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1G Can’t connect to DSMLink

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1dohc6

10+ Year Contributor
67
5
Sep 14, 2010
Greeley, Colorado
Having issues connecting to link it’s intermittent pulled the ecu what are these resistors for and it it normal for them to look like that. Let me know if anyone has a solid 90 1g harness thanks.

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I'd like to see how the board looks around the 3 capacitors that tend to leak. It looks like ECMTuning did work to this board so I'd they probably took care of cap leakage. I'm working on a board that had cap leakage much worse than this. So far I think I've fixed 7 traces due to corrosion.

Not sure your desire or skill level, but there's some things you could do to test. See if you can gently scrape the residue (corrosion?) away. Then use an ohm meter from the resister lead to the next solder connection down the trace to make sure you get zero ohms (full continuity). If you get some resistance (more than zero ohms), you have a broken trace that needs fixed.

Here's a diagram for you. Put your ohm meter leads where the red dots are to test the trace where I drew the red lines. At least two traces here to test but I'd check a few more in the general area too.
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In this pic below, I would try to test these two traces where I drew red lines but you will have to visually see where they go and where you can get an ohm meter reading, either at a "via" (where the trace passes through the board) or the next soldered component. The red circle in the upper right looks a little suspicious too.
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I'd like to see how the board looks around the 3 capacitors that tend to leak. It looks like ECMTuning did work to this board so I'd they probably took care of cap leakage. I'm working on a board that had cap leakage much worse than this. So far I think I've fixed 7 traces due to corrosion.

Not sure your desire or skill level, but there's some things you could do to test. See if you can gently scrape the residue (corrosion?) away. Then use an ohm meter from the resister lead to the next solder connection down the trace to make sure you get zero ohms (full continuity). If you get some resistance (more than zero ohms), you have a broken trace that needs fixed.

Here's a diagram for you. Put your ohm meter leads where the red dots are to test the trace where I drew the red lines. At least two traces here to test but I'd check a few more in the general area too.
You must be logged in to view this image or video.


In this pic below, I would try to test these two traces where I drew red lines but you will have to visually see where they go and where you can get an ohm meter reading, either at a "via" (where the trace passes through the board) or the next soldered component. The red circle in the upper right looks a little suspicious too.
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How do you recommend cleaning the residue/ corrosion? I’ll upload more pictures when I get off work thank you
 
I'm by no means an expert, but I used 91% isopropyl and a soft brush then a blast of compressed air. I'll gently use a plastic soldering aid (just a small plastic pin/point) to remove excess debris.
 
Stuff came up and had to take a break from the DSM. Back at it again.

I replaced the entire engine bay harness since the ECU connectors have been molested by previous owners but that didn’t fix the connection issue.

I did notice the MPI relay was turning on and off on its own so I swapped it out with a known good one. Now I can connect here and there and when I can’t connect, if I unplug the larger ECU connector (24 pin) and reconnect, all of a sudden I can connect to link.

What do you guys think could cause this ECU? MPI wiring?
 
The large connector is the one containing the ECU power and Ground pins so that's rebooting it.
Is the MPI relay still turning off and on?

There was nothing wrong with the resistors in the pictures, that just buildup of the conformal coating. It looks like the ECU has had the caps changed but I can't tell if that's a DSMLink V2 board for a 1G or a EPROM conversion board. How about a picture of the whole ECU board?
 
Thanks that answered the question about what the board was. It's a EPROM conversion with DSMLink V3 installed. There is some discoloration to the area to C37 that would lead me to replacing it and exploring the traces under the heatsink/board stiffener but I don't see a clear cause in the pictures.

Sounds like you have made some progress by replacing the harness and MPI relay. But those are pretty major changes and can introduce new behaviour. When it doesn't connect do you remember if the CEL turns on and if so what happens to it and the boost gauge?

Have you tried wiggling the connector rather than unplugging it?
 
Check engine light comes on and turns off I believe boost gauge just rises to 0. So I noticed something strange when I just have the key in the in position I can’t connect but if I turn the car on it will connect while engine is running what would cause this to happen I’ve already sent the ECU out to ecmlink and the sent it back they didn’t find anything wrong with it.
 
When key is in the on position I can’t connect my laptop to ECU but as soon as I turn the ignition all the way over and start the car the ECU starts to connect while running it will connect.
I got that, but what wasn't clear is if the ECU turns on (CEL Light, Boost Gauge moves) when you first turn the key to the ON/RUN position or until you turn it to START (all the way).

What happens if you get DSMLink to connect but don't actually start the car by stopping it from cranking before it fires off? Can you do that and get a log with it just sitting like that?

In some ways this is sounding more like an ignition switch issue than an ECU issue but clarity is critical to diagnosing unseen problems.
 
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