MPVI permanent install

[Reucroft]

My problem is that the MPVI will drain the battery if I leave it hooked up with the green light on. If I disconnect it to leave the car in the garage for a week then sods law says I touch the serial against the MPVI and the resulting spark blows the fuse in the passenger footwell.

What would be nice is an on/off switch on the MPVI so that I can just turn it off rather than having to disconnect it (with the risk of shorting).

[Casey]

Run the power wire of the OBDII port to a switched igntion source instead of battery...


There should be no sparks when you connect the USB cable. If there is, something is wrong with your install or laptop (a bad inverter?). Fix that before you ruin the MPVI, as that is not covered under warranty.

-Ken

[kgb]

Run the power wire of the OBDII port to a switched igntion source instead of battery...


There should be no sparks when you connect the USB cable. If there is, something is wrong with your install or laptop (a bad inverter?). Fix that before you ruin the MPVI, as that is not covered under warranty.

-Ken

FYI,
I blew a fuse a week ago after reconnecting the serial cable to the MPVI while the other end was connected to the OBDII port.

[Reucroft]

Thanks Ken, good idea - that's pin 16 - right?

How do I access that, just cut into the cable?

The spark/shorting issue is not when I connect the ODBII serial to the MPVI pro, it's when the ends touch but are not lined up - for instance if the screw in the serial connector (other end of the cable from the OBDII port) touch the metal surround of the serial connector of the MPVI, then it sparks. If I line them up for connection then no problem, no spark. The problem is that I leave these unconnected in the centre console and they can easily touch accidentially.

[Casey]

Yes its pin 16. Just cut the wire on that goes to the OBDII connector and route it to some fused ignition source.

Sounds like you are shorting out the power pin on the OBDII cable to something else in your car while things bounce around. Just make sure your power source is fused

I always leave the OBDII cable connected to the MPVI. Those pins are not meant for constant connect/disconnect service and will eventually wear/spread out.

-Ken

[SilverG]

I too was wondering about leaving it connected. So it is ok to leave the ODBII connected to the truck and the serial end connected to the MPVI at all times? What about leaving it in the truck in cold temps, like below freezing? I keep it away from the heater outlet so it warms up slowly.

I will move it to a switched power supply if I start to have problems with the battery.

[TiredGXP]

FYI,
I blew a fuse a week ago after reconnecting the serial cable to the MPVI while the other end was connected to the OBDII port.

I've blown three, now. Finally learned to disconnect the other end of the cable from the ODB port first.

[umrjmac]

Resurrecting an oooooooold post, but making a semi-permanent installation is something that I want to do.

Rather than re-wire the ODBII port on the car, I was going to create a little 2" cable with M/F DSUB15 connectors between the DSUB15 end of the ODBII cable and the MPVI Pro box. I am going to use a DMM to figure out which pin on the connector is connected to pin16 (unswitched power) on the ODBII port and then insulate it and not pass it through, then use a switched power wire for that pin on the end facing the MPVI Pro unit.

Since the MPVI Pro box will be within a few inches of my NGK AFX control box (mounted in the glove box), and since I already have a switched power wire ran to that from an open fuse spot in the fuse box at the bottom of the passenger firewall, I would like to use the same wire for this. I can also tie the ODBII chassis ground (and signal ground?), and the EIO ground into the ground wire that I have run for the NGK box, so everything is using a common ground.

Long story, I know, but I have a few questions. First, is there anything wrong with doing this?

Second, how much power does the MPVI Pro box pull? I want to be able to fuse this appropriately. The NGK AFX box pulls about 3A max, so I currently have a 5A fuse in that spot.

Is there a wiring diagram for the DSub15 side of that cable posted online somewhere? I checked through the help and searched the forum, but didn't find anything.

I am curious which pins are actually in use and which aren't. I see 5 "discretionary" pins on the ODBII side, but do not know which ones GM makes use of. Maybe I could get creative and put the EIO port that I use into the mix to make a quick disconnect of some sort that way I don't have to unplug the green plug when I take the box inside to pull driving logs.

It looks like "another" tuning product uses a total of 8 wires for their interface:

1 12 V
2 CAN High
3 CAN Low
4 Ground
5 CAN (Low-speed)
6 VPW
7 ALDL
8 Ground

Since the ODBII pinout looks like:

1 GM CAN (Low-speed, Single-wire)
2 SAE J1850-VPW Positive
3 Discretionary *
4 Chassis Ground
5 Signal Ground
6 ISO 15765-4 CAN High
7 ISO 9141-2 & ISO 14230-4 K-Line
8 Discretionary *
9 GM ALDL (OBD-I 8192bps)
10 SAE J1850-VPW Negative
11 Discretionary *
12 Discretionary *
13 Discretionary *
14 ISO 15765-4 CAN Low
15 ISO 9141-2 & ISO 14230-4 L-Line
16 Unswitched Battery Power

Then that product is for sure not using ODBII pins 3, 7, 8, 11, 12, 13, and 15...is it safe to assume that HPTuners isn't using those as well? If so, then a quick disconnect should be easy to rig up

from: http://download.efilive.com/Tutorial...20Tutorial.pdf (citing my source for the pin-out info)

[Klubba]

only 4 wires needed:

http://www.team3rdgen.com/modules/3r...ter_tuning.htm

[umrjmac]

Thanks for the link

Does anybody have any insight on the other questions?

[umrjmac]

I spent a little quality time with my DMM and the HPTuners cable. I couldnt find a pin-out diagram anywhere, so I figured that I would go ahead and post this up to save someone else some time.

ODBII   HD15   Notes
  1       9
  2       1    SAE J1850-VPW+ (Serial Data)
  3       3
  4      13    Chassis Ground
  5    Shield  Signal Ground
  6      11    ISO 15765-4 CAN High
  7       6
  8       8
  9      14
 10       2
 11       4
 12      15
 13       5
 14      12    ISO 15765-4 CAN Low
 15       7
 16      10    Unswitched Battery Power

Assuming that the ODBII pin usage is consistent between this and the "other tuning app", I have listed out in the "Notes" section what the relevant pins are.

The older (Gen3 V8 style) stuff just needs pins 2, 4, 5, and 16 (data, ground, ground, and power, respectively).

The newer (Gen4 V8 style) stuff also needs the CAN High and Low pins.

(Pardon the code block...i couldnt figure out another way to make table-style data within the bulletin board)

[wstaab]

I spent a little quality time with my DMM and the HPTuners cable. I couldnt find a pin-out diagram anywhere, so I figured that I would go ahead and post this up to save someone else some time.

Have you verified your pin out diagram is correct for the HPTuners MPVI interface?
HPTuners support will not supply the pin out configuration for their DB15M (VGA style)connector.
I need to fabricate some right angle OBDII connectors to eliminate the entanglement from a cable hanging between your legs while driving.

[umrjmac]

Have you verified your pin out diagram is correct for the HPTuners MPVI interface?
HPTuners support will not supply the pin out configuration for their DB15M (VGA style)connector.
I need to fabricate some right angle OBDII connectors to eliminate the entanglement from a cable hanging between your legs while driving.

I checked it twice, but if I were you, I would just take a DMM with the supplied cable and run a continuity test to doublecheck my work. If you run into any discrepancies, post up here and I'll verify them and update the image, if need be.

Thanks

[260B4U]

HPTuners support will not supply the pin out configuration for their DB15M (VGA style)connector.
I need to fabricate some right angle OBDII connectors to eliminate the entanglement from a cable hanging between your legs while driving.[/QUOTE]

its just a cable whats the big deal why wont they offer a pin out
i too would like move my obdII port to the pass side via a 90deg thin connector or removing and un pinning and re pinning the connector after its been extended so i dont break it while driving

[Phantom]

Or the easiest thing to do instead of building a connector is to get an obdII extension or splitter. Then remove the obdII port mount and place it above the kick panel use the splitter to direct it over to the center console area and then use it.