pcm
 

i have a 95 z28 and i converted my lt1 to a lt4.. here are my mods so far. morso cai,pacesetter longtubes and ory,magna flow 3" out the back,lt4 intake and heads. hotcam. o2 sensor delete but needs bugs so light will go off.. air pump and smog delete, block off at the back of motor..

now this is my issuse, when got motor back in and running,worked out the kinks and try to get it tune on a dyno (mail in ok but not great) it could not link with my pcm... my year car is when they made the change from ob I to obII. ok now, i have a obI pcm with an obII connect under dash. what i think is there a bad ground somewhere that will not let it link.. i have check power source going to pcm and i have the 12v give or take.. is there so way to make a new ground to frame and tap into something to see if it a ground ??? or does anyone have any insight on why it will not link with software.. there just no comm.. back and forth??? oh my radio and seats and windows lost power also maybe they share to same comomn ground.. i have fuse bos taped for power... sorry so long but im just puzzled as of now!!!

1996 is when they went OBDII. I think Cali cars may have been OBDII in 95, but full OBDII happened in 96. When you were stock, did you have two cats or one? If you had one then you are OBDI.

First thing you want to check for is power to the cigarette lighter, as this is where the power is coming from for the diagnostic port. Next check shoebox's website for the proper pinout for your car.

HTH

Andy Schuck

ALL 1995 LT1 F-bodies were OBD-I. The only pins you need to communicate with a scanner on a 95 LT1 F-body are 5 (ground) and 9 (serial data) for most scanners. If the scanner happens to need external power, then pin 16 should have 12v on it (from the lighter fuse).

1995 CA emissions A4's (only) had dual cats, but they were still OBD-I PCM's with a 16-pin OBD-II style ALDL connector - same as all other 95's.

:thumb:

Did they still stick with the 3 O2 sensor setup? Was the y-pipe special for this? Just asking for the heck of it.

They had the same pipes as the 96-97s without the rear O2s. What 3 O2 setup are you referring to?

I was thinking that the OBDI's had three O2 sensors. One in each exhaust manifold and then one after the single cat. LOL, am I wrong? I'm kinda laughing to myself, because if I am wrong I've been thinking that for 10 years.

Just two cats.

Rich

:think::D Just two O2's? LOL, be thankful....my brain **** lasted for ten years!:lol::lol:

Yes, just two O2 sensors, one per bank.

The OBD-I F-Bodys had only 2 pre-cat sensors, and that includes the 95 CA emissions A4. There were no after-cat O2 sensors. They were added as part of OBD-II to monitor cat performance.

The 94/95 Corvette LT1's did have a third O2 sensor. The hybrid control system was referred to as OBD-1.5

ok i have 12v at cig lighter, so my issuse must be with comm. wire??? does anyone know where in the pcm harness is the wire i need to test for breaks.. i should be able to run a a contuity test con wire to make sure there no breaks rite
???

Tan wire runs to pin D30 on the PCM. D is the "blue" connector.

Shoebox has all the wiring diagrams and pinouts for a 95 on his website.