Engine won't start with ALDL cable connected

[someguy360]

Hi Guys,

Been meaning to ask this one for a while but I keep forgetting.

I've got my ALDL port relocated into my glovebox for ease of data logging during drag runs. I can keep my windows tablet in the glovebox with TunerPro logging and not have cables everywhere which becomes a hazard if I need to get out of the car quickly etc.

However one thing I've noticed and I'm not sure if it's just the particular ALDL cable I've got, but if the ALDL cable is connected to diagnostic port, the engine won't start, it will simply crank and crank, the second I unplug the cable the engine will start.

So every time if I'm out and about data logging etc I have to unplug the whole USB cable every time I shut off the car rather than just unplugging the USB cable from the laptop/tablet I need to unplug the cable from the ALDL port and can't plug it back in again until the engines running.

Is this normal behavior, a mate of mine has a USB comms board in his VP and you can leave the USB cable connected full time without any issue. But I don't have another VR/S to test my cable on to see if the behavior is the same. If the issue isn't normal I can only imagine it's the chipset or something unique in that particular brand of cable thats causing the issue.

If anyone could let me know if this is expected behavior before I start delving into the issue further that would be great!

Thanks in advance

[Charlescrown]

From my experience you should be able to leave the cable plugged in.

[antus]

Id be checking the wiring in the port. The data part sounds like its working but it sounds like something else is wired wrongly maybe in the extension. Usually signal ground and data ground right next to each other are wired together in the interface so maybe one of those pins is wired somewhere else car side and its grounded with the interface connected and causing it.

[someguy360]

Id be checking the wiring in the port. The data part sounds like its working but it sounds like something else is wired wrongly maybe in the extension. Usually signal ground and data ground right next to each other are wired together in the interface so maybe one of those pins is wired somewhere else car side and its grounded with the interface connected and causing it.

Thanks Antus, will investigate!

[immortality]

Was it doing this before you moved the port to the glove box?

[Chr0m3]

I've always had this issue, if the command to silence bus gets sent before you start the car it won't crank (at least this is what I've experienced)

I usually just click connect as I'm cranking or after car has already started.

[pman92]

Disable VATS

[Charlescrown]

I'm a tad confused. Are you just saying when the cable only no laptop is connected to the port it won't start or is the laptop running TunerPro at the time? The cable on it own should make no dfference unless there is an issue with it.

[someguy360]

I'm a tad confused. Are you just saying when the cable only no laptop is connected to the port it won't start or is the laptop running TunerPro at the time? The cable on it own should make no dfference unless there is an issue with it.

Just physically having the cable connected to the ALDL port regardless of being connected to the laptop or not causes the car to not start, it just cranks. The second I unplug the cable from the port the car fires.

Was it doing this before you moved the port to the glove box?

Thats the thing, I honestly can't remember.....

[Charlescrown]

I tried mine yesterday and it makes no difference. It starts and runs fine with the cable plugged in.