2000 K3500 411 swap, additional wires found, can't perform CASE relearn

[rklumpper]

2000 K3500 L31/4L80, i swapped the computer this past weekend, and it's currently not driveable. Any pointers would be GREATLY appreicated.

Extra wires that were in the truck from the factory are present in C1 Pin 18, Purple/white wire and C4 Pin 12 Black wire. I've been spending some time on Chilton's libraries and haven't found anything yet as to what they may be.

Error codes present are
1336 - ckp not learned, no surprise
0341 - cmp sensor performance, ???? (not present before swap)
1345 - ckp->cmp sensor correlation, not surprised, but it was set back at -1.0 degrees before the computer was swapped, it ran and drove fine. I'm borrowing a good multi meter tomorrow and trying to find where these wires run.

Only error codes before the swap were for EGR low flow. This makes sense because it's currently blocked off :grin:

engine runs rough and mis-fires above an idle. Also, GMCMPRET fluctuates widely with any engine speed at or over 1k rpm. Anywhere from -44 to -115(ish). Distributor is not loose. Possible noise on the CMP signal line? Lack of ground reference or bad connection on ground reference???

Grounded pins 32 and 34 on C1, ECU thinks it's in Park, parking brake on, foot on brake, engine to temp, no status changes or counters in the scan tool or change in the way the truck runs. Misses, sputters, spits, and the CMPRET fluctates anywhere above 1k.

Possibility the dizzy is so far off that it's jumping terminals, causing the fluctation in CMPRET and bad running???


Thoughts?

Thanks!

Ryan

[rklumpper]

I also should note, the fuel gauge is pinned to the full side. I did not do any swaps to the cal for the fuel system, but the truck was at ~2/3 tank.

[joecar]

Ryan,

Welcome to the forum :cheers:

Are you sure that the CKP wires aren't swapped.
Are you sure that the CMP wires aren't swapped.

[rklumpper]

Sure enough, one of the CMP wires was pop'd wrong by myself. Case learn -> dun!

I've also lost track of the fuel level sensor signal, so it's digging time this weekend. I had marked that I moved it correctly, but the gauge is pegged... The reference line wasn't present by my recollection, and the notes are in the vehicle for what I found. I am a bit confused on the pinout of the 411, as C2 - 38 and C2 - 54 are both marked as Fuel Level Sensor Signal....????? Tank A and tank B? Maybe i have a pur/wht at c2-54 from the proper location, but nothing at c2 38 and unless i missed again (highly possible!) i don't have an unaccounted ppl wire...?

Now, from my Trans Output speed signal, i'm getting some bad info. no motion/sensing until ~15mph ground speed. Speedo is all over the place, sometimes it will drop 5-10mph when driving 35. Always reads low speed, never high. Signal does get dropped on occasion until moving ~40 mph. Bad sensor? Wiring is populated correct in the ECU connectors, I checked and checked and checked again after I checked it.

I have a connector to be identified on the firewall that has 4 wires running from the ECM and only two running out of the other side. I am going to try and identify it this weekend.

Still no luck identifying this C1 18 and c4 12 from the original harness...

Any ideas?

Ryan