Ls swapped, but no OBD2 connector?

[Jmiller022]

I just bought a 68 stepper with a 5.3/4l60 in it and it runs and drives great but there is no OBD2 port for me to hook into for tuning changes to be made from the PCM.

I asked the guy and he said he never got around to wiring one in since he was staying completely stock.

Is it a separate harness? I assumed it was part of the main harness.

If it is separate, how would one got about getting said harness and then how would it wire in?

[68GMCCustom]

sounds like you need some schematics, the pcm pins, and a connector..... curious if it has a fault indicator light?

That said...there are tuners that are set up to flash a ecm/pcm "bench style"...where you mail the whole unit to them for changes and they mail it back.

[Custom 68]

I think there are only 3 wires that go to it. Power, ground and the communications one. you may need to trace from the computer to find the right one. It is not a separate harness. my buddy grabbed the connector from a salvage yard.

[bohmankid]

easy-peasy, dude. It's 4 connections.

Pin 2. - Serial Data - FROM the PCM (should be dark green color on the blue terminal coming off Pin 58)

Pin 4 & 5 - GROUND - Usually only pin 5 is needed, however some scan tools/code readers will need GROUND on pin 4 as well.

Pin 16 - 12v+ BATTERY - Power from 12v+ Battery source.

If you don't already have the parts to wire it up, I used this link: http://lt1swap.com/fuseblock_obd2port.html

I just wired mine the other day and had it scanned for a check engine light (vacuum leak). works good.

[68GMCCustom]

are the obdII connectors pinned the same covering all years..... and all pcm's and ecm's?

[bohmankid]

Originally Posted by 68GMCCustom

are the obdII connectors pinned the same covering all years..... and all pcm's and ecm's?

Is the obdII ports all pinned the same.. yes. All OBDII ports are pinned the same through most of GM vehicles.

Are the pins on the actual PCM's the same.. I'm not for sure. They might vary with different models and years. But that info will be easy to find. Just find a schematic of your specific year/motor you have find the pin putting the wire out for your OBDII port.

My motor is a 2001 5.3 out of a silverado. The pcm has blue and red pin covers. And the OBDII port is pin 58

[clinebarger]

Originally Posted by bohmankid

Is the obdII ports all pinned the same.. yes. All OBDII ports are pinned the same through most of GM vehicles.

Gen III engines are the same, Gen IV stuff is NOT the same. The "low speed/Class 2" serial data line is on a different pin. Gen IV engines with autos use a TCM that requires "High Speed" GMLAN serial data bus lines wired to the OBDII port.

[oldvolkz]

Originally Posted by bohmankid

easy-peasy, dude. It's 4 connections.

Pin 2. - Serial Data - FROM the PCM (should be dark green color on the blue terminal coming off Pin 58)

Pin 4 & 5 - GROUND - Usually only pin 5 is needed, however some scan tools/code readers will need GROUND on pin 4 as well.

Pin 16 - 12v+ BATTERY - Power from 12v+ Battery source.

If you don't already have the parts to wire it up, I used this link: http://lt1swap.com/fuseblock_obd2port.html

I just wired mine the other day and had it scanned for a check engine light (vacuum leak). works good.

thanks brotha!
i bought a 68 with a 5.3 Voertec with out the OBD also .

[BR3W CITY]

I wanna backhand slap the people doing swaps without an COM port....for f*cks sake, even if its staying stock, you NEED access to that port. Its the primary diagnostic step for pretty much ANY troubleshooting.

...and I wanna know what kind of trash tuning they must have. No port means no tuning access. No tune access = hot garbage bench tune.

[Felino]

Originally Posted by br3w city

i wanna backhand slap the people doing swaps without an com port....for f*cks sake, even if its staying stock, you need access to that port. Its the primary diagnostic step for pretty much any troubleshooting.

...and i wanna know what kind of trash tuning they must have. No port means no tuning access. No tune access = hot garbage bench tune.

👏👏👏👏👏👏👏

[jdmurse]

Just so people are aware...companies don't always give you the (Diagnostic Link Connector (DLC or OBD II) with the rest of the harness.

I bought an LS1, 4L60E, harness and ECU from Cleveland Power and Performance (salvage yard for muscle cars) for a swap into a 1988 S10 Blazer. I did not receive the DLC with my parts.

I received:
Motor
Trans
drive shaft
accessories: starter, alternator, AC, PS pump
gas pedal, brake pedal
Harness from Fan switch to ECU including injectors, cam pos. sensor, crank sensor, O2 Sensor, gauge pod connector, etc...

Did not get:
Fuse block
DLC or (OBD II port)

I decided rather than try to make/attach a DLC; I purchased the Painless Performance LS1 harness that does include a DLC (OBD II) and fuse block. I did this because I did not want to install without the ability to tune or read codes.

I have no complaints about Cleveland Power and Performance, just letting you know what my experience was.

As far as their service goes...I bought the engine from Ebay and they packed it on a pallet and wrapped in plastic. It was immaculate for a 60K mile engine. The motor was shipped and arrived about a week after purchase.

Cheers