Lurk

iTrader: (11)

This is keeping me from starting my LS3 swap for the first time.

I'm using a GMPP harness for the LS7 (kit)

Bought a KAT-5185 MAP adapter to connect the LS3 style MAP to the LS2 style harness. (yes, the LS7 harness is based off the LS2 CTS-V)

If I unhook the MAP and cycle the power, the P0641 code clears (5 volt bus open/short)
and I get a MAP sensor low voltage signal code I think P0606

The MAP sensor is new, although any part old or new can be suspect.

I currently get no spark on either bank when cranking, barometric pressure shows correct when the engine's not cranking. Intake pressure shows a value of about half when the MAP is hooked up.

Either my MAP sensor is junk, or my Katech adapter needs to be wired different? Anyone know how I can verify either one?

Thanks! Or can anyone verify my conclusions so far? I'm gonna go search some more too.

Lurk

iTrader: (11)

Hmmmm

Katech states online that this adapter is for ls1/ls2/ls7 to ls3 MAP
I actually called in and ordered this after talking to one of the guys and asked specifically about it. but

In this thread, it appears it is incorrect....
https://ls1tech.com/forums/generatio...ls2-gto-2.html

LS2 MAP to LS3 MAP pinouts:

LS2:
Pin A - Ground (low reference)- black
Pin B - Signal to PCM - light green
Pin C - 5 volt - purple/white

LS3:
Pin 1 - 5 volts - gray
Pin 2 - Ground (low reference) - orange/black
Pin 3 - Signal to PCM - light green

<blech>

My adapter goes
A - 1
B - 3
C - 2

Lurk

iTrader: (11)

Dude!
https://ls1tech.com/forums/generatio...-body-map.html

"Caution on the Katech extention. Make sure the wires aren't crossed. Mine came with the wires incorrectly inserted to match the cars harness. Ls1 MAP should snap right in if you retained the orange grommet."

sigh hahaha

Nice to get a confirmation

Lurk

iTrader: (11)

Re-pinned my adapter and all is well. I get matching pressure from the intake to baro. and the code is gone.

rsz288

It's worth getting the ECM retuned for the different MAP. LS3's have a different calibration as they run to 1.5bar. FWIW.

Lurk

iTrader: (11)

I'll definately get that done. I tried to start this morning and get no spark still. Even ran jumper grounds straight to the heads from the battery. No spark and no code. Tried disconnecting a bank of coils. No code. Smell raw fuel and the fun shows no spark. All relays work, swapped them around plus they get hot. Appears the dbw is on the same relay and fuse, it is working when I move the pedal.

Pulled the cam sensor connector and got a code, so it seems ok.
Someone tell me the obvious something I missed

Lurk

iTrader: (11)

Gonna go read in the PCM forum and read up

rsz288

Either a wiring issue or ECM is faulty if all 3 grounds are connected.

Replaced a new but totally dead GMPP ECM yesterday on a buddy's car and also have helped a couple of ppl work through wiring errors like misterminated connectors on these harnesses so the quality is a little up and down.

Clearly your ECM is largely working but odd that injectors are operating without the coils.

Lurk

iTrader: (11)

thanksfor the input. Gives some good perspective to it.

feeling like crap today, will be hitting the packs with a voltage meter this week.

Lurk

iTrader: (11)

Self=owned

I was thinking through my troubleshooting steps last night and it occurred to me... I had tested the power on circuit for power in the key on position but not at crank. yep

Started the car just now. pregnant wife steps out to the garage with a big *** grin on her face. "that was loud!"

just that simple. I needed to make sure I had a crank/on hotwire.

Petraszewsky

iTrader: (28)

Back from the dead....I had a MAP adapter made for LS2 to LS3....No start with adapter connected...Disconnect it and it runs...Found out it was pinned wrong and repinned it...Reconnect and it starts but like 2seconds tops.....Bad sensor or sensor not compatible with my operating system??? What do you'll think???