Datalogger ECU Comm error

[4orced4door]

I've got a Palm m105 with MMCD, an ALDL/Auto On cable from ebay seller countdepolygonze (as recommended in a couple threads here), and a serial cable for the palm (it's actually a cradle with a hotsync button). The seller listed the cable I bought as being for a '91-'92 GVR4, but I am assume it's the same as '91-'94 1G? There are three pins in the diagnostic plug and no power spade.

When I try the test function in MMcD I get "ECU comm error." All the cables are plugged in tight. Car runs fine so I question whether it could be the ECU, but on the other hand it hasn't ran in a couple years.

Ideas?

 

[Brunoboy]

Happened to me cuz the datalogger cable wasn't connected tight to my palm like I thought . Check again

 

[4orced4door]

I'll try it again, but I'm pretty sure everything was tight.

 

[vtecds1]

Just wondering if your data logger logs slow. I was looking at my rpm and it is delayed alot compared to my SAFC. Sometimes it acts up also. I made a couple of logs and it showed that I went up to 7500rpm but I know I never went past 4000rpm. Any solutions?

 

[jepherz]

It can't be your ECU, unless the wiring between the diagnostic port and your ECU isn't all there. Assuming all wiring is CORRECT and in working order, the only other thing I can come up with is that you need a null modem adapter. It's been a while since I've used a palm setup, so I'm trying to remember all of the appropriate genders for the cabling...

 

[4orced4door]

I will inspect the wiring again, it's possible that there's a wire cut somewhere or something. I haven't had a chance to try the logger again.

If none of that works I'll pick up a null modem adapter off ebay for a few bucks but I don't expect it to work, considering the cable was intended to be used with a Palm. Unless of course the seller accidentally sent me a laptop cable which is always possible.

 

[vtecds1]

Quoting 4orced4door:
I've got a Palm m105 with MMCD, an ALDL/Auto On cable from ebay seller countdepolygonze (as recommended in a couple threads here), and a serial cable for the palm (it's actually a cradle with a hotsync button). The seller listed the cable I bought as being for a '91-'92 GVR4, but I am assume it's the same as '91-'94 1G? There are three pins in the diagnostic plug and no power spade.

When I try the test function in MMcD I get "ECU comm error." All the cables are plugged in tight. Car runs fine so I question whether it could be the ECU, but on the other hand it hasn't ran in a couple years.

Ideas?



Any pics? It might be the same as mine. I will take a pic as soon as i get back from picking up the kids.

 

[4orced4door]

Pics of what, the ebay cable?

 

[jepherz]

Well, being that the docking station or connection from your palm to the computer needs opposing genders to connect, there's not a huge chance that that is the problem. However, since the cables are just home-made, it's still possible. In serial ports, wires 2 and 3 are used to send/recv and 5 is used for ground. If your palm is trying to send on wire 2 and so is the car's ECU, nothing is going to happen.

Also FYI, the code within the stock ecu is in the stock eprom, so if your car is up and running (meaning the ecu is working correctly), it's not really possibly for the ecu to just not send/recv via the diagnostics port.

You can't take the cable apart, can you? I assume it's filled with glue or something.

 

I've heard that some 1990 cars have an issue where the ground in the ALDL connector isn't good enough, so the auto-ON cables don't work properly. You have to manually jumper pin #12 to pin #1 to ground it, to put the ECU in diagnostic mode. You might try it, just for the fun of it.

 

[4orced4door]

But the car's a '92, would that be worth trying?

I took some pictures of the cable. The plug was filled with glue so it's hard to tell what goes where, but you can see the orientation of the diodes through the glue, so somebody familiar with how these are made may still be able to tell if it's right. I tried to orient the pictures so that you can see how the pins are ordered too.

 

[vtecds1]

The plug in the first pic seems right...I can't don't know about the other plug.

 

[TRBODSM]

One of my buddies had the same thing going on when he bought a dsm and we found out his o2 sensor was from a non turbo. When we hooked up the logger it would say ECU Comm error and when we put a turbo o2 sensor in it and fixed the problem. I would check the o2 sensor and wiring since it will only take a couple min.

 

[4orced4door]

Interesting. I'm actually not running a factory o2 sensor at all. I have an AEM Uego wideband. The narrowband output from that is wired into the ECU with the gauge set to P4 to emulate the stock narrowband o2. The wideband is installed in the downpipe and the stock location is plugged. The car seems to run fine that way although I haven't taken it for a real drive yet.

Could that be the problem?

 

[jepherz]

Interesting, I can't come up with any reason why the o2 sensor should affect connection to the ECU via a logger; maybe the ECU gets stuck in some loop? Keydiver may know more about this.

I couldn't tell squat from your pics of the connector. That glue is just too thick!

 

[4orced4door]

I wonder if I could dissolve the epoxy somehow without messing up the wiring/connector? Probably easier just to buy a null modem adapter.

 

[Andy_S]

o2 shouldn't matter. What version of MMCD are you using? I've been hit or miss with a palm, but my laptop always works.

 

[4orced4door]

1.5d

edit - Did some searching and found 1.8g is the latest version? It's not on the sourceforge site though. I'll try updating to 1.8g and see what happens.

 

[Andy_S]

Maybe try a newer version such as 1.7 or 1.8g.

 

[jepherz]

Do you know anyone locally with a logger? That would pinpoint the issue in about 5 minutes.