bgbainbridge

Short question: Is there any wiring that can't be cut and extended in the engine and trans wiring harness? What are the 3or4 small gauge wires that go into the ignition switch, can they be removed? -if not how can I hook them to a simple ignition system?

Long form of the same question:
Working on putting a lq4 into an old Cadillac. I was able to drive it around the block about a month ago at the time I had only cut out some wires from the original Express3500 harness that weren't needed (example radio harness, headlights....) After the drive I decided that I would mount the PCM and fuse box.
Now the car will turn over and cough, but won't stay running, (plenty of fuel pressure)
The 2 big changes that I can thing of are, extending a 12pin plug that runs from the ECM directly to the fuse box, not sure what they were but the were all copper ~18ga wires. The other variable was I wired in the Caddy's ignition. The van had a plain cut key and with the car turning over and coughing I assume that I don't have VATS, but there were 3 small gauge wires that go into the ignition that I didn't know what to do with, could this be my issue?

thanks for your time
Brad

JoeNova

Without knowing what wires you're talking about, its hard to say.
You can cut/extend any wire in the harness that you want. They are just wires, no magic there. The engine harness shouldn't have any wires that go into the ignition switch.

ls1nova71

iTrader: (4)

Sounds like you're using the whole wiring harness out of the van? Column too? If so, the wires could be to the ignition switch could be your problem, because I'm pretty sure vans have VATS too.

G Atsma

I would bet any GM product from the last 20 years has VATS.

Old Geezer

iTrader: (3)

Spend a few $, download/print the wiring from Diyalldata.com.

bgbainbridge

Thanks for the replies, I am using the harness from the van but didn't keep the column, just the ignition switch.
I will have to try and wire back in the ignition switch.

Here is a photo of the wires I wasn't sure about

green camaro

yes those are important and you need them matched to the VATS box. or get someone to unlock pcm for you. if the vats box and key are not correct to the pcm it will only have ign, for 1-2 seconds before killing signal.

bgbainbridge

thanks again,I ran a jumper back to the ignition with it plugged into this little harness and seemed to do the trick.

I appreciate the help