Andy's 1996 GM 3.1L V6 in a 1932 Ford Coupe (11th)

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DeuceEFI
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Re: Engine #11 Andy's 1996 GM 3.1L V6 in a 1932 Ford Coupe

Post by DeuceEFI »

VE Map from MS2 (best tune for performance with bank injection)

Ignition Map based on GM original ignition tables.

EDIT: the spark advance table is incorrect see the .txt file in the next post for the correct timing information... 03/27/2012
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MS2_VE_Table.PNG
MS2_IgnitionTable.PNG
Last edited by DeuceEFI on Wed Mar 28, 2012 2:50 am, edited 1 time in total.
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DeuceEFI
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Re: Engine #11 Andy's 1996 GM 3.1L V6 in a 1932 Ford Coupe

Post by DeuceEFI »

Here is a text file with the original GM ECU tables.
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[The extension txt has been deactivated and can no longer be displayed.]

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Re: Engine #11 Andy's 1996 GM 3.1L V6 in a 1932 Ford Coupe

Post by DeuceEFI »

Here is the waveform after inverting the EST signal coming out of the XOR.

Green trace is Reference Pulse into FreeEMS, Blue trace is EST from FreeEMS.
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After inverting the XOR output for EST (blue trace)
After inverting the XOR output for EST (blue trace)
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Re: Engine #11 Andy's 1996 GM 3.1L V6 in a 1932 Ford Coupe

Post by DeuceEFI »

Photos from my testing today...

Here is the first round of testing with changing only the dwell.
After the dwell was increased to 15000 the engine became harder to start and rocked violently.

I also included the baseline factory TACH versus EST waveforms...

Notice the 1500Dwell_0Offset.png the EST signal is inverted...
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GM Factory DIS EST signal at idle (blue trace)
GM Factory DIS EST signal at idle (blue trace)
15000Dwell_0Offset.png
1500Dwell_0Offset.png
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Re: Engine #11 Andy's 1996 GM 3.1L V6 in a 1932 Ford Coupe

Post by DeuceEFI »

After inverting the EST signal, here is what I have come up with...

For these only the dwell has been changed.

Timing light shows 14* advance versus MTX 10* advance.
Attachments
15000Dwell_0Offset_inverted.png
7000Dwell_0Offset_inverted.png
1500Dwell_0Offset_inverted.png
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Re: Engine #11 Andy's 1996 GM 3.1L V6 in a 1932 Ford Coupe

Post by AncientGeek »

I believe its been fixed, but before anyone tries to copy it, lets place on record that that spark table is about as wrong as its possible to be.
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Re: Engine #11 Andy's 1996 GM 3.1L V6 in a 1932 Ford Coupe

Post by DeuceEFI »

This post contains a Saleae trace of the original GM Reference Pulse and EST signal for idle plus a couple of revs from my other car that still has the factory ECU.
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GM_Factory_ReferencePulse_vs_EST.logicdata.zip
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Re: Engine #11 Andy's 1996 GM 3.1L V6 in a 1932 Ford Coupe

Post by Fred »

Good info! Take a look at the EST pulses between 18.02002542 and 18.07987475.

With respect to timing:
  • The ignition right on 30ms is 1.48ms before the rising edge of the reference pulse.
  • The ignition just before 50ms is 1.72ms before the rising edge of the reference pulse.
  • The ignition right on 60ms is 1.85ms before the rising edge of the reference pulse.
  • The ignition just before 80ms is 1.96ms before the rising edge of the reference pulse.

All of these are at about 1300 RPM with 45ms per revolution which means that the four pulses were 12, 13.8, 14.8, and 16 degrees BTDC, respectively. And all of that over 4 reference pulses and 480 degrees of engine movement. The dwell was also wild with 5.18, 5.58, 5.49, and then suddenly 6.92 followed by another 6.92 and then a 6.48. Not very consistent with the leading edge of the dwell falling fairly randomly and not mattering much. Three sample points:
  • Dwell at idle of 895 rpm is about 6ms with 4.5 degrees BTDC timing which is 25% duty.
  • And 5ms with 70% duty and 12.8 degrees BTDC timing at 2142 rpm
  • And 4.6 with 70% duty and 25 degrees BTDC timing at 3000 RPM
I'll try to configure you something on based on the latest stuff later today, after i get the config clean up stuff out of the way, and get it looking right on my bench rig. Then if you have the XOR setup correctly, you'll get good results. I hope.

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Re: Engine #11 Andy's 1996 GM 3.1L V6 in a 1932 Ford Coupe

Post by Fred »

Pushed on new branch "ForAndyToTryAndTweak" which I'll amend based on your detailed and thorough report :-)

From IRC, for the record:

(15:56:24) DeuceEFI: to be clear you want RPM, CAM inputs along with Ignition Advance outputs from both the OEM and FreeEMS from idle to 5k in nice steps, right?
(15:57:16) Fred: sounds idyllic, yes :-)

A before (my attempt) and after, with your tuned results, would be good :-)

Things to tweak: Dwell and timing, both can be live edited in EMStudio, but NOT MTX.

(16:00:18) Fred: you've also got the decoder offset that you can adjust if it's wildly out, and polarity of output and input, the latter of which is the same as the decoder offset, just more coarsely

Don't forget to hit save on your table changes, whatever they are, and get me those details. Somehow.

Fred.
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Re: Engine #11 Andy's 1996 GM 3.1L V6 in a 1932 Ford Coupe

Post by BenFenner »

AncientGeek wrote:I believe its been fixed, but before anyone tries to copy it, lets place on record that that spark table is about as wrong as its possible to be.
:lol2:
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