[Mk2] [NA] Rev 3 engine clips question.

[rover19376]

Hiya folks.

Hoping someyone knows the answer:

Looking at converting my old rev 1 to a rev 3 engine.

I have a rev 3 import ecu but someyone has offered me a rev 3 uk engine clip.

I have one person saying uk and import rear clip are the same and one saying the pin outs will be different.

I have no idea myself, but anyone out there know?

Thanks for any help.

[alanmr2turbo]

Import and UK ECU's are different and will need repinning.

Just source a UK ECU and save yourself a headache. Or put an import engine loom on the UK Engine and use your ECU

Also get yourself the passenger side loom to make life easy. This also should match the engine (uk or import)

[rover19376]

mine is a rev 1 import , but if i were to just get the uk clip and ecu everything should still match up ok?

[alanmr2turbo]

nope

[rover19376]

ok, i'l continue my search for an import clip then

[alanmr2turbo]

and dont forget the passenger side loom as well

[Rogue]

Import and UK ECU's are different and will need repinning.

That's incorrect I'm afraid - Japanese and UK 3SGE ECUs are pin compatible up until revision 4. You can take any Japanese ecu and swap it for a UK one of the same revision and vice versa. The only key difference is that JDM versions had a speed limiter at 180kmh. We routinely swap UK ECUs into G-Limited based race cars to get around the speed limiter.

At Revision 4, UK ECUs were fitted with transponder immobilisers. It is possible to make a revision 4 / 5 engine and loom work with a revision 3 ECU by repinning it.

OP, you will have some wiring work to do simply because you're putting a revision 3 engine into a revision 1 chassis. Pay particular attention to the 12v power supply to the igniter and the fuel control circuit.

[alanmr2turbo]

Oh dear. So going by what you have just said that ALL pre REV4/5 ECU's are interchangeable. How would a REV1/2 UK be a straight swap with a REV1/2 import? The import REV1/2 has the cold start injector so how would the UK ECU run that?

If he does the conversion my way he wont have ANY repinning to do.

[Rogue]

Oh dear. So going by what you have just said that ALL pre REV4/5 ECU's are interchangeable. How would a REV1/2 UK be a straight swap with a REV1/2 import?

1) Unplug import ECU
2) Plug in UK ECU

The import REV1/2 has the cold start injector so how would the UK ECU run that?

The cold start injector is not controlled by the ECU. It's controlled by the cold start injector time switch.

If he does the conversion my way he wont have ANY repinning to do.

If he uses the passenger side chassis loom from a rev 3 import into his rev 1 import then I agree. If he uses a UK passenger side chassis loom then at the very least he'll need to re-route the fuel pump power supply. If the car is fitted with ABS then the power supply for this will need to be re-pinned in the footwell. In the unlikely event that aircon is retained then some thought will need to go into the wiring for this as well. The issue of the wiring differences for the speedo should be neatly side-stepped by retaining the mechanical system.

[Nik_L]

Hmm kinda glad this has popped up.

I have a UK Rev 2 as my daily and an import G-limited that im breaking. Has a full running engine. Would it be worth the hassle of swapping the engines just for an extra 12bhp??

Would it be worth swapping the ECU's over?? Or did they run the same map?? Or would it be pointless putting an import Rev 3 ecu on a UK rev 2??

[rover19376]

Oh dear. So going by what you have just said that ALL pre REV4/5 ECU's are interchangeable. How would a REV1/2 UK be a straight swap with a REV1/2 import?

1) Unplug import ECU
2) Plug in UK ECU

The import REV1/2 has the cold start injector so how would the UK ECU run that?

The cold start injector is not controlled by the ECU. It's controlled by the cold start injector time switch.

If he does the conversion my way he wont have ANY repinning to do.

If he uses the passenger side chassis loom from a rev 3 import into his rev 1 import then I agree. If he uses a UK passenger side chassis loom then at the very least he'll need to re-route the fuel pump power supply. If the car is fitted with ABS then the power supply for this will need to be re-pinned in the footwell. In the unlikely event that aircon is retained then some thought will need to go into the wiring for this as well. The issue of the wiring differences for the speedo should be neatly side-stepped by retaining the mechanical system.

as the air con has long lost it's gas- i'm not fussed on losing the air con.

and will be fitting my rev 2 gearbox that i fitted the rev 1 mechanical speedo too.

[Rogue]

I have a UK Rev 2 as my daily and an import G-limited that im breaking. Has a full running engine. Would it be worth the hassle of swapping the engines just for an extra 12bhp??

Only you can answer that question! If you were using it for racing where every bhp counts then the answer would be absolutely yes, but it's not a massive leap for everyday use. The extra power is all at the top end so you wouldn't really notice a huge amount of difference unless you were pushing on.

That said, it's probably the cheapest way to gain a genuine 12bhp.

Would it be worth swapping the ECU's over?? Or did they run the same map?? Or would it be pointless putting an import Rev 3 ecu on a UK rev 2??

There'd be a lot of work in making a rev 2 ECU run on a rev 3 engine (and you'd need to swap other components like the igniter) and the map would be less than optimal. In short, it would be worse with the later ECU than the earlier one!

[Rogue]

If he does the conversion my way he wont have ANY repinning to do.

Just also remembered that the passenger chassis loom extends to cover the rear lights so you'll have the hassle of chopping and swapping connectors for the clusters and rewiring the reverse lights unless you also switch to rev 3 rear lights at the same time.

[Eksterminator]

At Revision 4, UK ECUs were fitted with transponder immobilisers. It is possible to make a revision 4 / 5 engine and loom work with a revision 3 ECU by repinning it.

I got probably rev 4 engine from Celica 6 as a donor for my MR2 (looks like rev3 but got EGR so I assume it's rev 4), but haven't got ECU for it. It's got 4 plugs on wiring loom.

What ECU will I need for it ? Will 96-97 ECU not run on it due to the immobilizer ? Would I need some extra immobilizer pieces ?