1999 Camaro V6 to V8 Conversion

[dave w]

I'm looking for ideas to resolve a train wreck of problems created when a 1999 Camaro V6 engine was converted to V8.

What I've figured out so far:
The vehicle is a 1999 Camaro that had a V6.

The V8 conversion engine is the LT1, likely 1993. (maybe 92, both 92 / 93 LT1's use a black box computer similar to the 1227727)

The Engine Wiring is a HUGE Headache! I'm wondering if the original 1999 Camaro V6 computer is needed for ABS or the BCM?

Maybe a good plan is to configure LT1 harness for "Standalone"?

The transmission is a 4L60 (aka renamed 700R4) not a 4L60E.

dave w

[steveo]

i did help with a swap like this once, quite some time ago, but it was a 6 speed and a 1994 engine w/ $EE.. but i swear it was a 1999 car too, so we're on the same page

i seem to remember the original body modules will function correctly-ish without any input from the ECM. generally an ABS system like that will work at least in a failsafe mode on direct input from the wheel reluctors even if the engine is stone cold dead, so no worries there..

the dash can be an issue, i'm pretty sure the tach wont work in your case since your ecm doesn't even have a tach output signal, 93 cars just used coil ground (do 1999 automatic f-cars even have a tach? i forget)

i never got the fuel gauge to work but i suspected the car had a faulty fuel sender.

i did get the speedo working at least as far as being half-assed accurate, but i remember there was some screwing around we had to do, can't recall what.

of course you know this but really the wiring is only a nightmare because it's just laying there like a pile of spaghetti. there's very little interfacing truly necessary between that LT1 and the vehicle itself to get it running.

if it were me, i'd get every one of those wires and harnesses out of the engine bay right away, rip every single thing possible off the engine that you can do without, at the very least ditch the AIR system, and re-wrap the engine harness while deleting any crap you don't need.

btw it's a 1993 f-body engine for sure, can tell by the wiring and the accessory bracketry

[dave w]

Thanks Stevo for the input, it's very much appreciated.:thumbsup: Converting the LT1 harness to standalone is a good first step.

dave w

[kur4o]

I have seen 94 v6 in 98 v8 body swap. It was almost plug and play. Engine harness has 3 connectors below the glovebox compartment and 2 connectors under the hood. Most of the pins match, some need to be reconfigured.
The main obstacles were starter relay wire needs to be reconfigured. Fuel pump relay is under the hood on 99 so you have to trace where the wires go. And run a B+ wire from battery to underhood fuse box.
The dash will have two issues. The tach will output lower rpm. Unless you switch the dash from a v8 body, it can`t be fixed. The fuel gauge is driven by pcm with pwm signal. The only way to keep it running is to leave the v6 pcm connected somewhere with just the few wires needed. ground B+, ign, and the wires from tank and dash.

[dave w]

The main obstacles were starter relay wire needs to be reconfigured. Fuel pump relay is under the hood on 99 so you have to trace where the wires go. And run a B+ wire from battery to underhood fuse box.
The dash will have two issues. The tach will output lower rpm. Unless you switch the dash from a v8 body, it can`t be fixed. The fuel gauge is driven by pcm with pwm signal. The only way to keep it running is to leave the v6 pcm connected somewhere with just the few wires needed. ground B+, ign, and the wires from tank and dash.

Thanks, that is very helpful information.:thumbsup:

dave w