e30 M3 minor rust repair.

[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]

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]

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]

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]

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]

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........

[MattAvino]

waiting for the thread to climax...

[Massimo]

Niceeee!

[CorvallisBMW]

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

[dogsbark26]

Yes. Nice.

Thanks for the explanations too.

[silence]

As always... very clean.

[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.

[xworks]

Which was then transferred to a piece of aluminium........



which the new ecu and lambda controller could be nailed too......





bolt her in and bingo, all the engine management components were now in place.........



But, before the wiring could begin there was another few items to get fitted,
as, although they weren't going to help run the engine their wiring was
going to be included in the engine harness.

First up is an oil pressure gauge and sensor............



Took me a while to track this baby down, but I'm glad I persevered.
It's a digital oil pressure gauge made by a crowd called Auber Instrements.

http://www.auberins.com/index.php?main_page=product_info&products_id=19

It displays the engine oil pressure in psi and has a built in relay that
allows you to wire up the low oil warning light on the dash so you
can trigger it at a pressure of your choice.
The second part is kinda handy as the standard low oil warning light
on the M3 lazily illuminates around 6 or 7 psi just in time to inform you
your engine is toast, whereas with this new gauge set up we can trigger
the low oil pressure light at around 25psi to give you a heads up
all might not be well down below in the steam room........





The second item is a beautifuly made Lambda gauge crafted
and supplied by George Graves,

http://www.s14.net/forums/showthread.php?49496-CUSTOM-GAUGES-Voltmeter-Wideband-amp-Narrowband-Last-Batch

The wide band lambda sensor shown earlier will supply a signal
to this gauge as well as into the ecu.This hopefully should help me
to keep an eye on the air/fuel ratio's and warn if the engine is
running overly rich, or more dangerously, overly lean, which will
be very handy to know especially in the early days of mapping
and running the new ecu.
The sweetest part of the gauge for me is it's all constructed inside a
standard e30 dash switch which should help keep a slightly lower
profile than some other gauges...........

[xworks]

The air flows along these tunnels and drops down into the throttle body by way of small
drillings in the roof of each individual throttle body.........



As this drilling is on the engine side of that closed throttle butterfly, the ecu now has a way
of supplying air to the engine (and hence controlling the idle) while the throttle butterflies are shut..........



As if that wasn't complicated enough theres also another bit of idle circuit pipework thats
worth mentioning. This route is the "idle control bypass" circuit and looking at the red route
in the picture below should hopefully help show where it's name comes from..........



This red pipe also feeds air up to that yellow valve between the throttle bodies, only differance
being it enters through a different port on the underside of the valve. And, as can hopefully be seen
in the pic's below, how much air that flows into the engine this route is controlled by a big brass screw..........





I've done quite a bit of searching on this whole set up and I've struggled to find much in the way
of an explanation of how it all works. So, if you can keep a secret, I've just made the following up.
With the engine running and your foot taken off the loud pedal the throttle is shut and the
engine starts to tick over. The engine of coarse still needs air coming in to allow it to tick over,
so, the majority of this air needed comes in along the red pipe, bypassing the idle control valve,
and heads straight into the engine.
The reason all the air needed to idle doesn't come in this way is because the ecu needs to
have some control over the idle speed to raise or lower it as it see's fit. So the amount of
air coming in this route is limited by that big brass screw.

The rest of the air needed for a stable idle is supplied via the green pipework. This is the air
that has to pass through the idle control valve, and, as such, the ecu can directly control how
much comes in this route. More air in, higher idle speed (cold starting), less air in,
lower idle speed (engine up to temp, doesn't need as much air/fuel to tick over).

Right gotta move on, the bullshit quota for this page has well and truely been exceeded.

Next item to get nailed in was a wideband lambda sensor...........



Shown in the pic above is the sensor itself, the wiring loom and the little red box is
the lambda sensor controller. Again this is not something thats critical to run the engine,
but it's something I'd decided early on I wanted to include in the management system.

The basic function of the lambda sensor is to send back some information to the ecu on how
rich or lean the exhaust gases are, and then having recieved this information the ecu can
adjust how much fuel is being injected. This whole circus is commonly refered to as "closed loop",
as the lambda sensor is always sending info back info and the ecu is always fine tuning the fuel going in.........



More or less every mass produced pertol engined car on the market today has a lambda sensor
hammered into the exhaust to keep the fueling perfect and the one small differance between
the sensor they use and the one I'm using above is the range they can read.
Almost every mass produced car engine nowadays run a narrow band lambda sensor.
The reason they're termed "narrow band" is these type of sensors can only read exhaust
gases that are very slightly rich or very slightly lean. They have a narrow range of measurement.
However they work just fine in their enviroment as thanks to the hundreds upon hundreds of
hours that go into programming the fuel and ignition maps in modern ecu's the exhaust gases
rarely stray to far off what they should be and hence the narrow band sensor can read
these little fluctuations just fine.

As the brand spanking new ecu I'm using is totally empty when it comes to fuel or
ignition maps then I'll be starting from a blank sheet. The air/fuel ratio's are most likely
going to be a little all over the place till we can fine tune what works best for producing the
most power. We'll also most likely end up having some areas of the rev range running rich
to produce optimum power at the expence of fuel consumption and emisions. For this reason
the wide band sensor shown above with it's greater range to read both rich and leans
mixtures is much more suitable.

The final little note about the sensor above is the little red controller box that comes with it.
Some top end, top dollar, aftermarket ecus will allow you to wire the lambda sensor
straight into the ecu and the expensive electronic wizardry inside will be able to make
sense of the small voltage signals coming in. However most ecu's will need a little controller
box like the one shown above between the sensor and the ecu to take in the small voltages
from the sensor and convert them to a nice linear 0 to 5 volt signal that the ecu can understand.

Final item to get bolted in was the Ecu itself...........



I decided that the best place for this to sit was where Bmw had decided to bolt the original ecu.........



So using the original ecu as a guide a template was made..........

[xworks]

Appoligies for the few decades that were allowed to pass since the last update.
In my defence I've plenty of excuses, a computer anti-virus program that finally scumbed
to the continous onslaught of various adult content websites resulting in a dead pc,
a broadband connection that's gone so slow it struggles to upload so much as a f**kin smiley face
and my own low I.Q. which has me struggling to come to terms with Windows 7 on this new Pc.

However,
if the truth be told,
the real reason there hasn't been an update in so long is very simple.

The car is finished.

Sorry, waited a long time to type that, so, if you'll indulge me I'd just like to do it again......

THE CAR IS FINISHED.

As I sit here typing the car sits outside in the driveway and has been back in active service now
for the last 5 months, during which time I've managed to rack up a grand total of 8560km.
Nothing major has fallen off it, there have been no explosions, I've managed to keep her between
the ditches so far, and, I've even managed to give her a few battle scars.

The plan for the build thread was always to try and write it as I went along, but,
(and apologies for this to those following the story) the plan, and pretty much everything else,
went out the window in the final push to get the car over the finish line.

So, now that things have settled down a bit and theres some free time again it's time to dig out
the last of the pictures and finish the story off.

Before the break we were trying to get all the components in place for the engine management
before the process of wiring it all up could begin. With most of this stuff fitted there was only a
few bits left to bolt into place.
First of these was the idle control valve.......



The valve pictured above is the standard M3 idle control valve. As you can see from the picture
of it's electrical connection, it's a 3 wire valve. Unfortunately the DTA S40 ecu I've choose
to use will only run a 2 wire valve, so after a long search for a suitable 2 wire valve the one
pictured below was selected as a replacement........



It's from a VR6 Volkswagen Golf and it's Bosch part number is 0280 140 512. Although the VR6
has a slightly larger displacement engine than the M3 (2800cc versus 2300cc) the idle control valve
should still work fine. The nice thing about the VR6 valve is it's inlet and outlet port sizes are very
close to that of the M3's valve, allowing the original pipework to be reused.
The new valve was mounted in the same position as the old one after making up a bracket
and using the VW's rubber mount........



Once in place the pipework could be fitted to plum the valve in...........



Before we move on to it's operation it's probably work taking a second to mention it's not 100%
necessary to run an idle control valve as most aftermarket ECU's can retain a good idle by
manipulating the fuel and ignition settings while the engine's running. But having done a little
research it certainly seems having an idle control valve may add a little more refinment to idle
control especially when the engine is being used in a day to day road car as opposed to an out
an out competition car. Some good info here

http://www.s14.net/forums/showthread.php?51396-Removing-Idle-Control-Valve&highlight=idle+control+valvehttp://

So, on to how it actually works, or more acurately, how I think it works, which as you are most
probably aware by now is, if nothing else, usually worth a laugh for how arseways I manage to grasp it.

Foot off the throttle, all throttle butterflies are practically closed blocking any air from coming
into the engine, so how the hell does the engine stay ticking over without any air coming in?
The answer is it sneaks in via the idle control valve.

In the picture below you can see the pipework attached to the ICV (idle control valve).
The big red arrow shows where the air comes in as this end of the pipe is connected to the air
box with a large supply of incoming air............



following the green arrows in the pic above, the air travels down into the ICV which to put
it very simply is just an electrically controlled tap. The ecu opens and closes this "tap" rapidly
to allow the air to progress through it. The longer the tap is open the more air that can pass
through it. You can get a picture of how rapidy this openning and closing takes place by listening
to the buzzing sound a working ICV makes. The air thats allowed to pass through the valve
continues on to the outlet pipe, which can be just about seen in the pic above.

The air travels up this pipe which passes between throttle body 1 and 2, and takes a 90 degree
turn to feed into a small valve sandwiched between the throttle bodies........



This small valve (coloured yellow below) serves two purposes. The first, which we're dealing
with here, is to route the incoming air from the ICV into the engine. The air coming up from
the ICV on the pipe we've just followed enters into the valve by the port arrowed below........



Once inside the valve it's route is fairly straight forward, the incoming air flows down into the
valve and splits up allowing it to flow out both outlet ports......



The air then flows out these outlet ports into "tunnels" cast into the top of each throttle body..........