EFI Connection Bench Harness

[longhornss]

Hello everyone I have a EFI connection bench harness and a windows 7 laptop. I fries my MUX chip in my interface. I am not saying that the Harness is a problem but I have decided to install a fuse inline before the control box switch. I was wonderiing if I should also add a switch to the ground wire feeding the box because as soon as I plug the harness into the wall or connect it to my batterie (I modified it to accept either a wall plug or a jumper from a batterie) the OBD port is live, adding the fuse should protect the whole harness including my ECM and ODB port(interface) the switch would act like an ignition swith that I could control better than just pliging in and un pluging. If anyone has any other thought on the subject I would appreciate it.

Also if I do not add this swithc is there any spacific order I should be connecting all my devices so I do not have this problem with the MUX chip again.

Just another note about the wiring on the original setup for the Harness. The odb and ecm have a live wire (orange) connected as soon as the harness is connected to power and when the switch is fliped it has a an ignition wire(pink)

Thanks for any advice.

[longhornss]

OK so I added the fuse and switch to the whole setup and did the read on my ECM and everything went the way it should this time. I added the switch so that I would not have to plug my ECM into a live plug or so that I would not run the risk of plugging into the wall and causing a spike with the ECM already connected.... I guess I am just really paranoid about frying the chip again, or worse my ECM.

[murphinator]

I hear you on the paranoia , I fried 2 different interfaces , one on a cheap invertor , the 2nd on a highly recommended $175 Targus 12v power supply cord. the 2nd interface replacement came in with a little caution slip of paper not to use any power source other than your laptop battery or you may fry your interface . bought a different laptop with good battery life and never try to charge it in the car while using interface and havent had an issue since

maybe you could run your benchtop on a spare car battery that you put on a charger between uses of your bench harness ???

[loppad]

Interesting because the OBD2 port in most trucks is wired to a 15A fuse which is the same for the cigarette lighter/accessory 12V plug. I know this because if this fuse is blowout the HPTuners interface won’t turn on before pluging it the USB to the computer. How many Amperes is your fuse by the way?

[PitchblackC3]

I use a 120v AC- 12v Micronta power supply for my harness I built myself. I did build a "ignition" switch into the harness. The power supply also has a fuse built into it and has a switch to turn it on/off.

Never had any problems with this setup.

[longhornss]

Interesting because the OBD2 port in most trucks is wired to a 15A fuse which is the same for the cigarette lighter/accessory 12V plug. I know this because if this fuse is blowout the HPTuners interface won’t turn on before pluging it the USB to the computer. How many Amperes is your fuse by the way?

I have built in a 15A fuse, the street a and performance engine harness I have protects the OBD2 at 20A so I just went a little smaller for safety. I have also modified my power input to accept the wall plug as well as a set of alligator clips so I can use a battery. The switch I added makes it more like an ignition so I can shut down and unplug methodically