1227165 Tuning Advice

[Mark Romans]

They may already be zero'd for an automatic trans app anyway.
-----Original Message-----
From: Bruce & Lisa Wilcox <wilcoxbl at gte.net>
To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
Date: Saturday, April 24, 1999 10:00 AM
Subject: Re: 1227165 Tuning Advice


>HI Mark,
>
>My car uses the 1227165 ECM (87 IROC: MAF TPI setup) and I have not found a
>WOT Spark Adder table. Could you send me the table address???
>
>Presently, it looks like my knock-count problem is the result of spark
>timing and a slightly lean condition. I increased the fuel pressure to 48
>PSI @ idle (56 PSI, no vacuum on the AFPR diaphragm). The original AFPR
>setting was 42 PSI at idle (52 PSI, no vacuum). The test results indicated
>that car pulled MUCH stronger and the knock counts were significantly
>diminished. I can run WOT from 1500 RPM to 5500 RPM in 3rd and 4th gear
>without any knock-counts. I still get knock counts in 1st and 2nd gear.
From
>my calculations, it looks like the injector flow rate changed 3.8%. Maybe
>the flow rate change was not enough or the timing to advanced to far.
>
>The plan is to set the base timing back to 6° BTDC and adjust the fuel
>pressure for a nominal part throttle BLM of 128 +/- 10. The WOT A/F ratio
>will be adjusted with the "PE A/F % change vs. RPM" table.
>
>If the part-throttle response gets worse as I decrease the base-timing, I
>can add it back in  the timing table.
>
>Thanks Again and Best Regards,
>
>Bruce Wilcox
>
>-----Original Message-----
>From: Mark Romans <romans at pacbell.net>
>To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
>Date: Friday, April 23, 1999 10:39 PM
>Subject: Re: 1227165 Tuning Advice
>
>
>I agree the spark map should be changed, I am just saying try putting the
>original initial advance back in for a quick dirty check.  Also if you ever
>have to get your car smogged they will check the initial advance, so change
>the map and set the intitial back to stock at the distributor and change
the
>timing in the chip.
>On my car LV8 is "Calculated Load Value"  When I tried to reference
>grams/sec, rpm and the spark map, nothing worked.  When I use LV8, it
>matches up perfectly.  (Except when you have a WOT spark adder)  Which I
>would zero out.
>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: Friday, April 23, 1999 5:48 AM
>Subject: RE: 1227165 Tuning Advice
>
>
>>Hi Mark,
>>
>>Could you elaborate a little more on why the base timing change would
>work??
>>The part throttle operation is great. No knock counts anywhere in the
>>operation envelope. The problem seems to occur at WOT high LV8 loads (>=
>>240) and RPM's >= 3000. Bruce Plecan thinks that WOT total advance in the
>>28° - 32° range is reasonable. From the Diacom data + 4° extra base timing
>>advance, the total advance calculates to 22°.  This number seems very
>>reasonable. However, I will try your suggestion.
>>
>>What is the difference between the "load" parameter and "LV8"??  I see
>>references to both.
>>
>>Thanks and Best Regards,
>>
>>Bruce
>>
>>> -----Original Message-----
>>> From: Mark Romans [SMTP:romans at pacbell.net]
>>> Sent: Friday, April 23, 1999 12:57 AM
>>> To: gmecm at efi332.eng.ohio-state.edu
>>> Subject: Re: 1227165 Tuning Advice
>>>
>>> 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?!
>>> >> ===========================================================
>>> >
>>
>
>