(749)
With a BPC vs EGR setting of 0.13 (PromGrammer) or 190.00 (TP), my BLMs were 112-117 at idle. Adjusting this value to 0.11 with a Romulator and TC yielded idle values of 128-130.

What I found interesting is my EGT used to read in the 1150 F range. Now, it's in the high 900's. This IS exactly what my EGTs were before prior to converting from the 165 to 749.

My question is if the ECM is adding or subtracting fuel as necessary to achieve a specific A/F ratio, why are EGTs different when adjusting this constant?

This leads me to my second question. My 749 spark advance table values are not as aggressive as the 165 table values. With the 165, I ran 30-32 degrees advance at idle. With the 749, it's around 23 degrees. I have yet to tinker with this table. Should I run more advance, say like with the 165? Are there any disadvantages to doing this? What are you guy's running?

 

There was another post similar to this a week ago. On many of the stock GM bins I seen, idle tends to be around 24* (+/-2*). This is when fully warmed with no other bias kicking in.

It may be, your 165 was too high.

 

Spark and fuel work together to form you indicated AFR. Retarding the timing will generate a false rich, since the fuel isn't allowed enough time to burn fully.

And the 165 tables are based on LV8 so, all might not be as it appears, at a glance.

Min amount of timing that makes the engine happy.
IMO, 23 is alot more resonable for idle, then 32d.

 

is that 23deg in the bin or scan results?

Some prg. (TTS) only put out what the ECM adds? So 23deg in the TTS file is 23deg+base timing at the crank...

There is also a table "timing vs MAT" that takes out 1.8 deg all the time...


/N.

 

When I refer to 23-24*, I am talking about total timing. So if you only working with the "relative timing", then you would need to account for the base.

 

Willie,

What size injectors are you running for the .13 setting? I'm still trying to get my car tuned in with 42 lb green top injectors, still too rich right now.

pj

 

In PromGrammer mines at .071 with ford 42Ib green tops, seem to do the trick.