Does my check engine light need a ground or 12v?

[rang-a-stang]

Every diagram I see for TBIs just shows a line to the Check Engine/Service engine soon/Malfunction Indication light. I assumed the computer applied 12v to light the light. Or do I apply 12v to the light and the computer grounds it to turn it on?

[wiley-moeracing]

I believe it is ground switched. not 100% sure on yours.

[babywag]

Or do I apply 12v to the light and the computer grounds it to turn it on?

This ^

You sure you don't want to break in your new engine w/ a carb before experimenting/debugging a TBI install??

[rang-a-stang]

You sure you don't want to break in your new engine w/ a carb before experimenting/debugging a TBI install??

HAHAHA!!! I am definitely making your point for you, aren't I! LOL!

[babywag]

@ minimum should monitor data to try and make very certain it isn't too lean.
too lean and you risk chewing up cylinder(s) and/or piston(s).

what is your plan on a .bin?

[Curly5759]

PCM is the ground for the light. Back in the day, when we wanted the CEL to flash codes, we would put a jumper wire between socket A and B on the ALDL (Assembly line Diagnostic link) It's called the DLC on OBD 2 vehicles.

[rang-a-stang]

@ minimum should monitor data to try and make very certain it isn't too lean.
too lean and you risk chewing up cylinder(s) and/or piston(s).

what is your plan on a .bin?

Will do. I downloaded ProTuner this weekend and am watching videos on how to use it.

.bin: I have one computer from a stock 95 350 and also bought this setup:

http://www.ifsja.org/forums/vb/showthread.php?t=186447

He had it on his 440 which is very similar to my build: Similar cam, similar compression, headers, timing control, etc. I know I will need to tune but his .bin should be in the ball park for me and close enough to break in the cam? I am using his injector pod now (28psi, I verified it this weekend) and computer. I hope to get into that .bin this week and see what's in there. ProTuner is all new ground for me so I have a steep learning curve. Luckily there is tons of info out there, I just need to spend the time to learn it.