Shortly, I'll be fitting a replacement engine wiring harness, and looking for some tips and tricks for doing the job. Currently dash is out, however all the AC gear is still installed. Interested to hear advice from those who have installed their 'wiring specialties' or replacement OEM looms in the past.
On the Silvia all I had to do was unplug the ECU harness, the body harness and feed it through the engine bay then just unplug everything else. You shouldnt need to take the dash out. Well, never done it to a Z but I cant see it being much different to the Sil.
Massive pain. Does you aircon need re gas? If it does take out the box thing under the dash. Way easy. If not, undo the seal on the firewall where the air con hoses go in. Undo the box from under the dash. You need to kinda pull the box back and down. The reach over the top and undo the 2x 10 mm nuts and the you can pull the loom out thru the engine bay. Be warned it's a huge pain to get those 10 mm nuts off
Aircon, to the best of my knowledge is gassed however the pump is seized. Without a set of gauges I wouldn't know I guess. I really dont want to degass it if I can help it though. I've got enough ratchet spanners, sockets and everything else to get the nuts off, so I'll give it a crack. I guess it'd be 10x easier again if the windscreen was out, but also not an option. Cheers for the tips.
I did a replacement loom without moving the AC box. Very annoying and time consuming and if you leave the AC box in place you won't be able to secure the loom with the factory cable tie that comes with it. No biggie as the loom doesn't move at all in the confined space it is in...
What's the use of gas and no pump? To replace the pump you loose the gas anyway. Might as well get rid of the gas now. Make replacing the loom easy and empty the crap that builds up in that black air con box
You can always give the ac valve a quick press to see if there's gas in there (like a tyre valve) just don't breathe the stuff lol.
More worried about the massive fines associated with releasing a refrigerant. Normally a fridgey will evacuate it and reclaim the gas. Not really an at home job.
Give one a quick call, see if they will come out and do it for free if they get to keep the gas? Only loss to you is a phone call.
Use ryzan's trick to check before you go to any hassle, valve is under a little red cap on passengers side, easily accessible. Also it might be worth looking up the regs if you don't mind losing the gas, I've heard its not illegal if you aren't a licensed fridgey.
I was just saying to do that to test if there's any gas actually in the system, don't do it to vent the lot if there is.
I replaced my engine wiring harness last year with a brand new one from Wiring Specialties. All i did was, after i removed the old harness i layed the new one on top of the engine and started off plugging in the injectors first. The Wiring Specialties harness comes with a diagram to show which injector and coil plugs go where. After the injectors i did the coils. After that I ran the harness down the passenger side of the engine towards the relay box and the rest of the plugs literally fell into place. There was only one or two i had to figure out which was which. I must add though, i have done all the emissions deletes and have no aircon at all so in one respect the extra ososlete plugs made it a little tricky to figure out what plugs weren't being used but, the no aircon made it easier to fit through the firewall to the ecu.
Heater core and wiring loom replacment - steps and hints So just a follow up on my wiring loom replacment for those playing along at home. The final outcome Replaced my loom with a second hand, near-new Nissan LHD loom, no major differences were noted, other than a bit more slack in the loom near the battery. Overall time taken to replace loom was about 3 weeks of 'casual' work, few hours on a weekend, and an hour or so of an afternoon before it got dark while sipping a beer. I was admittedly working in a carport with poor lighting, with torch light, on a job I'd never done before. If you are proficient at removing a dash, you will do it way quicker than I did. Total time to budget - approx 6hrs to remove / refit dash, bank on about an hour to remove the old loom and all associated clips, and another 2 to get the new loom in. The replacement loom solved the issue I was experiencing where I was killing S2 PTU's after approx 50km light road use. It was also a great way to get new wiring and connectors in the car, as the old wiring was brittle and most connectors damaged. Hints for young players (in no particular order, covering work for the job Remove radio first, then work back to the centre console and gear shifter. Remove radio surround, radio, and side panels along the centre console. Remove trim cover under the drivers side (near your knees). Move the the dash cluster. Remove cluster lid (screws under visor) and then work on getting the dash cluster out. Remove side pods (screw underneath) remove face of pod and then work on the screws inside to remove pod. Remove steering wheel. Pop off horn pad, then use a 19mm (iirc) socket to remove lug. Give it a few stout whacks from the front to loosen it, then pull towards you. Remove steering wheel surround. There is some screws underneath. Then remove indicator stalk. Save all the fiddly little screws. Remove ECU (ensure battery disconnected) and begin to remove glove box. Remove side AC ducts to the door vents. Remove dash demister vents. These need to be popped off with a screwdriver. Most likely will be brittle, so expect breakages. Do similar for the side window demister vents near the A pillar. Undo the phillips head screws which secure the top of the dash near the windscreen. Look thru the windscreen to locate. Undo misc screws as seen. Put all screws and fasteners back where you found them, if possible. Sometimes I paint them with a bit of yellow paint marker to make them visible when I find them. Otherwise they just blend in with everything else. Should be ready to remove dash and assess the carnage underneath. Find a mate to help. Once dash removed, remove cross bar behind dash. Remove all AC ducting. Start with the demister vent, then work your way down, then to the outside of the car. They are mostly press fit with a supporting screw somewhere. Beware of the temp sensors in them (white plugs). Remove Blower motor. with the cross bar removed, this is easy. Unscrew top fastener, then bottom mounting points to the metal bar which supports the blower and AC box. Don't bother removing the metal clips which hold the blower motor to the fan assy. I did, and broke most of them. Not really necessary IMO. Undo AC box bottom mounts. *Gently* move AC box back from firewall. Chances are it's old, brittle and full of refrigerant. You should be able to locate the metal plate which holds the wiring loom to the firewall. IIRC, 2x 12mm nuts. In removed them with a socket, attacked from the top. Some recommend that you don't need this plate when reinstalling. I would reinstall this if possible, as it's one of the few mechanisms to stop the loom wearing thru on the firewall. The grommet on the engine side doesn't really do much to prevent movement of the loom. This should be sufficient to remove the loom from the vehicle. Feed the ECU end out the firewall. Get a mate to pull the loom while you feed it up and thru the hole. If the loom is to be scrapped, just cut it off near the firewall on engine side, and pull thru on the cabin side. Feed new loom thru the firewall to the ECU. One person pulling and guiding the loom from the cabin, the other feeding thru on the engine side. Once hooked up replace holding plate, and reinstall dash in a similar order as above. I replaced heater core at the same time. Disregard following steps if this does not apply. Remove clutch pedal at the firewall. Remove split pin and then undo the 4x 14mm nuts using a socket and long extension. Get access to, and remove the climate control computer. Remove associated connectors. If not done already, remove heater hoses at the engine side of the firewall. Also remove securing fastener where the heater hoses pass thru the firewall. Remove heater box, straight out the front of the dash. This basically slides straight forward (with a bit of wiggling to get it free of the press fit into the AC box). Clean box and piping with soapy water (will likely be stained with coolant). Remove any associated springs and levers on the heater core, and slide out. there is a few 8mm? bolts holding it in. I'd highly recommend changing heater core AND heater tap at the same time. Not worth doing half the job. Refit heater core, retighten bolt to secure pipes to firewall, and refit heater hoses on engine side. Refit dash as previous steps. Well worth doing, I did have problems with a cracked demister vent, and I did some running repairs on the dash itself (whcih was cracked). I attempted to plastic weld it with a soldering iron, but the dash plastic goes brittle with heat, and I ended up roughing it up and coating the cracks with epoxy. I took the time to clean up behind the dash. Many years of what looked like pet hair, grease and dust built up behind there. Hope this helps anyone who has searched for wiring loom replacement, or offers some tips on heater core replacement.
