ECU Query/Help

[moleymolo]

Following on from my micra for hillclimbing I have a slight problem as I have got to the ever dreaded electrical stage now...

I have stripped the dash out fully as the replacement will be ally with a standalone starter switch/ignition button.

I'm a bit unsure as to what wires I need to keep as theres waaaay too many of them for my liking.

Been told that all the wires that come off the ECU connectors (that DON'T go through the bulkhead) are just wires for lights and fuses etc.

So my plan is to cut away those connections and tape over them to save going through all that wiring.

Trouble is, Im not sure what I need to keep or replace to run the engine properly.

Like I say I have a standalone starter switch/ignition and all I want at the end of the day is to run the engine without having to go through thousands of wires. It won't have any lights or horns etc. Purely JUST the engine and management.

Any help? :wasntme:

 

[frank]

i would say tread carefully MM fwn the ones that run through the baulkhead will be sensors/feeds/earths etc eh, but the fuelpump relay is inside the cabin as is the speed sensor, has yours got nats ?

 

[moleymolo]

nats?... its a 1997 car. Not sure what reg it is as ours is different over here...

 

[frank]

is there a red chip in the key MM ?

 

[moleymolo]

Not that I know of, the key I got is almost like a house key! got a bit of plastic around the keyring hold but thats it...

 

[Low Rider]

The ECU loom is a complete seperate unit from the main loom, the only part not relating to ECU control is for the wiper control relay mounted on the back bulkhead near the wiper motor which is bundled in the main loom. For ECU control you would need to trace certain wire runs from the ecu which tie into the block connectors under the centre console. An ECU wiring diagram with pinouts makes these relatively easy to trace out.......for example fuel pump relay, (located behind the removable panel drivers side footwell infront of the door hinge), cooling fan relay, (think located in the engine bay), grounds, ignition +12v etc would all be needed.

I'm sure there are more but remembering all of them is tricky, especially since my aim was to remove the old ECU loom completely to make way for an Omex setup........so I sort of did the complete opposite

 

[frank]

it sounds like it does,nt have nats eh MM, but i would still be very wary of cutting any wires (for the sake of 2kg in the frontend of a fwd car fwn) the ecu gets all sorts of inputs (neutral switch, speed sensor radfan, even the heater motor according to the daig)

 

[moleymolo]

Cheers for the replies.

I am going to state that I am not bothered by keeping lights, horns or heater modules. I am only after the controls/ecu for the engine to work only. Anything related to the dash itself im not keeping, as the dash will be non-existent.

Basically, wiring for the ECU and engine sensors...

 

[moleymolo]

One thing I forgot to mention my intention is to have a seperate switch for the fuel pump so the ECU would only control the fuel injection and running of the engine once started

Ignition, fuel pump would be one switch: Ingtion "on" on would activate fuel pump at the same time.
Engine start would be another switch: Purely to turn the engine over
Fan, windscreen wipers would be another switch.

Have ran this system before however I didnt install it. Although it was running twin weber 40's...

 

[frank]

the fuelpump system is designed to cut out after 5 secs if there,s no rpm signal MM (for safety) which you might have to bear in mind

 

[moleymolo]

but if its on a seperate switch it should just keep pumping fuel. Obviously the trouble will be if it keeps pumping without any ignition... It run straight off the battery into the throttle body/carb until ignition and battery has been switched off...