Serial cable wiring

[McMark]

I'm getting my third microsquirt engine running and I'm having some confusing issues with the serial connection.

I'll start with the issue - with the laptop connected I get sync issues and the comm link drops periodically. I tried two Windows laptops and four different USB adapters. All had the same issue. I tried my Mac laptop yesterday and it did the same thing but it would reconnect itself rather quickly. So I was able to tune the engine some.

I thought maybe I was getting some EMI in the harness, so I used some shielded two wire cable (ground is the shield, tx is one wire, rx is the other), but that didn't seem to help.

The other thing is that I haven't had an issue with my other setups (on other people cars with their laptops). They all have the same wiring harness design and construction. So I'm not sure what the difference is.

Btw, I'm currently using the DIYAutoTune USB adapter.

Thoughts?

[grippo]

What code versions are you using on the two installs that work and what code version on this one that does have comm problems ?

[McMark]

3.78 on the two that work. 3.83 on the new one.

[grippo]

I am just this night seeing a problem like you have, but it is only showing up when I set alphaN mode in conjunction with the new serial changes made in 3.80 and on. You aren't by chance using AlphaN mode are you ? It is set under the Fuel Setup Menu, Injector Control Menu. There is a Control Algorithm entry that defaults to Speed Density. But if it is changed to either of the tweo AlphaN entries it gives a comm problem in TS. This is a really bizarre problem because serial just shovels data, it doesn't care about what the data is. I will work on solving this problem, but can't say when I will find the cause.

[McMark]

Hmmm, no just Speed Density.

[grippo]

Ok I found a problem that has been in v3.8x code that can cause loss of comms with TS. But it only happens before wheel synch, never after the engine is running. I don't know if it will help your case, but I think i'ts worth a try. The revised code is attached. Everything should run the same as the 3.830 code you have now with no need to change your msq or ini file.