TurboRaider Posted November 12, 2002 Report Share Posted November 12, 2002 Kevin, what year is the ECU you are looking at? Sig, What year is the ECU I have? (88?) The circuit I have is vastly different. Pin 21 goes to a 100k to ground, also through a 4.7 k, to the E or C of what is probably a transistor.. it says M317Z...didnt find it after a quick search. (I'm a little reluctant to dissassemble Sigs ECU to see if its NPN or PNP). What I also found is that transistor's base goes to the C(E) of another transistor whos E© goes to a 5V pullup and the base goes to the output of an opamp through a 4.7k. Perfect setup to drive the line. But the kicker is this.  The Original pin, after it goes through the first 4.7k (also has a .47uf to ground) goes to another 4.7k and to the input of an A/D converter. (Pin 3 of a Toshiba TC35095P) Still sure it's not going to work? Regards, Mike Montalvo digital tuning, inc. www.pocketlogger.com Mike, Very happy to see some real tech discussion! My ECU is an 88. The transistor that I ohmed out that pin 21 connectors to is labled Q4.  I have a jpg of the ECU that I can send you a tonight ...  I will mark it up with my interperation of the circuit. The picture given in the book for the pin and function for the connector to the ECU shows the cable side of the connector so you have to flip the pin and functions on the diagram to find pin 21. Pin 21 does not go to the thick film hybrid (as would be the case if the image in manual was for the ECU connector and not the cable). As far as q4 goes......  the 470 Ù is a wire wound (looks to be around 1/4 watt).  The 10 k is a ceramic and is 1/8 watt. Q4 is not the typical transistor as far as its pin and function.  The center pin is the collector.  This had me fooled for a while.  Pin 3 is the base leaving the power connected to the emmiter (pin1).  It does appear to be a standard PNP. The also is a 10k across the emmiter and the base on mine.  This base is connected to an IC labeled 647000.  The manf of the IC is Mitsubishi. I also noticed when checking the circuit out that the trace from the 470 Ù resistor to the transistor that the run goes under a component and is hard to find where it goes....  I pulled the PCB off the the base and verified it by looking at the back side of of the board.  The run crosses over to the other side of the PCB (side with the other connector). I feel pretty confident that I did not make any mistakes on this, however it would be great for not to just take my word for it and verify my fidings. Also there is the remote chance that not all ECU's were the same in the same model year. The best way to test a hypothises is through indepentent verification. Best Regards, Kevin C Link to comment Share on other sites More sharing options...
SiG Posted November 13, 2002 Author Report Share Posted November 13, 2002 Mike The ECU you have is out of a "88 Conquest. Feel free to open it and do what you need with it! Sig Link to comment Share on other sites More sharing options...
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