So the battery has now been moved! Quite a task in the end. Took me a few days to do it, but I was on holiday and taking things nice and leisurely! Here’s how it all went. This thread here also helped me prepare for the job: Relocating The Battery To The Cargo Area - 318ti.org forum. Sorry there aren’t so many pictures at the right points as I would like (I forget when I’m in the middle of a job), but there are a few.
First off I had to find all the right bits. Here’s the final parts list, working from the trunk forwards:
• Battery clamp and long bolt
• Battery terminal bolts
• Battery positive cable (including rubber grommet for firewall)
• Plastic trim that bolts beside spare wheel well from Coupe car – has to be from a coupe in order for the battery cover to fit.
• Battery cover – clips in to above part (replaces the ‘bin’ you get on the 4 cyl cars)
• Trim holding cable against rear wheel arch in trunk
• Plastic conduit for battery cable (through trunk bulkhead)
• Battery distribution block (in engine bay).
• Distribution block clamp, if you can find one – this is on the parts diagrams as item 23, but it can’t be selected by the dealers in the UK, so must be a US only part or something. I had to fabricate one from angle aluminium.
• Square plastic plugs (white) for the self-tapping screws - there are two square holes for these on the inner wing panel, and are to attach the above clamp to the wing. There are a load of these holding bits on around the engine compartment, so you can take a couple from wherever you find them.
• Distribution block covers.
• Cable to starter motor
• Cable to fusebox
• Cable to DME (there wasn’t one long enough from the donor car, so I had to make my own).
Other bits included a new battery – the old one won’t fit in the guides already in the trunk as it is too small, so I had to buy a brand new one for a 6 cylinder car (£116!!! :( ). But no bad thing having a bigger battery, especially if you’ve got ICE! And cable ties to neaten things up (lots!).
First thing to do was to disconnect the old battery. I found at least one door has to be open at the time, or the alarm will go off for some reason! If you have a coupe that means the glass drops and doesn’t go back up, could be a problem if you’re leaving it overnight and it rains heavily. Luckily it didn’t.
Then I removed the front driver’s seat (or passengers seat if you’re LHD!). Undid all the bolts (16mm socket) then rocked it backwards and unclipped the seatbelt pre-tensioner plug for the airbag system. If you don’t plug this back in before reconnecting the battery you will get a yellow SRS light on the dash which will need to be reset with some sort of special OBD tool (which I don’t have). Once the seat was out (it’s baaaastard heavy!), I removed the seatbelt bar, plastic trim at bottom of the door frame, trim panels below steering wheel and base of the accelerator pedal (pain in the arse – I found there is a plastic hinge that unclips on the back of the pedal base, and then it just pops out of the floor, wish I’d known that before!). The carpet could then be taken up and pushed towards the middle of the car.
Next was to locate the firewall hole for the new battery line. This is a circular plate about 2 inches in diameter that needs to be punched out of the firewall to make the hole. Located just behind the accelerator pivot. Difficult to spot at first, a torch helps. A careful whack with a big screwdriver and hammer from inside the footwell will pop it out. Do it gently or it will fall and you’ll probably never see it again! (or use some duct tape to catch it).
This left some bare metal showing. If you’ve read my other project thread you’ll know I’ve spent ages getting rid of rust, so now I’m always covering up any bare metal that gets exposed during work with the touch up pen so it doesn’t come back!!
Once that was dry I could start laying the new battery cable. The one I got from a breakers was from a E36 touring, but they are exactly the same length. I added some black insulation tape to the sections with that horrible fabric insulation tape that goes sticky when it gets old, to save getting sticky muck everywhere. I started by shoving it from the footwell through the hole into the engine bay and seating the rubber grommet properly in the firewall. This gives you an idea of where the distribution block bracket needs to go (more on that later). Then I routed it through the floor towards the rear of the car, ensuring there were no kinks or twists in it, remembering how it routed through the plastic wiring trays on the floor from when I removed it at the breakers. It goes round the side of the rear seat, in front of the seatbelt buckle mount (not behind it):
and through the rear bulkhead (the pics of the red car are actually the breaker I got the parts from, not mine):
There is also a metal plate in the rear bulkhead that needs to be punched out in the same way as the firewall plate. Dockyard spanner and FO screwdriver out again. I stuck some duct tape on it beforehand so it wouldn’t drop and get lost in the chassis somewhere and rattle around.
Touch up pen out again to cover up any bare metal. Then the plastic conduit can be placed in the hole (oor err missus). This conduit guides the battery cable through the bulkhead and stops it chafing on the sharp edges of the bulkhead. There is a green mark on the battery cable that lines up with where it goes through the bulkhead that indicates the cable is in the right position. It’s very important that the firewall and trunk bulkhead grommet/conduit tube are used and placed correctly, as the positive cable is un-fused and will cause a fire if it wears through and the copper wire touches the car body.
Next the battery cable can be guided to the battery itself. I found it easiest to install the battery in the tray at this point as this will indicate exactly where the cable needs to end up. There is also a plastic piece of trim that holds the cable tight to the rear wheelarch. The pics below show where the cable goes round the wheel arch, but with the plastic trim removed. The studs you can see below from the donor car were not present on mine, so I bonded the trim in place using five minute epoxy.
For the battery negative cable, the standard earth point stud is already located in the battery tray. So all is needed is to remove the nut and clean up the earth point with a dremel wire brush to get the contact shiny, and attach the same cable as used from the front battery location. I checked RealOEM to check the length and they are exactly the same part number. So that is the battery cable installed!
Next for the distribution block in the engine bay and engine bay wiring. In order to mount the distribution block against the inner wing, I needed to fabricate a bracket, as I couldn’t get hold of the BMW part. Lots of measuring later, I ordered a 2 x 2 x 1/16 inch piece of angle aluminium and had a go at making something similar. Below is what I came up with, turned out very well! Also leaves enough room behind it for the bonnet windscreen washer lines. Forgot to take a photo of it before I installed it:
Once the block is mounted, the cables can be installed. Looking at the donor car, these run from the distribution block, through the wiring loom tray attached to the scuttle panel and over to the other side of the engine bay to the fusebox and starter motor. It’s worth noting that I polished all of the terminals on these old cables with the dremel before fitting to clean them up, as I didn’t want problems with poor connections. To thread the cables trough the rubber conduits and tray is difficult but can be made a lot easier by greasing the cables slightly to make them go through easier. The cable for the starter motor was a pain as it’s really difficult to reach the bolt. I even considered removing the intake manifold at one point. It can just about be reached though, although you can’t actually see what you are doing, you just have to feel about with your fingers! The cable for the fusebox was easy compared to the above. There was however a cable with a ring terminal that attached to the old battery positive terminal you can see below:
I assume this is for the DME. So this needed to be connected to the distribution block as well. As there wasn’t a cable from the breakers for this, I had to find the right type of cable and make one. I was aware that it needed to be exactly the same cable or thicker. I tried everywhere to get the right gauge cable: Halfords, Maplins, 3 local motor spares shops and two electricians, all of which were a no go. I eventually found an auto electrical website and found out that it was thin sheath 84 strand 50 amp cable. Two minutes and £10 later it was ordered and arrived first thing the next day. Last time I hunt round shops for silly bits like that! I made up a new length of cable with a ring terminal and heat-shrink on one end, and crimped it at the other. Then refitted the loom tray to the scuttle and tidied everything up with convoluted tubing and cable ties. Now looks like this in the engine bay:
Having now moved the battery, the 4 gauge line for the sound system from the engine bay to the trunk was no longer needed, so that was removed, cut down to size and joined to the battery in its new place. I thought that this would cut down the length of the sound system power line (and hence resistance) quite a bit, however it was only 2 metres shorter in the end because of how it routes through the trunk. But every little bit helps I suppose! The sound system line is the extra fused line you can see below:
And here is the battery area with the cover installed:
Just before I carried this work out, the battery kept going flat after only two days. I suspected the culprit was the power capacitor for the stereo, so unplugged it. Sure enough the battery then held its charge, so the power cap is now duff. I think the dielectric inside breaks down over time and allows it to leak. Annoying as it was £40 to start with, and a pain to install! I will leave it for now though, as I now have a bigger battery anyway, and HID lights (which shouldn’t dim with bass drops as they have their own ballasts). I have also read conflicting info. on power caps on the internet, some say they work and make a difference, others say that they don’t. But I have yet to find an article arguing against the use of power caps for sound systems that isn’t written by a complete arse in a patronising, sh*tty way! If anyone has trawled through the dross and knows of a site that will just give the facts, let me know!
It was handy the glovebox had been removed to get to the old sound system cable, as I thought I'll need to recode the alarm key fob now the battery has been disconnected. But when I reconnected the battery, I found the fob still worked. However I had a spare fob that I had spilt a drink on years ago and shorted it out which I’d never got round to fixing. I cleaned it out inside and put a new battery in it, and thought I’d have a go at coding both alarm fobs. This thread helped me with this: E36 Alarm Identification Guide - 3T, 2T, 3G EWS. Mine is the later EWS II 3G system with the black box behind the glovebox and coding switch. The procedure I followed was:
• Sit in the passenger seat with both fobs to hand and both doors open.
• Removed the rubber plug.
• Flicked the switch across – the hazard lights and alarm led then flashed a few times.
• I pressed the red button on the first fob (nothing happened) and then the red button on the second fob (again nothing happened).
•Then flicked the switch back across. At this point the system armed itself and the alarm sounded. I pressed the grey button on one of the fobs to silence it, and the grey button again to disarm it.
After the above both fobs now work! Tidied up the wiring and then reinstalled the glovebox. Other work in the foot-wells I did at the same time whilst the trim was out was to remove the tweeter mounts and spray them black. Infinity speaker mounts are usually silver and it bugged me. Two coats of primer and then two of satin black and they look much better and no longer annoyingly catch your eye:
Whilst the driver’s seat was out I also installed the fire extinguisher and mounting plate that I had bought from BMW. £80 all in, but I needed an new one anyway and didn’t like the way id mounted it in the footwell. After fitting I don’t think it can be done with the seat installed so it was a good time to do it. Looks good now, tucked under the seat and out of the way: Got several jobs done at the same time over these three days!
So I refitted the carpets and driver’s seat and started up to test everything worked. Started first time. Battery reading just over 14 volts at idle so all looked fine. After refitting everything back in its place, including seatbelt mounting, carpets, door side trims, driver’s seat bolts, trunk wheel arch trim, rear seat, and tidying up the sound system cabling, a good vacuum and fully securing the battery clamps (and greasing), I took it for a test drive to double check everything was working as it should. No problems at all. The only thing I noticed was some interference through the stereo that is linked to engine speed. This was there before the battery move but is now slightly louder. It doesn’t increase in volume with the stereo, so I suspect it may be interference through the antenna. I’ll remove the head unit soon and unplug the antenna, and if that gets rid of the noise that will confirm. I don’t actually know where the antenna is on the E36, I read somewhere it uses the rear window heating element as the antenna but can anyone confirm this? I feel an aftermarket antenna will be on the cards as the Nakamichi head unit never has picked up any radio at all which is annoying when you’re on the move and bored of a cd!. I won’t be drilling holes in any bodywork though so perhaps an aftermarket window stick on type one if I can find something like that.
So all in all, a successful few days! Thanks for looking, all comments welcomed both good and bad!