else. You need to make the motor more "agile"
so it can climb back out of any hole. More
advance (but not so much, that adaptive spark
has no upside ability) and leaner fueling (bear in
mind that with cam overlap, indicated AFR will
be leaner than real chemistry) perk up the idle.

The tough thing is to get any good data for the
400RPM column of the VE table. You never get
to be there steady-state, but you swing into it
on idle undershoot events.

[ws6ick]

Have you run the idle air config. to make adjustments to your in gear/park?

Ran the idle air config and input the average into base running airflow. Seems to idle well when started but it wants to hunt idle on warm startups. Almost wants to shut off but after 3-4 seconds, it idles fine. I haven't checked how the cold starts are.

[blownbluez06]

I'm not great with the idle stuff, but if you're having trouble for the first few seconds after starting, try playing with your startup and friction airflow tables. (raising them). Last car I worked on did the same thing and that was the fix. I also played with the timing to achieve about 8 kpa more vacuum and raised the idle and main spark tables by the amount it took to achieve that vacuum in the idle area.

[Cantalope Kid]

I also played with the timing to achieve about 8 kpa more vacuum and raised the idle and main spark tables by the amount it took to achieve that vacuum in the idle area.

I agree with adding more timing to obtain more vacuum at idle.

Can you post up a copy of your tune? I suspect this may not have been done by your previous tuner.

[ws6ick]

Here's my tune. I drove the car around today to put some miles on it. It seems to be getting better but you guys can look at my tune and see what's wrong.

[ws6ick]

With the tune I posted above, car runs great and warm starts are fine and it does not try to die when I blip the throttle. I started the car this morning to test the cold start. Now the cold start is off. It hunts idle for 8-10 seconds and then idles just fine. Should I try to add a gram or two to my cold temps (80 degrees and below) in my base running air flow tables?

[blownbluez06]

Probably in there or OLFA tables. Log it from a cold start to find out.

[Cantalope Kid]

No, just run the idle air config. from a cold start now. Adjust accordingly. Bythe way just the small steps you have done so far using the idle air config. HUGE! Remember in the future to pass along the information you have learned. Several known professional tuner shops STILL don't know how to tune idle in correctly.

[ws6ick]

No, just run the idle air config. from a cold start now. Adjust accordingly. Bythe way just the small steps you have done so far using the idle air config. HUGE! Remember in the future to pass along the information you have learned. Several known professional tuner shops STILL don't know how to tune idle in correctly.

I did run the idle air config from a cold start and I input the numbers in the tables. It still wants to hunt idle when the engine temp is 80 or below. Will the pcm learn the new numbers over time?

[cbeutelschies]

Man, I'm having the same issues you are now.

I had surging idle problems when warm and it would dip and dive, trying to find the idle. I've since resolved the warm idle problem and the dips after revving, but my cold start is off now. As soon as I start it cold, it revs to 1500 for a second and then drops all the way down to like 400, overshoots, and then dies. If I pedal it at all and keep it above 1000, in like 5 seconds or so it will level out and have a smooth idle. So, I'm all ears for what the fix for this is.

Let me know if you had any luck fixing this issue. I'll keep searching for now...

Thanks,

Cody B.

[ws6ick]

Man, I'm having the same issues you are now.

I had surging idle problems when warm and it would dip and dive, trying to find the idle. I've since resolved the warm idle problem and the dips after revving, but my cold start is off now. As soon as I start it cold, it revs to 1500 for a second and then drops all the way down to like 400, overshoots, and then dies. If I pedal it at all and keep it above 1000, in like 5 seconds or so it will level out and have a smooth idle. So, I'm all ears for what the fix for this is.

Let me know if you had any luck fixing this issue. I'll keep searching for now...

Thanks,

Cody B.

I added 3 grams across the whole startup Initial and startup friction airflow tables. That fixed my cold and warm starts.

[cbeutelschies]

Well...I tried adding 3 grams across those two tables and it helped...but still surges for about 3 or 4 seconds afterwards.

I'll keep digging and searching, trying to figure out what else to adjust.

Thanks,

Cody B.