PT3-A04 ECU Hacking

Removed the EPROM

Jul 20, 2010:
I got the EPROM removed from the board without destroying the board or the EPROM. I don’t have a hot air station. So I used CO2 cartridges and a soldering iron. Unfortunately compressed air sprays solder everywhere. If you attempt to do this be warned that although it may seem like a good idea to clean solder off the board with alcohol, it isn’t. Whatever coating they put on there combined with alcohol makes a huge sticky mess.

Next I have to figure out how to read the EPROM. I have access to an old EPROM programmer. Unfortunately the computer that has the software for the programmer has been sitting out in the garage for a long time and when I turn it on all it does is beep. So I am going to have to make my self a reader for it.

Added Header to ECU

Jul 21, 2010:
I got the headers added and a design for the board I am going to make. Had some difficulty getting the headers in because of residual solder. I had a dremel drill bit that was exactly the right size and used it with a wrench to clean out most of the holes nice. Until I accidentally flung it across the room from the tension between the board and the wrench. I then tried using the bigger drill bit from the dremel set which tore off one of the pads. Luckily it was a pad that nothing went to so everything should be okay. I finished off by putting the remaining header in the holes and wiggling it as I heated each of the 3 holes that I didn’t get to finish with the drill bit.

The board I intend to make for it has 2 sockets. One is for an EPROM and one is for an EEPROM the pinouts are slightly different. So I figured I would put both on the same board to make life easier for me. It won’t be able to use both ROMs at the same time however I may decide to add a switch to easily switch between the two ROM sockets so both ROMs can be on board at the same time.

Finished the ROM Module Board

Jul 23, 2010:
I got my ROM module built. I tested the ECU in the car and everything seems to be working. The module is shorter than the height of the ECU and the cover can be put back on. The clearance is close so if you attempt this don’t buy really tall sockets you might not have clearance.

Eprom Emulator

( Pictures to come )

Jan 23, 2011:
I was contacted in regards to the Accord ECU. We have made some progress so I made my self an Eprom Emulator. Currently it is untested but hope to get that taken care of soon.

I could just buy a Series 2 EMS for Accord 2.2L 1990-1995 AEM Part# 30-6040 for $1,260.00. However, that seems a bit excessive.

Data Tables

Fuel Map?
Spark Advance Table?


AMP MultiLock 040/070 Hybrid 16 Position Plug Housing{38,42,54,64,76}
AMP MultiLock 040/070 Hybrid 22 Position Plug Housing {34,38,48,64,76}
AMP MultiLock 040/070 Hybrid 26 Position Plug Housing {26,38,42,48,54,64,76}
AMP MultiLock 040II Contact 22-18 AWG Copper / Pre Tin
AMP MultiLock 070II Contact 20-16 AWG Brass / Pre Tin
AMP MultiLock 040/070 Hybrid 64 Position Receptacle (Cap)

Gage Cluster Connectors (Find a source for these)

Online Components Also Carries Parts



PGM-FI ECU: A1 Injector 1 -> Darlington Line Driver Pin 7
PGM-FI ECU: A2 Injector 4 -> Darlington Line Driver Pin 10
PGM-FI ECU: A3 Injector 2 -> Darlington Line Driver Pin 6
PGM-FI ECU: A5 Injector 3 -> Darlington Line Driver Pin 3

M66911 Pin 30 -> XTL1 Pin 1
M66911 Pin 31 -> XTL1 Pin 2
M66911 Pin 32 -> GND
M66911 Pin 62 -> GND

IC1 C Pin 9 -> IC2 C Pin 9 -> Red Red Red Resistor -> IC3 P4.3 Pin 49
IC1 B Pin 10 -> IC2 B Pin 10 -> Red Red Red Resistor -> IC3 P4.2 Pin 48
IC1 A Pin 11 -> IC2 A Pin 11 -> Red Red Red Resistor -> IC3 P4.1 Pin 47
IC1 INH Pin 6 -> IC2 INH Pin 6 -> Ground
IC1 X Pin 3 -> IC3 AI7 Pin 61
IC2 X Pin 3 -> IC3 AI6 Pin 60

Crank Sensor
RPM Calculations
Injector Timing
TDC Sensor
Start up Injector Timing
Cylinder Sensor
Position of Cylinder

Run line from Crank Sensor to PIC Parallel System
Determine RPM from Crank Sensor

16×2 LCD
S160 R12500 F100
T120 O123456.6

Write Odometer to Internal EEPROM every 15 seconds if it has changed.
Read Coolent Temperature
Read Fuel Level
Read Speed Senser
Interrupt on crank position.