1G Desktop ECU tuning

[NineThrityONE]

I just got a DSMLink ECU and the cable that came with it (Keyspan serial converter) I am trying to make changes before I plug it into the car since I was told it was set up for MAP, and larger injectors.

I used a motorcycle battery and gave + power to pins 107 and 102, and -(neg) connect to 106 and 101.

The computer/cable was connected to pins 1 and 2. However there was one more wire; the ground, which I did not connect (want to be super careful and not short out the ECU) You can see here in the picture.
Do I just also connect this to the - neg of the battery? Since it is stated as it normally goes to chassis ground?

Currently the software says "no connection"

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[steve]

The 1G ECU has several "modes" based on the state of some of the pins. The one your interested in is putting the ECU into diagnostic mode so the datalogger can talk to it. To do that you need to pull ECU pin 2 to ground.

I'm not sure what cable you have running from the ECU to the Keyspan USB to RS232 adapter but it will need it's ground to complete the data circuit and something will need to pull pin 2 to ground. In the car that would be the wire that ran to pin 10 on the DLC connector and it's often just a branch of the the connection to DLC pin 12 (the ground)

Without grounding pin 2 the ECU is in normal mode where it either outputs a heartbeat or a list of fault codes.
DSMLink's ECU firmware also has a mode where you can lock the ECU in ECMLink comm mode on the Misc tab and while it speeds up the time it take for the two to talk it's better to leave it off so other tools will work.

Keep in mind that DSMLink needs the power to remain on after you tell it to shutdown so it can save it's volatile data. That's normally part of running a MPI relay to power the ECU like we've discussed before.

 

[NineThrityONE]

The 1G ECU has several "modes" based on the state of some of the pins. The one your interested in is putting the ECU into diagnostic mode so the datalogger can talk to it. To do that you need to pull ECU pin 2 to ground.

I'm not sure what cable you have running from the ECU to the Keyspan USB to RS232 adapter but it will need it's ground to complete the data circuit and something will need to pull pin 2 to ground. In the car that would be the wire that ran to pin 10 on the DLC connector and it's often just a branch of the the connection to DLC pin 12 (the ground)

Without grounding pin 2 the ECU is in normal mode where it either outputs a heartbeat or a list of fault codes.
DSMLink's ECU firmware also has a mode where you can lock the ECU in ECMLink comm mode on the Misc tab and while it speeds up the time it take for the two to talk it's better to leave it off so other tools will work.

Keep in mind that DSMLink needs the power to remain on after you tell it to shutdown so it can save it's volatile data. That's normally part of running a MPI relay to power the ECU like we've discussed before.

So the unit came with a cable that had the plug to connect to the one inside the car for the obd port, I just pulled the wires (only 3) out and connected directly to the ECU

Can you clarify, perhaps rephrase "pull to ground"? I mean this only has 3 wires and one (the one sticking upwards in the pic) is clearly the ground.....where/how do I "ground" it? I mean is the -neg terminal of the battery the "ground"

 

[steve]

Ground in this case is the negative terminal, you can connect to the battery or to either pin 101 or 106, one of which may be open but it might be easier to reach the battery negative.

Pull to ground is what the transistor drivers are doing, when active they allow current to flow through them and that causes the voltage to drop. Most of the circuits on the ECU work that way as do many of the other circuits in the car, rather than switching the power side they switch the ground side "low".