AE at idle, 16197427 ecm

[Davis_1377]

AE going active at idle, ive tried changing map difference and several other things with no luck. Running a big cam and map readings are pretty well consitant, cant figure out what else to try.

[Davis_1377]

No one?

[sturgillbd]

I just viewed your log. AE came in a few times at idle but wasn't that bad. You can try adding some timing to the idle spark table at the 400-800 rpm cells up to about 60 KPA. You are at 14 degrees now and with big cams, raising the idle timing can help make more vacuum and the engine will idle smoother. Some tuners use up to 25+ degrees of idle timing. Big cams with lots of overlap cause reversion which in turn causes an unstable map signal. I saw where you had moved the map difference for ae at idle up to 25.5 kpa. If you add timing, you may lose some of the choppy idle.

Hope this helps,
Brian

[Davis_1377]

Sometimes it does it more often like when its in gear. I moved the map difference for ae at idle hoping to fix the problem but doesn't seem to affect it. I was hoping to keep the choppy idle as its not very choppy as it is, ill add timing and see what happens.

[Fast355]

Sometimes it does it more often like when its in gear. I moved the map difference for ae at idle hoping to fix the problem but doesn't seem to affect it. I was hoping to keep the choppy idle as its not very choppy as it is, ill add timing and see what happens.

Is the IAC moving when you see the AE event?

[Davis_1377]

Is the IAC moving when you see the AE event?

Yes, when AE goes active i can see 2 to 5 IAC steps added, i have to playback slow and watch the monitors page and i can see the IAC spike everytime AE is active.

[Fast355]

Yes, when AE goes active i can see 2 to 5 IAC steps added, i have to playback slow and watch the monitors page and i can see the IAC spike everytime AE is active.

Its the other way around! The IAC is causing the AE. There is a parameter for AE Pulsewidth vs IAC count that adds fuel for the air entering the IAC.

[Davis_1377]

Its the other way around! The IAC is causing the AE. There is a parameter for AE Pulsewidth vs IAC count that adds fuel for the air entering the IAC.

Is AE vs. %IAC Flow Difference the same, this is all I see?

[Fast355]

Is AE vs. %IAC Flow Difference the same, this is all I see?

Yes, I forget that the 7427 used % IAC flow. All the older TBI stuff was Steps. If its going rich when the IAC opens reduce the value and vice versa for lean.

[Davis_1377]

Yes, I forget that the 7427 used % IAC flow. All the older TBI stuff was Steps. If its going rich when the IAC opens reduce the value and vice versa for lean.

It dont seem like its making much difference in rich/lean but with iac opening and injector DC constant i guess it would make it more lean. I moved %IAC Flow and AE still goes active and I can't feel a difference no matter where i move it. Anyway to make IAC more steady?

[Davis_1377]

I set Lower IAC Limit and Upper IAC Limit both to 0 and it fixed the AE going active at idle and AE still works as normal. Can someone explain what these 2 settings actually do?