Hey all! First post here, be nice. 🤣
Vehicle is a 1994 4th gen Honda prelude with a H23a1 engine, OBD1 ausdm. Engine (h22z1) is from a 1999 5th gen honda prelude OBD2A ausdm.
So for a little context before I display my problem… I own an AUSDM 94 honda prelude (OBD1 H23A1), it recently blew its engine, so I brought a H22Z1 out of a 99 plate 5th gen prelude (OBD2A) and got the ecu from a 97 plate 5th gen H22A4 (Also OBD2A).
The issue I’ve come across is that from 97 onwards, all prelude ecus have a built in immobiliser that is wired into the body loom. Seeing as how I’m still using my 4th gen body loom, I don’t have the bits necessary, nor do I have the patience to wire it up into my loom if I don’t absolutely have to find the stuff and wire it in…
My questions are…
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Is there a way to trick the ecu into thinking it has the transponder signal even though it doesn’t have the signal?
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Is there a reliable way to remove the circuit inside the ecu? I have a soldering iron and such. Could I remove it myself safely? If so what do I need to put in its place?
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If I do need to wire in all the components for the immobiliser, can I use aftermarket stuff (for example, a keyless remote with a transponder and reciever to turn the car into push button start or even just to get it to turn the ecu on so i can turn key start it… would an aftermarket antenna and memory drive to store the key codes/frequencies work, Or does it need to be the factory stuff only?
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If question 3 is viable, is there a way for me to automate the steering lock with the push button start. Think the new car keyless systems, where the key doesnt have to be in a specific spot, just inside the car. Push for ignition, again for on. Could I use the electrical signal from the car going into ignition from the push button, and use that electrical signal to unlock the steering lock?
My thought process from question 3 is that I can possibly facilitate the retrieval of the factory antenna and reciever (if it’s not in the ignition barrel), and possibly make it work by wiring the stuff in, but that’s a long, dangerous and tedious process, with a lot that could go wrong.
I know this was a lengthy post, so far the car runs and drives on the obd1 ecu, it’s just down on power, and it’s missing on partial throttle, so I don’t need this to drive the thing, I just want to know if there is an alternative to buying a 2 grand ecu to manually tune the thing if I don’t actually need to.
Thanks all. Hopefully you all can point me to victory. 😅😆
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I’ll try to answer this, here goes.
Why not just rewire the distributor and use the ECU that you have in the vehicle?
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there is a back door to bypass the immobilizer but you need to know the Vin from the vehicle it came from and your Honda dealer can provide you with the “brake code”. Unfortunately This is only a temporary bypass though to get you to the dealer without a tow truck. Otherwise the answer is nope.
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Jesus, no.
As someone who does surface mount repair and all sorts of reverse engineering and computer hacking, I can tell you with certainty that there’s no way on God’s green earth that you’re going to be able to do what you describe.
Ditto for 3 and 4.
Legit PDFs of your FSM including wiring diagrams
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