Idle in N whilst moving

[daveb]

I have heads/cam etc in my car, finished last week. I have the idle very good with once weird exception.

If I put the car in Neutral whilst moving it hunts all around for a steady idle rpm. Quite wildy 600-1700 rpm at times. I have logged this and what is happening is the AFR is going from rich to lean, 11-17:1.

I almost never put it in N whilst moving anyway, but I have the car idling perfect and this anomaly has me stumped.

When the car comes to a stop, the idle speed immediately locks on to the correct speed.

What mode is it in whilst it is not at rest? And why would the AFR be all over the place?

BTW DFCO is set to come on when the speed is over 90k and I have been doing this at lower speeds (40-60k) and I have not activated lean cruise yet.

Any thoughts most welcome.

DAVE

[GMPX]

Manual or Auto?

[daveb]

auto

[GMPX]

New tables in the new release to fix that problem on an Auto :)

Before you ask.....probably on Tuesday / Wednesday.

Cheers,
Ross

[bink]

New tables in the new release to fix that problem on an Auto :)

Before you ask.....probably on Tuesday / Wednesday.

Cheers,
Ross

Man, isn't it Great when new tables are coming! I get excited ........ and I don't have an auto!!

ummm... that's not true ...my Jeep is an auto.

Cheers,
joel

[joecar]

I like auto, and I like new tables for auto, and I like to modify tables to make auto trans perform tire-snapping shifts
(my favourite is WOT downshift to 1st from 35-40 MPH while next to a rice-rocket... he he he...).... :lol: :lol: :lol:

[GMPX]

Man, isn't it Great when new tables are coming! I get excited ........ and I don't have an auto!!

I know what to give Joel for Christmas!!, new tables.
In all with the new release we have over 600 parameters and tables, that's enough to keep you all busy fiddling.

Cheers,
Ross

[daveb]

Ross,

What are these tables and what do they control?

DAVE

[SinisterSS]

The new tables are fun, even on a M6. :wink:

[GMPX]

Ross,

What are these tables and what do they control?

DAVE

Basically there is a new idle table the PCM looks to (which is a target RPM) when you are moving and put the gear selector in 'N'. I don't think they have an Idle table when moving and you shift to 'P' :)

Cheers,
Ross

[daveb]

excellent,

[curtbriggs]

[quote="daveb"]I have heads/cam etc in my car, finished last week. I have the idle very good with once weird exception.

If I put the car in Neutral whilst moving it hunts all around for a steady idle rpm. Quite wildy 600-1700 rpm at times. I have logged this and what is happening is the AFR is going from rich to lean, 11-17:1.

I almost never put it in N whilst moving anyway, but I have the car idling perfect and this anomaly has me stumped.

When the car comes to a stop, the idle speed immediately locks on to the correct speed.

What mode is it in whilst it is not at rest? And why would the AFR be all over the place?


Dave, I had the same problem after I installed a cam.
In Tune, Engine calibrations, Idle, double click on "Desired Idle Speed", there are four columns under Conditions, labeled:
In-Gear A/C on, In-Gear A/C Off. In P/N A/C On, In P/N A/C Off.
Note: The scale on the left is engine coolant temperature, not outside air temp.
I had set the idle speed in the two columns on the left and when rolling with the clutch in, the idle dropped back to a rolling low setting. Set the idle speed in all four columns for the engine operating temperature range. I started at 1000 RPM for a cold engine and went to my desired 910 RPM for normal operating temperatures for my 160* TStat. I would set the normal speed 10-20 RPM high in the two right columns.

Note: An easier, faster way is to use the two graphs above the four columns, right click and drag the cursor to the new idle speeds curve that you desire. Do both graphs. Double check for the correct idle speed for your normal operating temperature in the four columns below and adjust if necessary.

Cheers, Curt