{B3647} Open loop AFR

[BowlingSS]

Correct Andrew, the values need to be minimised.

Cheers,
Ross

Thanks guys.

Bill

[87gmc]

Hey Ross question on the afr vs rpm table.

I have it tuned lean in lets say crusing speed areas. My question is does it hurt the engine to accelerate lean, i notice im hitting areas of lean such as 15.5 when im picking up speed and this areas that usually you cruise.

I look at the lean cruise table and notice it has to meet certain speeds and time to come into play. Is this for EPA standards or for hurting engine standards?

Oh yea #3 custom kicks A@#

[Chris81]

Any ideas on how to get a good idle in cold weather with B3647? Is there something i'm missing in the idle tables?

I'm assuming it is doing this for one b/c the AFR is leaner at startup and two.. B4108 is disabled. What do I do?

Or, should moving say 400-1600 rpm, 20-40 kPa richer than 14.63 fix the problem?

My car wouldn't idle at all this morning in 40 degree weather.. the IAC was going crazy.. lol

[GMPX]

Hey Ross question on the afr vs rpm table.

I have it tuned lean in lets say crusing speed areas. My question is does it hurt the engine to accelerate lean, i notice im hitting areas of lean such as 15.5 when im picking up speed and this areas that usually you cruise.

I look at the lean cruise table and notice it has to meet certain speeds and time to come into play. Is this for EPA standards or for hurting engine standards?

Oh yea #3 custom kicks A@#

When my car was stock I monitored the AFR's in lean cruise and it went well into the 16's, look at the settings in a Holden file, they run like that even up to about 0.50g/cyl.

Before I had an LS1 I drove another Holden fitted with a 5L V8, on that car I changed the lean cruise settings to kick in very fast, like a 5 second delay.

The timers/ speed settings are in there so lean cruise should only kick in when you are out on the highway, with fuel prices these days you can bet any Holden owner with a tuning tool has changed that. I suspect for sure that is for emissions compliance. In fact I would say in Australia the cars are not tested at those speeds or for 60 seconds only.

So in summary, only going out to 15.5 should be fine, afterall, I thought 14.7 was just the AFR the cat converter operated at it's maximum efficency.

Cheers,
Ross

[Chris81]

Any ideas on how to get a good idle in cold weather with B3647? Is there something i'm missing in the idle tables?

I'm assuming it is doing this for one b/c the AFR is leaner at startup and two.. B4108 is disabled. What do I do?

Or, should moving say 400-1600 rpm, 20-40 kPa richer than 14.63 fix the problem?

My car wouldn't idle at all this morning in 40 degree weather.. the IAC was going crazy.. lol

All good now, A0008 fixed it.

[GMPX]

Any ideas on how to get a good idle in cold weather with B3647? Is there something i'm missing in the idle tables?

I'm assuming it is doing this for one b/c the AFR is leaner at startup and two.. B4108 is disabled. What do I do?

Or, should moving say 400-1600 rpm, 20-40 kPa richer than 14.63 fix the problem?

My car wouldn't idle at all this morning in 40 degree weather.. the IAC was going crazy.. lol

Chris,

Assuming the idle tables are O.K, you need to monitor what your commanded AFR is, if it is 14.63 then you have other issues, if it is 11 then yeah, probably too rich.
Do you have a WBO2 you can confirm the AFR's with?.

Cheers,
Ross

[87gmc]

Hey Ross question on the afr vs rpm table.

I have it tuned lean in lets say crusing speed areas. My question is does it hurt the engine to accelerate lean, i notice im hitting areas of lean such as 15.5 when im picking up speed and this areas that usually you cruise.

I look at the lean cruise table and notice it has to meet certain speeds and time to come into play. Is this for EPA standards or for hurting engine standards?

Oh yea #3 custom kicks A@#

When my car was stock I monitored the AFR's in lean cruise and it went well into the 16's, look at the settings in a Holden file, they run like that even up to about 0.50g/cyl.

Before I had an LS1 I drove another Holden fitted with a 5L V8, on that car I changed the lean cruise settings to kick in very fast, like a 5 second delay.

The timers/ speed settings are in there so lean cruise should only kick in when you are out on the highway, with fuel prices these days you can bet any Holden owner with a tuning tool has changed that. I suspect for sure that is for emissions compliance. In fact I would say in Australia the cars are not tested at those speeds or for 60 seconds only.

So in summary, only going out to 15.5 should be fine, afterall, I thought 14.7 was just the AFR the cat converter operated at it's maximum efficency.

Cheers,
Ross

Just wanted to make sure if i dont hurt the engine. Didnt know if it was coming at certain speeds for a reason of hurting the engine or some kinda of law other countries have