e30 M3 minor rust repair.

[xworks]

The actual fitting of the gauges was fairly straight forward..........



the oil pressure gauge just needing the dash hole to be slightly
massaged to allow it to fit in snug..........









the lambda gauge being even more straight forward,
just clicked into place.......







Thats it for now, more as the week goes on.

[silence]

As always... very clean.

[dogsbark26]

Yes. Nice.

Thanks for the explanations too.

[CorvallisBMW]

YES! He updated it! I'm giddy as a schoolgirl :giggle:

[Massimo]

Niceeee!

[MattAvino]

waiting for the thread to climax...

[xworks]

With all the components now in place we could move on to the next stage
of making a new engine loom to connect everything up. First step was to
disect the original loom and map it all out. Although the majority of
components being used on the new management system are different to
the standard set up, theres still a few that are original and I wanted to see how
they were originally wired up, plus a wanted to see how the bright folk at
Bmw went about powering up the loom too. The other main reason for
mapping out the original loom was to see exactly how the engine loom
connects to the body loom at the main C101 connector plug, as the new
loom would require this "interconnecter" to be used as well..........



took a fair while to draw it all out, but it was time well spent as the diagram
really helped to get my head around how the original loom was powered up.
The reason the pic below is a little out of focus is to hide the half gallon of
Tipex on the diagram..........





Once I understood how the old loom worked it was possible to move on and
draw up the blueprints for the new loom........



Next step was to obtain some fresh wiring for building the new loom,
so a quick trip to the local automotive wire specialist was in order..........



You could spent an absolute fortune buying dozen's of reels of different
colour electrical wiring from electrical wholesalers to build a loom,
or, save a fortune by dropping into the local scrapyard and pulling a
complete loom out of something fresh. It's a while back now, but as best
as I can remember I pulled the full body loom from a two year old Audi
estate car to re-use building this engine loom.........



First bit to get some fresh wiring was the injector plugs. Although the
new injectors were being wired up the same as the old ones
I wanted to avoid reusing any 20 odd year old wiring............









The upside to using mostly Bosch items for the various sensors around
the engine is they almost always use "junior power timer" plugs for
connections, which are very easy to source. Just typing "junior power timer"
in Google gives plenty of options..........







Each component around the engine gets it's plug wired up, connected,
and then the indivdual run's of wires are bunched where possible to give
the loom better strength..........





each individual run of wiring is heat shrink protected until it rejoins
the main loom body........

[xworks]

I've relocated the engine loom relays to the centre of the bulkhead
as opposed to their original home behind the coolant reservoir to
keep the wiring runs as short as possible...........



and while some of the wires coming back off the engine head
for the relays and C101 connector shown above, the majority of
them are heading back inside to the ecu.....





To help keep track on proceedings and prevent brain melt
each wire is coloured in on the diagram after it's installed........



and a little note is kept of what colour wires have been used for
what circuit to avoid using the same colour wire for two different
circuits, which should help with any fault finding many, many years
down the line, he said, optimistically.......



While the majority of wiring used came from the salvaged Audi
loom there were also a few bits that had to be bought individually
such as the screened wiring for the crankshaft sensor.........



The crank sensor sends a very sensitive signal back to the ecu
and with so many strong electrical fields around the engine
(alternator, starter, ignition coil) it's quite possible that if we were
to use just standard insulated wiring to the crank sensor this signal
could pick up a lot of interferance.
So, the solution is to use screened wiring. What you see below is
actually high grade microphone cable, and when you peel back the
outer insulation you come across a copper sheath........



under which is a layer of aluminium foil......

[xworks]

and finally, under that is the two wires we use to carry the
crankshaft signal....



The thinking behind the screened cable is any stray voltages
that are induced in the crank sensor wiring (which could cause
problematic interferance and confuse the fuck out of ecu)
will be caught by the outer copper sheath before it can infect the
main wires inside. The copper sheath is connected to earth inside
at the ecu, letting any stray voltages it has picked up pass off to earth
without doing any harm.
To add a little oil and coolant resistance to the screened wire, the full
length of cable used is covered with some resistant heat shrink..........



and because the buisness end of the cable passes reasonably close to
the exhaust manifold a little heat protection is added to prevent
barbecuing.......



One of the other things that needs a bit of thought aswell is making
each run of wire secure. A lot of wiring problems on engine looms
come from wires being loose and vibrating, leading to bad connections
or broken wires. While the wires in the loom gain a bit of strength and
security when they're all bunched and secured together, it's when they
break out of the main loom on their individual runs that potential for
future trouble can arise.

The arrow in the pic below points to one of the short studs used to bolt
a cover on to the end of the camshaft housing..........



the stud is removed and a slightly longer one installed in it's place,
being carefull not to screw it in to far where it could hit the
camshaft pulley........



once the longer stud is in place a normal flat nut can be used to
secure the cam cover in place.......



while leaving some more exposed thread too mount a P clip on
which helps secure the wiring heading to the ignition coil........



Underneath the ignition coil is another little bracket made up to
utilize the 3 front bolts from the cam housing......

[xworks]

Once it's fitted in place the crankshaft and temperature sensor
wiring now have something to be secured to as they travel across
the front of the engine........



As each sensor gets plumbed in it's not long before the loom is
starting to grow in size..........





Finally, once all the wiring is in place, the next step is to remove
the loom as a complete unit, but, before it comes out, some red tape
is used to mark where the individual branches peal off the main loom...........

[xworks]

Once thats done the loom is pulled and strung up on the wall.......



all the wiring is then seperated out while removing the ranom bits
of tape that were holding the wires together during installation
(being careful not to disturb the red bit's of marker tape)..........



and then resit them all neatly together.........



the main body of the loom can then get it's final wrapping while
using the little red bits of tape to help identify where each smaller
branch leaves the main loom ..........



The main loom body is wrapped with self amalgamating tape.
If you haven't come across it before it's basically a rubber like tape
that isn't sticky, instead when you stretch it, it sticks to itself to create
a water tight bond around whats inside.......



'tis good stuff.........

[xworks]

Next item to get wired in was the little MAP sensor we fitted earlier.....





a wee hole drilled in the plastic......



a little bit of wire, heatshrink and the correct 2 pin junior
timer plug attached........



pop the cable back through the hole in the plastic with the
aid of a rubber grommet to ensure she doesn't start to chaff
down the line..........



which allows us to move onto the next item, the C101 plug........



This is the connector located on the engine bulkhead where the
engine loom and body loom connect to each other. There's
various wires in the standard engine loom that aren't actually
needed to run the engine, such as the wiring from temperature
gauge on the dash to the sender on the engine, the feed from the
alternator warning light down to the alternator, the trip wire from
the ignition switch to bring the starter to life and a few more.
As such these wires don't need to head back to the engine ecu,
instead they split off from the engine loom up at the bulkhead and
and are wired into the engine loom side of the C101 plug.
And when the loom is installed for the final time this half of the
plug will be screwed into the Body loom side of the C101 plug to
carry the little wires on the rest of their journey..........





If you find yourself rewiring a C101 plug and are wondering what
the various part numbers for the different pins and stuff required are,
then this lad fairly nailed it in his helpful guide.........

http://www.r3vlimited.com/board/showthread.php?t=154876

With all the wires snuggly wrapped in there final resting place the loom
is roughly refitted into the engine bay and the the ecu's wires are fed
through their hole in the firewall.........



before each items wires (ecu, lambda controller, lambda & oil pressure
gauges) are dummy run and loosely secured so we can trim wires to their
final length and segregate them to individual bunches.....



once thats done the loom can come out for it's final time (thank fuck)
to have it's connector plugs attached.......

[xworks]

These little bunch of brown and black wires were the
various earths that needed to be secured to bare metal of
the chassis somewhere around the ecu. I'll freely admit to
being in the typical red blooded male catagory when it comes
to reading installation instructions, only ever read them when
the item your attempting to assemble starts to go on fire.
However, when it comes to installing Ecu and instrument earths
it's worth making the time to double check the fitting instructions.
Although all these earth wires are only returning spent voltage back
to the battery negative pole through the chassis, alot of them don't
like sharing the same ring connector to bolt them to the chassis.
And, out of jealousy, will sometimes start to fuck with each other
leading to all sorts of wierd and wonderful problems.
Most decent made products usually give some info on how to treat
the earth connections, worth reading to avoid the voodoo shit.......



Last little connector was for all the wiring traveling to the oil and
lambda gauges in the dash switch panel.......



Should the switch/heater control panel have to come out again
somewhere along the line it's a lot easier to disconnect a plug
than undo a clatter of wires.

And thats about it, engine loom was done........



Only other thing to add was the heavy gauge wire to feed the
starter and alternator which would sit along side the engine
loom when she goes back in.........

[xworks]

Once back in everything gets connected up for the final time,
including the main power feed for the whole engine loom which
I've tapped off the remote battery connection on the bulkhead........



relays and fuses get hammered home.........



Relays are, main relay that powers up pretty much everything
on the loom via the 20 amp fuse beside it, the fuel pump relay,
and the final fuse is a litte 5 amp job to protect the lambda sensor
controler from melting should it take on suicidal tendancies.....



which was the final step in building the engine loom. There was some other
wiring that needed to be addressed in the engine bay before the job could
be signed off on though. The earth straps........



Alot of the various sensors and stuff used on the engine (including
the starter) will use the engine itself as an earth path for the voltages
return route to the negative pole of the battery.
(All positive voltage wants to do is flow from the positive pole to the
negative pole of the battery, it's inherently lazy and will always take the
shortest route offered to it. Your just putting sensors and electric motors
in it's way to get some work out of it as it makes it's journey.)
As the engine and gearbox are rubber mounted, and as such insulated
from the cars metal chassis, the need arises for some earth straps attaching
the engine to the chassis and giving a route for the voltage to make it's way
back from the engine through the cars chassis to the negative pole of the
battery. As standard, the M3 came fitted with 3 engine earth straps,
the 2 pictured above and another one detailed below.
The original earth straps were starting to show their age a little, and as a poorly
connected, corroded or broken engine earth strap can cause absolute mayhem
with a cars electrical system it was decided to make up some new ones.

The first one (smaller one in the pic above) attaches from the engine bay
battery shelf to a bolt on the cover at the back of the cam box.......



The second and main one, (fat one in the top pic) attaches from the drivers
side chassis leg......



to the engine sump pan.......



and the third one is just to earth the alternaor to the engine block
(as the alternator is rubber mounted to the engine).......



And that was pretty much the end of the wiring.
There was just one or two other small jobs to complete
before we could bring the engine to life.

Will try get the next bit up for tomorrow, think I've a shite
quality vid (as usual) here somewhere of her on the rolling road as well.

Till then..........

[CorvallisBMW]

I want to have your babies.