[Diy_efi] Re: IAC Counts and EGR during tuning

[Mike Frels]

After my last round of VE changes and driving for scan data the idle has 
settled down. It's now only at 11. This is closest enough to 10 to clear up 
that concern.

My injector constant in the AUJP is already set to 23.something or other 
for the #24 injectors. Last drive and scan showed improvement but as is 
usual with every good change comes something puzzling again. With my high 
RPM/high kPa VE values in the 90s when dip into these higher kPa 
ranges(without going into PE) my BLMs come down into the 130s. My low VE 
tables are still keeping me way lean. For example sitting at idle with my 
VEs in the low 80s my BLMs are still at 160 with long term fuel trim of 
125%. The VE adjustment necessary to get me to 128 would push a good range 
of VEs into the 100s...????...I have a hard time believing these Vortec 
heads and SDPC TPI intake are THAT efficient to require that much fuel. I 
am starting to wonder if I need to move to #30 injectors.

Thoughts, comments?

Sorry for not mentioning it earlier but this setup is in an 80's manual 
tranny Camaro.

Happy Holidays,
Mike

At 09:05 PM 12/30/2004, you wrote:
>I would definitely disable EGR while tuning the VE tables.  I also like to 
>disable DFCO and Highway Fuel Mode.  Any one of these 3 will throw your O2 
>readings off when they come into play, which messes with the INT and BLM. 
>It might also be a good idea to play with the injector constant to get the 
>BLMs a little closer before you start to tweak in the VE.
>
>Also, those are pretty high IAC counts for idle.  You may have something 
>dirty/clogged blocking your airflow (clean the throttlebody just on 
>principle) or your "minimum airflow" setting is off.  I shoot for 10 
>counts at hot idle in gear.
>
>That MAT reading is pretty reasonable.  The sensor is made just like a 
>coolant sensor (solid brass) and it soaks up a lot of heat from the 
>aluminum intake.  AFAIK it's only used to enable EGR, and possibly for a 
>fuel trim modifier in AUJP.
>

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