I guess some more info for everyone who isn't apart of the other forums...
My car is a 92 323... It had a KLDE swap in it before... Back in july I threw #6 rod bearing during an autocross event...
I decided to update the car so I picked up a used KLG4... The KLG4 I managed to figure out came from a 2001... The wiring harness I got was from a 99 626.. I got the complete engine harness (there are 3 harnesses to it. Alt/Battery cables/starter cables ect to the fuse box. Main harness from the PCM to most of the engine sensors. A small sub harness on the back of the motor to a couple other sensors, fuse box VIRS solenoids. The main engine harness and the small sub harness have to be from the same year car... What was left of the harness that came with my 2001 motor is different then the 99 harness I picked up to use... The most obvious difference is in the O2 sensor wiring and the 2 connectors between the main harness and the small sub harness... In 99 the rear O2 sensors are part of the main harness from the PCM.. In 2001 they moved the rear O2 wiring to the small sub harness at the back of the motor...
My car was a mix mash of wiring from the previous owner, so when I did the swap I went well beyond what I needed to... I wired my car from head lights to tail lights with a stock wiring harness from my gf's old 94 Mx3 gs.. This made a lot of work for me.... Things like blower motor/hvac wiring, ignition switch, turn signals, rear defrost, hazard switch ect were all totally different and had to be a mix match of 323 and mx3 stuff.. :S I should have just gotten a complete 323 harness, it would have saved me about 15 hours of farting around making it work properly..
Even though the KLG4 is OBD2 mazda didn't really change how they powered everything up, and how the PCM controls things.... Both the KLG4 and KLDE us a main relay for power to the fuel injectors/pcm/sensors/O2 sensors... The wiring runs in completely different patterns, so you have to figure out a good way to make them match up..
Cooling fan, VSS, Fuel pump, Coolant temp gauge, Tach, Oil pressure idiot light.. All the wiring for this gets done at the connectors on the fire wall behind the stock PCM.. If you under stand circuit design, its all very straight forwards...
Fuel pump control for the KLG4.. Make sure you use the right wire, there are 2.. One would have been used if the donor car had an immobilizer, the other is with out.. I have no clue what my donor car had, so I just wired it up as though it didn't have an immobilizer...
Main power for the fuel pump relay.. You'll need to wire this in.. The KLDE gets the power threw the stock engine bay harness.. the KLG4 doesn't have any wiring in the harness for this... There is a Blue wire in the stock wiring harness that would have been used on the KLDE to supply power to your ignition coil.. This no longer gets used, so I patched into it with a fuse to supply power to my fuel pump relay and my fuel pump...
Tach.. I am still sorting this out.. It should be possible to make a tach adapter that would connect to all 3 coil control wires for the KLG4 coil pack.. You would then feed this signal to your stock tach wire under the dash... The electrical parts to do this need to handle up to 400 Volt spikes.. I think the resisters I used were to small, when I made up an adapter my tach worked for about 10 sec then stopped.. I am pretty sure I was sending to high of a voltage spike to the tach and fried it... I have found this Tach adapter online, but have no tried it...
http://www.autosportlabs.net/TachAdapter
I do believe though I have found the proper Engine speed output signal from the stock KLG4 pcm... Wiring diagrams don't list it, I only lucked out and found it on a PCM connector pin out diagram berried in Alldata.. I do believe I'll be able to build a transistor type tach adapter much like you would us if you had megasquirt to drive the tach...
When I figure it out, I will update...
VSS needs to be spliced into both the PCM wiring, and gauge cluster wiring..
Alternator wiring I just used the stock KLDE harness and modified it where I needed to...
Main relay.. You will need to run your own ground wire for it.. The ground wire is routed threw the stock KLDE engine harness... There is also a purple wire that goes to a 10 amp ST fuse in the KLDE fuse box.. This also gets wired in.. the KLG4 uses the same fuse, so just find the right wires and splice them together... Its power supply to the computer during cranking conditions..
On my car, I have changed the cooling system around... I upgraded the rad to one from a 3.1L V6 cavalier and over flow tank... I am now running a complete closed cooling system... I am not sure yet how it'll work out having the surge tank tapped into the upper rad line, but so far its been fine.. Usually the surge tanks are mounted in the lower rad hoses..
My transmission is a stock mx3 case with complete escort gear set up... This gives me a more even spread 3rd and 4th... The really nice 0.717 5th gear... I have also changed from 4.38 final drive to the escort 3.85 final drive... If my calculations are correct cruising at 70mph I should be around 2500 - 2700 rpm in 5th gear... The diff I picked up is a KAAZ clutch type LSD... Since this car is built for autocross racing I opted to stay away from Quafie and Mfactory gear style diffs due to their tendency to act like an open diff if you really unweight an inside tire during cornering....
Lots of fun pictures to post...