V8 Loom

Putting a 3.9 efi from a 95 disco in to a 89 defender to replace a 3.5 on twin su carbs.

I have the complete engine loom it includes everything including wires to stuff like starter motor, oil pressure switch, alternator etc all in one loom.

Is it best either to fit the whole loom take it back behind the dash and from there connect everything and strip back existing wiring to there.

Or is it best to leave all existing wiring to ancilliaries etc in place and only use the new loom for the efi bits?

Which is best way to do this?

Gerald

I would have thought merge the 2, and just take the EFI bits off the loom. But i may be proven wrong in a few mins

Idris said:

Putting a 3.9 efi from a 95 disco in to a 89 defender to replace a 3.5 on twin su carbs.

I have the complete engine loom it includes everything including wires to stuff like starter motor, oil pressure switch, alternator etc all in one loom.

Is it best either to fit the whole loom take it back behind the dash and from there connect everything and strip back existing wiring to there.

Or is it best to leave all existing wiring to ancilliaries etc in place and only use the new loom for the efi bits?

Which is best way to do this?

Gerald

Click to expand...

I'll tell you if you go introduce yourself first, Gerald.

Why destroy the loom binding just to remove a few additional wires.
Just fold and tape neatly to the loom, one day you maybe glad of an additional wire or two.

All old V8's must be donated to me for decommissioning its the rules!

Fit the entire engine loom, run it on the underside of the gearbox tunnel and mount the ECU behind the drivers seat.

There is only a few wires that you need to feed the rest is pretty much self contained.

Live, earth, ignition live, fuel pump feed.

Thanks for your replies especially to Tonks 4x4.

Gerald

You'll also be needing oxy sensors and cats and speed transducer. AFAIK because the engine is 1995 for MOT exhaust should be fitted with cats and you'll need to pass full cat emission test.

He is using the original gearbox so there is no speed transducer.
The lambda sensors can be used as they are part of the Efi harness.

As far as the cats, I would suggest don't fit them and just act ignorant when it comes to MoT time. Save the cats just incase they make you use them.

classic kev said:

You'll also be needing oxy sensors and cats and speed transducer. AFAIK because the engine is 1995 for MOT exhaust should be fitted with cats and you'll need to pass full cat emission test.

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2002 vehicles is the full cat test, up to then it's the BET test.

Have fitted the lambda sensors and have an "in line" speed senor ready to go in to the speedo cable.

Not sure what to do about the spider.

Gerald

Tonks4x4 said:

He is using the original gearbox so there is no speed transducer.
The lambda sensors can be used as they are part of the Efi harness.

As far as the cats, I would suggest don't fit them and just act ignorant when it comes to MoT time. Save the cats just incase they make you use them.

Click to expand...

The speed transducer it driven by the transferbox on a disco 1 so it doesn't matter what gearbox is fitted.

Idris said:

Have fitted the lambda sensors and have an "in line" speed senor ready to go in to the speedo cable.

Not sure what to do about the spider.

Gerald

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Don't fit one, it wont work unless your fitting the rest of the security system anyway 95MY discos don't' have a 'spider'.

I never remembered the speed transducer being part of just the Efi harness?

There is no need for a speed signal.
The original transfer box will have the original speedo cable that feeds the original defender speedo?

Discool beat me to it

The loom has come with what looks like a spider.

Gerald

Idris said:

The loom has come with what looks like a spider.

Gerald

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OK but it's not from a 95MY disco, 96MY maybe introduced in June 1995 which was fitted with a passive immobisiler.

The efi loom is a separate item to the vehicle loom.

or at least it was on my 3.5 efi

that would make things a LOT simpler because you can leave all your original wiring and the efi just sorts out the injectors and sensors, you may need a supply to the coil

personally wouldnt fancy trying to fit a complex 3.9 disco full loom to a 90, there will be many many more things than you need, try to extract the 14cux look components (start at the ecu plug) and see what you have

get some pics up of what look you have got

cheers

ah just read you are replacing a v8, perfect, just fit the efi as a standalone system, trust me on this it will be much easier to leave original oil pressure an water temp sensors and starter wiring, you already have coil wiring too.

14cux loom has a white/black wire that needs to connect to coil negative through a resistor, and then the loom should have a single plug where it joins to the main vehicle loom and receives power, earth, speed signal, and sends fuel pump feed etc.

hopefully the 3,9 didnt have a more complex version, if so, i would find a 3.5 14cux loom as it is fully standalone.

having just fitted megasquirt i am fairly well versed on 14cux and rover v8 efi wiring!

Tonks4x4 said:

I never remembered the speed transducer being part of just the Efi harness?

There is no need for a speed signal.
The original transfer box will have the original speedo cable that feeds the original defender speedo?

Click to expand...

I think you will find on hotwire injection the speed transducer is needed - the ECU looks for the signal so it knows when the vehicle is moving and so switches the idle stabilisation on and off, this is done in conjunction with the throttle potentiometer. I believe an EFI will run without the speed transducer but you will have idle problems.