Wiring Issue In My 88 Conversion

[weazel]

Ok guys, I'm kinda stumped on this. Yesterday I hooked up just about every connector I could find from the wiring harness. The bcm, ECM, tcm, and ficm are all connected. Also the gauge cluster is plugged in. When the key is turned on, the needles act like they want to sweep, but they don't. I have a battery light, and the yellow light under the fuel gauge will come on, but turn off. Checked every fuse I could find, all good.

After all this, I thought why not hook up my v2 to see what codes it's throwing, and maybe get me pointed in the right direction. Keep in mind, At this point in time, I'm only wanting to fire up the engine to make sure it doesn't knock, or run out of the ordinary, as I have someone wanting to buy this truck.

As soon as I hook the rj45 connector to the bottom of the v2, the dang thing started smoking! So now I've got a smoked cable, and hoping not a smoked tuner...

Did some research and found that pin 4&5 in the obd port are grounds, and 16 is 12v. Saw that pin 2 is supposed to be the serial pin, but it has 12v at it as well..

Can you guys give me any directions as to where to go from here? Like I said, I'm just wanting to fire up the engine to make sure it runs and isn't a junk motor.

 

[weazel]

Forgot to add, the engine is an 03 lb7, wiring harness, tcm, bcm, steering column, and gauge cluster came from an 04.5.

 

[weazel]

Bump......

 

[duratothemax]

Well somewhere in the wiring you have a Class 2 data wire shorted to battery +.

As to where to start looking???? Absolutely no idea. You have an entire truck wiring harness ghetto-rigged and spread all over a workshop floor...the problem could literally be anywhere.

 

[weazel]

Ok, to get it "un-ghettoed" would it be best to find an lb7 truck harness? Will I need a bcm from said truck?

 

[duratothemax]

All the electronics are vin specific even if you find your wiring issue your going to need the bcm pcm tcm steering column all to "know" each other.

That is totally incorrect.

Who told you that you need an entire donor truck to make a Duramax standalone?

 

[THEFERMANATOR]

That is totally incorrect.

Who told you that you need an entire donor truck to make a Duramax standalone?

What he said, my BURB thinks the ECM is from the donor, the TCM has no VIN in it, and the BCM was flashed to an 02 work truck VIN to try and take care of most of the codes it kept throwing. You just have to take your time when building your harness, and double check yourslef on what goes where. It does help though knowing you have an actual running combo though before you go making it standalone. It would suck to go and modify something that didn't work to begin with, and chase something thinking it was something you did, when in reality the problem was there before you touched it.

 

[duramaxdiesel]

I'd just get a harness from Ben. He has all that shit sorted out already. You'll me miles ahead!


Nick

 

[weazel]

I decided before going standalone, I'd try some more troubleshooting. Found the nsbu was causing the engine to try to start when the key would come out of the lock position. So now it starts in the start position.

Going to check voltage to the obd2 port to see if by chance that was the issue to begin with.

 

[weazel]

After a lot of off and on troubleshooting, I finally decided to ditch the new dash idea and go stand alone.

Did a lot of research and question asking and figured out how to make a makeshift standalone wiring harness. Attempted to fire up the engine, no go. So it was off to more wire tracing, troubleshooting, and question asking.

Finally figured out that there was an issue with my ECM. Whether it was like that when I bought it, or if when I fried the tuner, it may have back fed and jacked something up inside, it didn't want to work. Luckily a friend of mine had a spare he is letting me borrow.

Attempted to start, no go, but it would roar up for a second then die. Went through the security bypass procedure, and bam she started right up! Idled smooth, very responsive to the pedal.

So now its off to pulling all that cable back out, and reinstalling the original dash lol. Then off to wiring up my good harness for stand alone. Seeing it fire up and not be a junk engine gave me a good motivational push to get this thing going, so now off to throwing money at it lol