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Megasquirt V8 Wiring - A detailed "How to" Guide


Hybrid_From_Hell

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Hi All,

back in the distant past - ie in 2004 ! I personally ventured into the world of Megasquirt on my Old Eales 4.5 V8.

That was the start of much learning and I did a thread all about the priocess as I learnt - being the 1st time I had ever done it,

which was this one : http://forums.lr4x4.com/index.php?showtopic=15317&page=2

Well, much has past and much has developed since then !.

As many here will know I gave up my proper job....and after being nagged started a small company doing Megasquirt and Diffs, and frankly I love it !

But, the recent "Bonfire" on the 90 V8 has done a lot of damage where the electrics have shorted, the ENTIRE ECU and Loom are toast, along with dah wiring deep inside,

So, I am going to have to build a complete new megasquirt V8 Loom....(Bugger :( )

However, I am going to do this using one of my current "Wiring loom Kits" AND I have some extar bits and bobs I will be doing /using so I have as good a install as I can get on the 5.2

It is gouing to be a VERY heavy Picture based thread, and may serve to help many in the future take the plunge and squirt their V8, without doubt wiring looms are the one area that

scares most peeps from doing this conversion, so this is to prove even a leccy idiot like me can do it, and really a HUGE step by step guide, which once done here I will be nicking chunks to improve the existing Megasquirt V8 Build cd :P:rofl::P

So, here we go, expect this to be in chunks, I haven't a time frame but I will do it as and when...I will also keep count of the "Hours" taken. pretty much this will be done on my own, so if you have mates to help the "Hours" taken WILL Drop

So, off we go :

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  • 2 weeks later...

Right

the FIRST thing to do is to decide what is going where, some things are "Pre decided" others are things you need to consider

The reason for this is simple.

If for example you are unsure where the ECU is going to go, then how can yopu lay wires to it ?

So...the things to do first are :

Fit the Trigger wheel, set up corerectly (see video on website)

Fit the VR sensor (this then gives you an "Idea" where the 2 wires to the unit go, and maybe how to get there ...

Fit the coil Pack bracket

Fit the PWM control unit and bracket if your having them

Fit MAT sensor Mounting

Fit the EDIS Module (not the Plug)

Fit or decide where the ECU is going.

Things that are fixed are the Injectors, CTS sensor etc

Mine, beingh a 90 I have decided to use the opportunity to move things a bit

Heres a few Pics.

My ECU will be going up on the 90s centre bulkhead in a waterproof box, behind passemger seat

post-22-0-98538300-1443105257_thumb.jpg

My Edis - on the front of the centre cubby box unit (yes these are waterproof, but why not have it inboard in a safe place )

post-22-0-52040900-1443105325_thumb.jpg

Coil Packs - well these are already there ! But being the 5.2 these are custome ones I had to make. But I can see where the wires need to go for the coils

the leads are I think OK, so thats something done !

post-22-0-71032000-1443105386_thumb.jpg

VR Sensor and crank wheel already are on, but again you can then get an idea of what has to go where, and how maybe to get it there neatly

post-22-0-42095700-1443105442_thumb.jpg

So, you have all the bits bolted into place, and the injectors easy to get to :

post-22-0-77399800-1443105482_thumb.jpg post-22-0-55314000-1443105494_thumb.jpg

As you are going to be working over the top iof the engine, BLOCK OFF entry to the trumpets NOW :rofl::D

So, if you are using one of my kits, everything you need comes in the box.....

Opening it is a bit tardisy, there is a lot in there....

post-22-0-41285800-1443105587_thumb.jpg

Now, its looks horrendous, but do not panick !

Each wire is seperate

Each Wire is labelled with its colour

Each wire is the colour on the wiring chart,

so, where to start ?

Again, its a process of small little projects, there are A LOT of wires to worry about, but I always start by making up the injectors loom, this will use up in one easy process 16 - yes SIXTEEN wires,

and give you the basis of the start of the new loom. The trick here is to not try to do perfection in one hit, no pins or plugs are going to be connected, we are just going to build up some wires.

I have the added luxury of having a standard 3.9 injector base handy, it also makes the process clearer, but it can be done on the engine - I chose not to

Injectors and CTS showing

post-22-0-41285800-1443105587_thumb.jpg post-22-0-38004000-1443105770_thumb.jpg

Now, the Rover V8 "Batch Fires" that simply means all injectors on each side fire together so thats 1 3 5 & 7 all join up to fire at the same time, then its 2 4 6 & 8

so the 4 injectors on 1 2 5 & 7 side end up all joined togther, as does the other side, so you will end up with 4 x wires joined on each side, then the Power to the injectors

(all 8 of them) are ALL powered from the relay which means just one wire, and that is then made to go to all 8 injectors.

identify and remove form the kit the 3 wires you'll need - 2 x injector and 1 x power

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There are 2 pins on the injector, doesn't matter which wat around they are connected. now pull out just the loops of wires you need to use for the injectors

as per the diagram, leave everything else where it is, and also find the heatshrink.

So, we start with 1 3 5 7 Pulse wires, cut 4 equal lengths, and then some longer 4 wires for the power feeds.

Join the 4 injector wires together and add heat shrick a few inches from the end , same then on the injector wires.

Now join both these wires bundles together, having the power wires a few inches longer at the end than the pulse wires, and then heatshrink them together.

You now have 8 wire and 2 "ends"

Lay the ends a few inches away form the rear of the injection manifold, and use a zippy tie to hold.

Now, take 1 x of each wire and place near each injector.

Use more heatshrink to make them individually fit close to each injector and trim wires so each injector has some spare wire but not masses.

It will in about 1 hr look more like this :

post-22-0-39731800-1443106250_thumb.jpg

post-22-0-51455000-1443106269_thumb.jpg

post-22-0-80129500-1443106293_thumb.jpg

post-22-0-04442400-1443106310_thumb.jpg

post-22-0-26362500-1443106328_thumb.jpg

So, thats 4 injectors done !

Now, the same with the other colours for the injectors 2 4 6 8 and then you have 2 looms !

post-22-0-76909900-1443106414_thumb.jpg

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Now, you have 8 wires all the same colour which is power to the injectors, make a neat joining of these 8 then heatshrink them into one bundle of 8 :

post-22-0-50979600-1443106521_thumb.jpg

Now you can take this 1st loom made off and you have

8 injectors, 2 x differing wires to each, 4 injector feeds all together each side and

the power side of them as one bundle of 8 !

post-22-0-13833000-1443106549_thumb.jpg

Job done !

For me I now need to do everything else on the 90, so this will be placed on the 90s injection inlet, but again with zippy ties, but neatly with the wires being zippied in the position I wnat tm to end up with.

Next, is to do some of the other things in the engine bay, but these will now come through the bulkhead and into the cockpit.

The next things we will be adding to the loom are

the 8 x wires will be joined to 1 x wire and this all then brought through and placed near the relay it feeds from

The PWM control wires, 2 x of them, in the position the PWM is going to be, and to the ECU area ready for the plug

The 2 x wires for the CTS sensor, one to ECU and earth to ECU

same with the 2 x wires for the MAT Sensor, both earth and feed to ECU.

But to recap, the wiring was an hour ago like this :

post-22-0-37461800-1443106954_thumb.jpg

And with a marker pen mark whats done :

post-22-0-57459300-1443107011_thumb.jpg

So, these looms of wire have been pulled fom the kit ready to go to the 90.

post-22-0-17423800-1443107038_thumb.jpgpost-22-0-03700200-1443107049_thumb.jpgpost-22-0-05273200-1443107059_thumb.jpg

so thats PWM MAT and CTS Sensor, and frankly I'll do the TPS too at the same time, so thats 3 more Red yellow and Green:

post-22-0-15757100-1443107117_thumb.jpg

so, all these new wires, plus the made loom, plus zippy ties and the Diagram (Place dots on whats next to do)

post-22-0-21799100-1443107213_thumb.jpg

and this will be the next section :D

and now, when you look at the remaining amount of the kit it DOES look a lot less, it is !

post-22-0-21799100-1443107213_thumb.jpg

16 wires done for the injectors, now you have 2 x for CTS 2 x PWM 3 x TPS in your paws and the left over power and injector wires all going to the next stage, when this is done that will be 25 wires completed, which makes you sort of think its now as bad as it seems ?. Well it is - I hate wiring but I have with the help of other tried to take the fear and horror and complexity out of building your loom, more to come in the same picture heavy stylee as above, and yes it really is more of the same bit by biy step by step....

Nige

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  • 1 month later...

Update

Work has defo gotten in the way, so today with SWMBO with Family I had the workshop to myself, phone off and back on the wiring.

The process for me now, and the next step, is to add ALL the various wires from the kit, which go FROM the engine bay INSIDE the 90, at the moment

I am not worrying about any other wires.

So, these wires needing to be added are :

  • 3 x for the TPS which all go to the ECU- That's red yellow & Green
  • The 2 x Twin wires for the 2 x banks of the injectors Slate Green & Slate & Red - to ECU
  • The main power wire that feed the 8 x injector pins Brown & orange to relay in Cab
  • The CTS Sensor Black & slate and then the ground to ECU To ECU
  • the "VR" sheilded cable to EDIS 8
  • MAT sensor Red & Black and Ground to ECU
  • Red & Green - PWM to ECU
  • Then x 2 Power to Coil pack Centre Pins
  • and then lastly the 4 x Wires to each of the four coil ignitions.

The cables were again seperated form the Loom kit, and they were passed from the inside of the cab into the engine bay

The wires are all "Generous" so 99% will be shortened when pins and plugs fitted.

Some pics to help it make a bit more sense :

post-22-0-66906100-1446310444_thumb.jpg

All these wires are NOT needed yet, these are all INSIDE the 90, ie EDIS8 to ECU and to relays stwitched igntion etc, so placed out of the way

as it just makes things cleaer !..

post-22-0-80061800-1446310801_thumb.jpg

Each Wire in the kit is seperated and Labelled with Colour and Length and size so makes things easier

post-22-0-49301000-1446310094_thumb.jpg

Heres the Main Ignition loom, now laid out approx to where the avrious wires go

Zippy tied into a rough position.

As wires are added they are zippy tied to the assembly, and so it grows and takes shape.

Already here is the CTS & earth TPS x 3 PWM and MAT sensor and earth

post-22-0-01015300-1446310224_thumb.jpg

I have decided the "Main loom" is going through a Large existing Hole (which has a big grommet) on the 90s Bulkhead, and

its very worth while at this stage making sure the wires have a nice route and all going the same route vs getting mixed up

on different sides of brackets etc.

post-22-0-36129900-1446310326_thumb.jpg

These are the 2 x Injectors and 1 x Power, which need to be joined 4>2 and 8>1 again generous lengths so plenty to play with later

post-22-0-07769900-1446310393_thumb.jpg

CTS nice and long, easy to tie the extra long lengths up, but loom is now taking shape.

post-22-0-91291100-1446310571_thumb.jpg post-22-0-45493100-1446310590_thumb.jpg

And here is the Coil pack wires 4 x "Triggers" and the power cable x 2, and the VR sensor Wire

Now VR sensor wire added and others too

post-22-0-65659400-1446310613_thumb.jpg

post-22-0-13337600-1446310637_thumb.jpg

Nice long wires for the coil packs all zippy tied into a rough position ..

post-22-0-79499500-1446310668_thumb.jpg

Begining to now take shape as a loom, all quite neat and routing clear of obstacles, more zippy ties

post-22-0-90467900-1446310750_thumb.jpg

And THATS the engine bay sorted,

The Wiring Diagram show which ones (ticked) are in the ebngine bay, and then into the cab area

Tommorow I go to the cab area to position the various wires around the Cab into the rough positions they need to be at, which will be fun, as its a tad messy in there

Its really not as bad as it seems, once the wires are in the positions they need to take are zippy tied together the interior will clear

The routes are

Fuel pump

ECU

EDIS8

Relay Box

Ignition

Etc

As soon as you start laying and zippy tieing the routes the interior loom will take shape, the the ADDITIONAL wires around the insides can be added, but more tomm !

:D

Nige

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Righty Ho then.

Had a early start, and I'm having a early finish, only so much I can take fiddling with wires !

post-22-0-56687400-1446385391_thumb.jpg

Eeek, not looking any nicer than my memory of what I left !

Its better to do small "Chunks" of the loom as a group of mini projects, breaking it down and concentrating on each "Project"

rather than trying to do the whole loom in one hit (or it is if you hate wiring like me and are carp at wiring - er - like me :D)

so

This morning early early is the start of sorting of the wires in the cab area, which are shoved in from the engine bay

which is now done ready for plugs and connecting up.

There are 2 stages

1st - locate all the wires in there and group together into 5 "Mini" Looms - from the mass of the 1 loom coming in,.

The mini looms are

Wires going to the relays

Wires the the lambda Sensor

Wires to Fuel Pump

Wires to the ECU

Wires to the EDIS

So, each of these looms then need to be pointed to a rough location - just make sure you are generous with the looms

then when you start to really locate everything you'll find your wires are too long - not too short !

Locations

Edis Front of cubby Box / ECU (most probably lol) behind drivers seat (TBC !!) / Relays etc - up behind Pass seat

post-22-0-01128500-1446385317_thumb.jpg post-22-0-77414700-1446385269_thumb.jpg post-22-0-71420400-1446385256_thumb.jpg

I started by making "3" mini" Looms

Relays

ECU

EDIS

As the EDIS is central, thats where those wires started going, Relays on the passenger seat and ECU on drivers seat

Easiest is to get a loom started, so things like the 4 x Injector Wires, and the VR sensor Cable, the white and purple coil wires - these all are easy to fine, pull them out and start zippy tieing

them into the respective seperate looms

post-22-0-25857000-1446385553_thumb.jpg

you quickly will start to see 3 looms forming

ow, just pick ONE loom and contrate on finding wires for it, working through the diagram, I started with the ECU Harness, as its got the most and

some very clear colours, Like RED YELLOW GREEN TPS etc...so any wires in the can belonging to the ECU loom were collected up, untangled, given a clean route and zippy tied up

the 2 other looms just looped out of the way. By going from top to bottom of the ECU wires you find yourself systematically finding each wire in turn logically and not jumping about if you

go the other way around of "Wheres this wire go" etc, and that way can lead to wrong wiring.

post-22-0-47538400-1446385988_thumb.jpg

So, some time later I have a long ECU loom of wires

And then some zippytieing of the fully harness coming into the 90, and acrodd the floor...

post-22-0-18252700-1446386060_thumb.jpg post-22-0-89026800-1446386072_thumb.jpg post-22-0-16999000-1446386082_thumb.jpg

And making the 3 growing loom go in there right directions. Last pic here shows the EDIS 8 Loom - Next was the EDIS Loom,

thats the 4 x brown coloured Coil Wires, and the VR wires etc

post-22-0-24260900-1446386267_thumb.jpg

Next the relay loom, I just make 1 x loom for both relays, so thats the Brown & Ornage power injectors wire, and the Coil Wires etc

Now, when you have done this process and have you 3 looms, things are much tidier.

So, now we have to add all the other wires which are internally from one loom to another.

ie EDIS > ECU

ECU>Relays etc etc

And we have to add joiners for multi wire routes.....

So, 1st is Blue and yellowas an example - this goes FRom the RELAY to the ECU AND to the EDIS...

post-22-0-49559400-1446386375_thumb.jpg

Wires are run from Relay loom to the EDIS loom and the ECU loom to the Edis Loom, now we have a group of wires to join up.

And here I use an cracking little unit called a heatshrink solder bucket connector. These are available in a range of sizes, on the bit I used a red one, then for extra protection 2

covers of hat shrink, as per the pics, you must get the 3 bits on the wires and out of the way of the impending heat gun, and then bare back the wires and join them up, slide the heat shrink unit

over the joins so the solder lump is central, then heat gun it hard and the solder melts and flows to make a proper joint. DO NOT move the heatshrink over until its cool, when it is

1st bit of heat shrink, heat to shrink, let cool and repeat - I make the 2nd heatshrink a bit longer than the 1st

Your 3 way joint them looks like this

post-22-0-80411600-1446386724_thumb.jpg post-22-0-94340500-1446386737_thumb.jpg post-22-0-04700100-1446386751_thumb.jpg

post-22-0-22797300-1446386760_thumb.jpg post-22-0-29080400-1446386771_thumb.jpg post-22-0-03112700-1446386782_thumb.jpg

post-22-0-94158100-1446386794_thumb.jpg

Push back neatly into your loom and move to next Which is white and purple

Here you will have just 2 x wires going to the coil, from your relay loom

you need to cut the 2 x wires and then add 2 x more - 1 x for the fuel pump (driver seat area) and another for the Lmada Sensor (passenger seat area)

when done you will have 2 x wires coming from the relay loom, and then spliting into 4 wires 2 x for coils (already there, 1 x lamdba, and 1 x Fuel pump

same as before, 2 x heat shrink, but a Blue Heat shrink solder bucket connector, 4 in one side 2 the other, when done will look like this

post-22-0-12880200-1446387036_thumb.jpg post-22-0-28664400-1446387048_thumb.jpg post-22-0-59329300-1446387057_thumb.jpg

post-22-0-07414600-1446387065_thumb.jpg post-22-0-20919200-1446387079_thumb.jpg post-22-0-38265700-1446387087_thumb.jpg

post-22-0-77181200-1446387102_thumb.jpg

And again neatly pop into the looms..

Then there are the Blue and Pink, the Pink and other wires from ECU to EDIS, work through and you'll see the wires remaining dissappearing !

more zippy ties help form the loom, and each wire in does make it more solid looking, as a extar trick, use a zippy tie the wrng way around, it will

grip enough for what you are doing here but not lock so you can open it to add more wires etc...

post-22-0-15220600-1446387297_thumb.jpg post-22-0-19663800-1446387308_thumb.jpg post-22-0-43276600-1446387321_thumb.jpg

Now, I am using a HEATED Narrow band Lambda, so I needed a Blue and a Power to relay white purple, but I have added 2 x Thick Browns for the heater circuit, so my lambda loom as 4 wires

post-22-0-64877100-1446387440_thumb.jpg

So, you have now 5 looms

1 x lamda 4 wires, 2 x brown 1 x White purple etc etc

1 x Fuel Pumpm (Single wire !)

and 3 others.

Now just take each loom end in turn, look at the diagram and check off each wire in turn to check A) you have it in the right place and B) You actually do have it !

post-22-0-56641300-1446387559_thumb.jpg post-22-0-35569600-1446387569_thumb.jpg post-22-0-96111800-1446387574_thumb.jpg

When your happy you have all the wires in all the correct 5 looms, and tidy up more ties and thats the inside wiring AND the engine wires ALL in place !

post-22-0-57044700-1446387920_thumb.jpg post-22-0-15934700-1446387932_thumb.jpg post-22-0-49038400-1446387945_thumb.jpg

More to come in a while, but had enough of it for today

TOTAL time so far is 9 hours.....

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  • 3 weeks later...

New blingness via new toy...

Heatshrink thermal laser printer....

Took a while to work out software as it quite comprehensive / complicated !!...but can mark heatsrink with pretty much everything and anything! !

These when on will be further protected with a additional covering of clear heatsrink.

Have had a play and here's a test set including logo.

Heatsrink is the posh and spend your 3>1 ratio

Mmmmmmm blingy lol

post-22-0-18085400-1447794965_thumb.jpg

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Righty Ho it has lurched !

This evening saw my Grown up leccy guru Jon turn up to do some crimping, I have never ever really got to grips with crimping delicate terminals, I seem to turn into Mongo from Blazing saddles and crush and grunt...

But in the meantime the plan for the prototype labeling was sorted

The idea was / is

Red heatshrink on cables in an appropriate place

slide on the white lettered heatshrink over the top of the red slightly smaller

Then add clear heatshrink, and connect in a way so the rubber boot is over the end etc.

Harness tape will be added to the finished loom and I even have some prototype heat shrink TAPE on a roll to play with !

On coils packs have also added the cylinders which are for the coil as a handy ref !

Some pics which should explain and show :

post-22-0-95363600-1447968614_thumb.jpg post-22-0-46154200-1447968627_thumb.jpg post-22-0-15200400-1447968640_thumb.jpg post-22-0-27564300-1447968655_thumb.jpg

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All in all chuffed

Tonight was all injectors and a few other bits but gas board visit cut Mr Crimper short as he has no heating so shot off, only to find he still doesn't have heating

Warmer in my workshop than his house poor bugger :(

More soon

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  • 2 weeks later...
  • 3 months later...
  • 2 months later...
  • 3 weeks later...

This really helps break the build down into even smaller steps, have prepped the wires for my injector loom, next are all the looms going to the ECU.... Nige's kit has been a pleasure to work with till now.

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  • 3 years later...

One thing to bear in mind for anyone about to attempt this:

On 9/24/2015 at 4:00 PM, Hybrid_From_Hell said:

There are 2 pins on the injector, doesn't matter which wat around they are connected. now pull out just the loops of wires you need to use for the injectors

Technically the injector doesn't care, but the owner may in the future.... If you ever want to fit a multipoint LPG kit, this has to be connected on the negative side of the injector. If you try and connect it to the positive side, it won't work... 

So my advice would be: 

Pick a standard for when you put the injector plugs on. Then write it down :) There appears to be two manufacturers ways of wiring it up:

Standard : Pin 1 Positive, Pin 2 Negative 

Inverted : Pin 1 Negative, Pin 2 Positive

(Wiring loom side, I believe pin 1 is to the right when looking at the back of the connector with the metal clip at the top). 

It looks like LR use the Inverted standard from the factory. 

It may save you a lot of faffing around in the future. You can guess how I know this! 🙄

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There's a few things that a gas ECU can do that MS1/2 cannot - different stoich values for gas / petrol map, gas pressure / temp compensation, coping with wildly different injector dead times, auto fuel switching, that kind of thing. Probably nothing that wouldn't stop you from getting it working, but it's not as simple as it sounds. 

You can do it in MS3, which even has a settings for injector switching via relays, but very few people on here are running MS3...

 

 

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