1227165 Tuning Advice

[Bruce Wilcox (EUS)]

Hi Mark,

I compared the stock chip BIN with the ASM bin. No changes were made in the
code area. Updates were implemented only in the tables.

As discussed earlier, at WOT the BLM & INT jump to 128. Since the system is
somewhat rich at part-throttle conditions does this mean,

1. 
The computer pulls fuel out at WOT (resulting from BLM <= 128 @ part
throttle). End Result : lean

2.
The computer does not implement a BLM compensation at WOT. End Result : lean

Can I look in the lookup tables or code to find out if BLM based WOT
compensation exits??? If so, please send the information to me.

One clue supporting the lean theory exists in the BLM data that I posted. I
managed to record some closed-loop part throttle BLM Cell 14 & 15 data. The
RPM range was 2200 - 2500 and the LV8 range was 167 - 180. The BLM was 123
and the INT range was 136 - 143. This indicates that a fair amount of fuel
was added to the base map.

For a typical TPI system, what is the maximum obtainable fuel pressure???
Presently, my fuel pressure is adjusted for a 44 PSI idle and 50+ PSI WOT
condition.

I have a general MAF fuel mapping question for you. If the BLM is all over
the place (above & below 128 for various RPM & load conditions), does this
indicate that the engine VE is different than the data in the Injector PW vs
RPM vs Load table ???? Does this table use "Load" or "LV8" ??? I am
suspicious that this table is slightly off. If I increase the FP to
compensate the WOT condition, then I would expect the part-throttle BLM
numbers to drop down even more. Presently, they dip down to 110!

I will play with the FP and base timing initially, but I do not believe the
engine will be optimized over the entire operational envelope. If I decrease
the base timing, the part 
throttle response will most likely suffer. As the FP is increased, the part
throttle BLM will decrease. 

The goal is to center the part throttle BLM and stop the WOT knock count
generation.

Thanks for the Advice,

Bruce

	 From:	Mark Romans [SMTP:romans at pacbell.net]
> Sent:	Friday, April 23, 1999 12:59 AM
> To:	gmecm at efi332.eng.ohio-state.edu
> Subject:	Re: 1227165 Tuning Advice 
> 
> Also with a stock chip, the ecm will add an amount of fuel to WOT that it
> adds to part throttle, if however it is pulling fuel out, it will revert
> to
> BL of 128 at WOT.
> Mark
> -----Original Message-----
> From: Bruce Wilcox (EUS) <EUSBEW at am1.ericsson.se>
> To: 'gmecm at efi332.eng.ohio-state.edu' <gmecm at efi332.eng.ohio-state.edu>
> Date: Thursday, April 22, 1999 12:14 PM
> Subject: RE: 1227165 Tuning Advice
> 
> 
> >Hi John,
> >
> >I think the ECM is learning over time. The long term BLM is low (110) but
> >the short term integrator is around 128. I believe this indicates that
> the
> >ECM has compensated.
> >
> >Bruce
> >
> >> -----Original Message-----
> >> From: jgwynne at mrcday.com [SMTP:jgwynne at mrcday.com]
> >> Sent: Thursday, April 22, 1999 11:35 AM
> >> To: gmecm at efi332.eng.ohio-state.edu
> >> Subject: Re: 1227165 Tuning Advice
> >>
> >>
> >>
> >> | > 1.
> >> | > The nominal BLM is consistently below 128. Depending on the exact
> BLM
> >> | cell,
> >> | > the nominal value approaches 110. The integrator hovers around 128
> +/-
> >> 5.
> >> | > Since the BLM is low and the integrator is OK, my guess is the fuel
> >> | pressure
> >> | > is high (44 PSI @ idle, 50+ PSI @ WOT). Is this a reasonable
> >> diagnoses??
> >> |
> >> | Have you run any performance base lines?..  Fuel Pressure makes a ton
> of
> >> | difference at WOT..  Find out where your at with WOT AND cruise, then
> >> judge
> >> | where you need to move things.  (Also, measure PW/Duty cycle).
> >>
> >> Why does fuel pressure make a ton of difference at WOT? The ecm should
> >> learn a correction for pressure while in closed loop that is applies to
> >> the open loop WOT. Changing fuel pressure would allow injects to flow
> >> more if needed, but the ecm should, over time, learn the correction
> >> factor for the pressure being used. yes?
> >>
> >> john
> >