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G3 4 cylinder wire in how to for mk1 1.8 Eunos/mx5/miata


steveb

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I want to buy a G3 for 4 cylinder ecu for my 1996 1.8 Eunos turbo, I have a few questions :- 1. does the ECU have an on-board MAP sensor? 2. What air intake temp sensor should I buy? 3. What boost control solinoid should I buy? 4. Are wire in instructions available for the G3 into the Euno, its a mk1 1.8 1996 car? is there anything else I need to fit this ECU? Please help Steve B

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Ok I've found the answers :- It does have an onboard 2.5 bar absolute sensor good for me :) I can get a bosch AIT sensor with it :) I can get a boost control solinoid with it :) I can get a adaptlink so its effectively plug and play :) all fantastic ! But two new questions, the Eunos uses batch injection as stock, can I convert it to sequential injection with the LEMG3? Does it need low or high impendance injector or does it not matter?

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LEM G3 only runs batch (usually called grouped) injection, so sequential is not an option.  To get sequential you need to go to a LinkPlus wire-in.  There is no plug in adapter for the LinkPLus but.

The AdaptaLink is designed to run with high impedance injectors.  If you want to run low impedance injectors, then you will need to wire in ballast resistors (which can also be supplied if required).  Ballasts can be wired into the engine bay or into the loom between the adapter and ECU.

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So no sequential injection, not the end of the world I was hoping to run sequential to improve emmissions for the yearly tests, i'll still be putting the CAT back in then. I have spoken to someone about the injectors I have on order and he thinkes they are high impedance the same as stock injects? So I shouldn't need the ballasts. Thanks for your help I'll pace the order steve

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I just received my G3 & plug-in adapter, all looks fine. Only question I have so far is the boost control solinoid. The G3 manual is for general wire in installation and it says:- "Auxiliary Output connects directly to one terminal on the solenoid to provide an Earth. The other terminal on the solenoid must be connected to an ignition switched (key on) 12 V source" but as I'm using the miata adapter, where do I connect to?

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Well, since the adapter was only ever designed for factory applications, there is not wire specifically assigned for a wastegate solenoid.  Note that there is a pad on the adapter board for Auxiliary Output 2 that can be soldered to as this channel is unused on the AdaptaLink.  You will have to set up Aux 2 in PCLink for Boost Solenoid.  Otherwise cut the Aux2 wire between the ECU and adapter and wire to that...

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  • 2 weeks later...

Stuck again, can you suggest a 12v switched supply for the boost control solinoid on the turbo side of the engine bay? The ones suggested on the mx5 clubs appear now to be dead since pluging the G3 in, I'm assuming the original middle ECU plug thats no longer used was the stock diagnostics port inputs, thats were people are suggesting I take power from.

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Yep confirmed 8/95 the ECU pinouts totally changed on mx5/eunos/miatas becoming 3 plug and the 2 plugs 26pin & 22 pin that remained the wires were all jumbled up. So the Adaptalinks not so plug & play, going to have to try and compile pin diagrams and un-pick the plugs on my loom and put them all in the pre 8/95 configuration. I guess LINK wasn't aware of this, so wouldn't have an appropriate 8/95 - 12/97 1.8 Eunos pinout diagram?

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The AdaptaLink you purchased is a replacement for our older MaiataLink ECU's.  These ECU's and the AdaptaLink were all designed to be used as a direct plug-in replacement on two plug ECU vehicles.  The modification required for fitting to a three plug ECU was often done for our old ECU's.  Unfortuneately this has not been made clear.  I also completely missed this when you gave me the year of your car!  We have considered doing an adapter board for later ECU's but have had little demand yet.  It would be my recommendation to not re-wire the factory connetcor to fit the AdaptaLink but directly wire the LEM G3 ECU directly.  Please contact me directly [email protected] to continue this discussion...

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