Megasquirt V3 wiring Loom

[Mike Lloyd]

Hi

I am currently trying to make up an engine wiring loom for the Megasquirt V.3 ( just built) to suit a Zetec running standard injection.

I am hoping to use stock sensors where possible.

Fuel Pump, Injectors, crank sensor, coolant and intake air temp, TPS look 'relatively' straightforward.

I have no O2 sensor but assume I can run without? I am not sure how to link up a Fast Idle valve?, Stepper IAC? or  connect in the ignition module / output  

I have looked on the megasquirt website and found the wiring diagram, the forum just scares me  

Has anyone made a loom for a standard zetec injection set-up?

[deano.1]

Looks to me that you wire the neg to your FI valve to term 31, you should be able to run without an O2 sensor (just make sure all the settings are correct) and yes i have made a loom up!

I'm not too familiar with V3 though (i couldn't use a FI valve with V2.2 with EDIS conversion)

HTH a bit

Cheers, Deano

[Mike Lloyd]

Thanks Deano

Am i right in assuming that the FIdle and Idle speed control valve are the same thing

[deano.1]

Thanks Deano

Am i right in assuming that the FIdle and Idle speed control valve are the same thing

Yes mate  FIdle = Fast idle  

Have fun  

[Kevin Wood]

I wouldn't bother with the FI valve. I'm not sure what type are fitted to the Zetec but if it's a stepper one you can only control it with an MSII. It will drive a solenoid valve but the transistor on the board may not be up to it, depending on the impedance of the coil.

Is there a manual throttle stop adjusting screw?

I would be tempted to just set the idle up with that.

Failing that, if it's a stepper IACV, open it up and turn the motor manually until you find a setting where it idles happily.

You'll find it idles a few hundred RPM slower when cold but with no loads like PAS and AIR CON it'll be quite happy and shouldn't stall on you.

Kevin

[Peter M]

Westfield used standard ford injection on a model they called their summer madness kit.This set up did not use IACV instead to get the engine to idle correctly they basically used the throttle stop adjust screw  to get the correct idle speed.

[Mike Lloyd]

Thanks for the Info, i'll try and get away without FIdle to start with.

I'm going to wire the engine loom through an additional fuse box to accommodate fuses for injectors / ecu and fuel pump, does this make sense or can you use in-line fuses?

Thanks

[deano.1]

I used a seperate fuse box for my engine wiring, seems a bit more profesional to me!

[Kevin Wood]

I did the same. VWP, among others, sell fuse boxes similar to the ones which come on a Westie loom. I used a 4-way box, one fuse for each live feed to the injectors (5 amps each, driving 2 low-z injectors), one fuse for the 12v feed to the MS ECU (5 amp) and one for the feed to the WB Lambda controller (5 amp). The fuel pumps I ran from the existing fused circuit in the loom but I added the fuel pump relay contacts into the circuit where the break-out connector for the immobiliser is.

The whole lot is fed straight from the +12v line, switched by a relay that's fed from the ignition switch.

I prefer not to have fuses and relays in-line in the loom because they invariably rattle around and get damaged / loose connections / fill with water, etc. Having them secured (in my case under the scuttle behind the instruments) also makes them easy for find when you have a problem. (not that I have in 3+ years of Megasquirt use).

Kevin

[Mike Lloyd]

Thanks Kevin / Deano

I was thinking along these lines, it is all seeming a little less daunting now.

This will probably change when it comes to turning the key though.

[deano.1]

Mines pretty much the same as Kevins, just don't wire the coils the wrong way round and spend a week wondering why the timing seems so far out like i did      

[Chasmon]

You can buy a Relay/Fuse board from the same source as the Megasquirt. Makes it all quite tidy...