LawrenceF

I've been offered a second hand 1995(6?) LT1 complete with PCM, but it's nothing like the PCM i have on my current LT1. The box has this number on:



It looks like this:



Which looks like one off a TPI from the pics I can find. Im in the UK so can't go and get one from a junkyard easily!

ricknbird350

iTrader: (21)

i have one identicle from that and it should have been in a 95 t/a but it looks to me like it was outta the 93 cuz 93 had a computer chip you could put in it and there is a cover on that comp for one...i need a 94 one if you know anyone that might have one

LawrenceF

There are always a couple for sale on ebay. Is it definately a chip under the cover, not the knock module? Heres a pic of a knock module in case you've never taken one out

buffman

iTrader: (9)

that looks like a 93 Computer to me. Didn't the 94 pre LT1s have the rear fuel line crossover as pictured?

rkinney

That part # is definitly a 92 93 speed density pcm.

harvickgm

iTrader: (10)

its a speed density LT1 computer, for 92-93 LT1's only, the only difference for these is of course no MAF, (i love that last part), and there is no knock module in the 92-93 computers. the MAF and knock modules didnt start until 94. the wiring harness connectors on the back were different as well so they are not interchangable without alot of modification
SPEED DENSITY ALL THE WAY BABY

LawrenceF

Well, I now own the motor. That makes 2 LT1's for me. But now i'm confused as this has a knock sensor? Is there anything else to look out for to spot a pre-94 motor, or do I need to strip it down and look at the number stamped on the pad? Thanks for the help so far!

Alex94TAGT

LawrenceF -- the 1992-1993 LT1 will still have a knock sensor on the bottom/passenger side of the block. There's just no knock module within the computer. The photo you posted from Wing Chow's website (97ta.com) is, naturally, a 1997 PCM w/ knock module.

The engine in your first photo is, without doubt, a 1992-1993 model year. The AIR/EGR lines are different than 1994-1997, no front crossover tube on the fuel rail, fuel pressure regulator on the reverse side, the guys above already identified the computer as a speed-density model, etc..

[Edit] However, it might be interesting to pull the oil pan and check for 4-bolt main caps. Is it possible this motor came out of a 'vette?

LawrenceF

Ah, that makes sense then. Thanks Alex. It's allegedly from a Z28, but it was also supposed to be a late '94. I think I'm going to try and get a complete second hand harness from a '94 and have a go at setting it up with a MAF. I know that sounds dumb, but it's going in a '55 bel air that I'm building, so I might as well start with what I know from my other LT1.

Thanks again for the help everyone.