pcmhacking.net

Hi,
In reference to a 2002 Vx V6 3800 na engine.

I can't seem to find where I can adjust the AFR when the car is going from cold start up to running temperature while idling.

Obviously it is in Open Loop mode, but there doesn't seem to be any adjustment table for that range.
With a snap shot from a log, it shows AFR 11.7 while at Engine Coolant of 20.8 deg Celcius. The AFR seems to increase with temp, so it seems there is some table causing it? Or maybe it's outside the TunerPro accessing locations?

My tables of Open Loop AFR Vs MGC Vs RPM have AFR values all above 14.00.
Open Loop Idle AFR Vs Engine Temp has AFR values 14.12 and above.

Either i am not seeing a table for the adjustment, or could things like the Default Airflow Vs RPM & TPS% have anything to do with the AFR at Idle?
Also could things like End of Injection Target Vs Coolant Temp have anything to do with the AFR during idle?

I am a little bit lost here as to why it is so rich on the AFR at cold engine conditions.

What XDF are you using?

It will just be your normal cold start enrichment decay tables are at play. This is normal to aid cold starts.

"could things like the Default Airflow Vs RPM & TPS% have anything to do with the AFR at Idle" - No - these are only there as a sanity check for MAF and or backup should the MAF fail

"Also could things like End of Injection Target Vs Coolant Temp have anything to do with the AFR during idle?" - No EOI is just as it sounds, The target degree at which the injection pulse should have finished by. Good for moving EOI on cammed motors with large overlap to help keep more injector pulse in the cylinder and less being forced out the open ex valve at idle.

Doesn't look like after start enrichment decay values are defined in the flash pcm xdf anyway. Not something you'd generally have to touch

hsv08 wrote:Doesn't look like after start enrichment decay values are defined in the flash pcm xdf anyway. Not something you'd generally have to touch

Hi hsv08,

Thanks for the feedback. I am using the following xdf and adx files:
VX_V6_$BD_Enhanced_v0.9e.xdf
VX_V6_$BD_Enhanced_v0.9c.adx

I am relatively new to all the tuning stuff. I am not sure what the Decay tables are or what there values do. The "PE Decay Rate (SEC)" currently is set to 0.10, "Decel - Multiplier Decay Vs Reference Counts" & "AE - Multiplier Decay Vs Reference Counts" are all values from what i believe from my original unchanged PCM bin file.

With the "End of Injection Target Vs Coolant Temp", that makes sense as to what it means now, but why on earth would they have the value 408.46 Crank Deg ?

I have noticed that at cold and idle the car has a excessive smell of rich fuel from the exhaust. When i use the dash to see the idle fuel consumption it can start at as high as 5L/hr then decrease as temp rises to around 2.0 L/hr at idle. This is higher than it used to be before. At idle i could see it as good as 1.2L/hr. i am suspecting that the Injector Base Rate of 361.33msec/gram is not correct for the injectors of my car. Which is causing too much fuel to be delivered. How I do that exactly is uncertain at this stage. I suspect too much fuel by injector inaccuracy as there are a few variants of specs for the same Bosh injectors on the internet and what the service manual says. for example:
Service manual says:
BOSCH0-280-155-777 LBS/HR14.25 CC/MIN149.8 GRAMS107.7 PSI43.5 BAR3.
Internet#1 says:
BOSCH0-280-155-777 LBS/HR21.44 CC/MIN219.85 GRAMS162 PSI- BAR3.5.
Internet#2 says:
BOSCH0-280-155-777 LBS/HR26.35 CC/MIN276.9 GRAMS199.2 PSI- BAR-.

The crank does 2 full rotations to complete the 4 cycles so in terms of valve events there are 720 degrees of crankshaft rotation.

immortality wrote:The crank does 2 full rotations to complete the 4 cycles so in terms of valve events there are 720 degrees of crankshaft rotation.

Ok, that makes logical sense now. thanks for clearing that up.