TECHNICAL NOTES ON THE EEC-IV MCU - Auto diagnostics

firing order. It is an 8 x 1, one byte, unsigned binary value.
50
40
30
20
10
0
L
O
A
D
%
Eectch98-Part2.fm
The Base Spark Timing Table is stored at 7574 (30068 decimal) as unsigned byte values.
Divide by 4 to convert to decimal.
L
O
A
D
%
500
700
The Altitude Base Spark [Deg BTDC] table lives at 75C4 (30148 decimal) as one-byte, unsigned
EEC-IV Technical Notes: Software 30 last edited: 9/29/98
RPM
500 700 900 1100 1300 1500 2000 2500 3000 4000
75 11.50 11.50 13.00 13.00 15.50 18.25 23.50 27.25 27.25 27.25
60 11.50 14.25 14.25 14.25 17.00 19.50 27.25 27.25 27.25 27.25
50 17.25 17.25 18.50 18.50 20.75 23.00 26.50 31.25 31.25 31.25
40 23.00 24.25 28.75 32.25 35.75 37.00 38.00 39.00 32.25 32.25
30 28.75 30.00 32.25 33.25 37.00 37.00 43.75 46.00 32.25 32.25
23 28.00 28.00 33.00 41.50 41.50 42.75 43.75 43.75 32.25 32.25
15 28.00 28.00 28.00 31.25 33.25 34.25 34.25 34.25 28.25 28.25
05 28.00 28.00 28.00 27.25 29.00 30.00 30.00 30.00 30.00 30.00
Table 26: Base Spark [Deg BTDC]
900
1100
1300
1500
RPM
2000
2500
3000
500 700 900 1100 1300 1500 2000 2500 3000 4000
75 11.50 11.50 13.00 13.00 14.25 17.00 27.25 27.25 27.25 27.25
60 11.50 11.50 13.00 13.00 14.25 18.25 27.25 27.25 27.25 27.25
50 17.25 18.50 18.50 18.50 20.75 23.00 30.00 31.25 31.25 31.25
40 23.00 24.25 28.75 37.00 39.00 39.00 38.00 37.00 32.25 32.25
30 28.75 30.00 34.50 42.75 43.75 41.5 41.5 43.75 32.25 32.25
23 28.00 28.00 33.00 42.75 42.75 43.75 43.75 43.75 32.25 32.25
15 28.00 28.00 28.00 32.25 34.25 35.25 35.25 34.25 28.25 28.25
05 28.00 28.00 28.00 27.25 29.00 30.00 30.00 30.00 30.00 30.00
Table 27: Altitude Base Spark [Deg BTDC]
4000
75
60
50
40
30
23
15
5