1227165 Tuning Advice

[Mark Romans]

Try putting the initial advance back to stock and recheck it without
changing anything else.
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 11:43 AM
Subject: RE: 1227165 Tuning Advice


>Thanks Dave,
>
>I looked at the diacom+ WOT data.
>
>2000 <= RPM <= 5500
>
>1st Gear: minimum retard = 5.8° , maximum retard = 9.7°
>2nd Gear: minimum retard = 4.8° , maximum retard = 10.2°
>3rd Gear: minimum retard = 7.2° , maximum retard = 12.5°
>
>I think the EPROM tables should be modified. What is your opinion??
>
>Thanks and Best Regards,
>
>Bruce
>
>
>
>> -----Original Message-----
>> From: David A. Cooley [SMTP:n5xmt at bellsouth.net]
>> Sent: Thursday, April 22, 1999 7:49 AM
>> To: gmecm at efi332.eng.ohio-state.edu
>> Subject: Re: 1227165 Tuning Advice
>>
>> At 01:36 PM 4/22/99 +0200, you wrote:
>> >Hi,
>> >
>> >Presently, I am trying to optimize the ECM tuning. The application is a
>> MAF
>> >87 TPI Camaro with a moderately modified 355 CI (aluminum heads) motor.
>> >
>> >There are two minor problems.
>> >
>> >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??
>> >
>>
>> Is this at idle or in all blm cells?
>> If it's all, then dropping the FP to 37-38 psi Idle may be a good
place...
>> 110 is low, but not out of range for the ECM.
>>
>> >2.
>> >The knock sensor triggers during extended WOT test runs (hard to hear
any
>> >audible effects). Given a WOT test run through the first three gears
(RPM
>> >range: 2000 - 5500 RPM), the knock counts go up roughly 13 - 15 counts.
>> Part
>> >throttle "closed loop" conditions perform great (no knock & excellent
>> >performance). I would like to eliminate the root cause of the additional
>> >knock counts. Since the "closed loop" part throttle performance is
>> >excellent, I do not want to back off the base timing ( 10° BTDC). My
>> guess
>> >is the spark table needs modification. Any comments or suggestions are
>> >appreciated.
>>
>> A "tickle" to the knock sensor with no audible knock means you are
running
>> the max for your fuel/engine combo...  What you really need to look at is
>> knock retard degrees and see what it says.  Knock counts on my 95 lesabre
>> start at 0 when the key is turned on, but the engaging of the starter to
>> the ring gear causes 10-15 knock counts as you crank...  If Knock retard
>> is
>> less than 2 degrees at WOT, your timing is just fine.
>> ===========================================================
>>            David Cooley N5XMT           Internet: N5XMT at bellsouth.net
>>      Packet: N5XMT at KQ4LO.#INT.NC.USA.NA   T.A.P.R. Member #7068
>>    Sponges grow in the ocean... Wonder how deep it would be if they
>> didn't?!
>> ===========================================================
>