Car stalls out when connecting from RoverGauge

[Phil Coburn]

I built a cable using the instructions online and an FDTI serial-to-USB cable and a 390 ohm resistor.  When I plug it into the car (1995 Range Rover Classic, 4.2L V8) nothing happens (as expected), but when I try to connect from the RoverGauge application I hear lots of relays clicking and the car stalls out.  Once I disconnect the car will barely start unless I hold the gas pedal down a bit and then it seems to run fine.

The cable specs for what I bought are provided as "Pinout Out: Black-GND, Brown-CTS, Red-VCC(5V), Orange-PC serial TX(TTL RX), Yellow-PC serial RX(TTL TX), Green-RTS".

Since I'm assuming I'm using TTL that makes the yellow TX, the orange RX, and black is ground - just like the instructions.

Any ideas what I could be doing wrong?  

Thanks, Phil

[rgki...@gmail.com]

I had same issue, but has been a while. I think I downloaded software again and it was ok. It was holding injectors open and flooding the engine.

[Phil Coburn]

I tried downloading again, with an earlier version but I get the same problem.  The engine slows down and then stalls out.  Maybe I'll try a much earlier version and see if that does anything to help.

[Phil Coburn]

I tried version 0.7.6 and had almost the same result.  The idle went down to almost nothing and then it stalled out.

Any other suggestions?

[rgki...@gmail.com]

I wish I could recall what I did/found- have you verified correct Com port? Also seems I recall that it did something similar when I selected fuel pump buttons...I am running it on an older laptop with Windows10.
If you can wait until weekend, I will connect and see if it brings back what happened.

[rgki...@gmail.com]

I'll check cable colors also.

[Phil Coburn]

Thanks. 

I'm using an old laptop running Windows XP.  I did set/check the COM port to make sure it matched.  If I use a different COM port I get a message something like "could not connect to ECM".  I don't get any error messages from the program, it just causes the car to stall out when I click connect.

[Tommy Blanton]

Phil,

  I just got  my cable made up today, & I am having the same result as you do. I am also running it on xp. I can start it up, then click on connect, & the eng runs rough for 2 seconds then stalls, & won't restart until I click disconnect. Then it is hard to start, like it is flooded. 93 lwb
 I am using version 0.8.8 windows , I wonder if I should try a different version? I tried switching the tx/rx wires but it wouldn't communicate at all that way.

[Colin Bourassa]

A few years back, I got an email from someone with a similar problem (i.e. the engine would stumble and die after connecting). He determined that the problem, or at least part of the problem, was that the Rx line was not properly inverted. If you're absolutely certain that the Rx line is inverted and that this change is written to the FTDI EEPROM, then you might want to try running RoverGauge on a different version of Windows. There's a small chance that the behavior might be different between 64-bit and 32-bit versions of Windows XP, but I'm inclined to say that this is unlikely.

If you're still having issues with the cable you built, you might want to consider purchasing one from Mark Thompson:

http://www.pistonheads.com/classifieds/parts-and-plates/parts-and-accessories/tvr/rovergauge-14cux-diagnostic-cable/5091058

--Colin

[Phil Coburn]

OK, it's been a while, but I finally got back to looking at this today.  The issue was the RX invert as Colin suggested.  I think I must have made the change in the UI, but not hit the "program" step.  Anyway, all is good now - so time to dig in and try it out.  Thanks!