matts87glsedan Posted July 9, 2011 Share Posted July 9, 2011 hi again the gl sedan got forcibly retired, so ive been driving a 1990 legacy 2.2 automatic for the last couple of years. its been a good car, i swapped out the blown factory airbags, and did a 2.5 inch lift, plus a few other things. i do about 700km /week of commuting and some light wheeling on weekends. 1.30/L gas prices have got me thinking about switching to propane, using the technocarb ESIP system. I like this one because it comes with what looks like a pretty sweet engine management program (although i have no experience with them), and the company is located close to me. the trick is, they require an OBD2 ecu. So, could it be as simple as installing the ecu from a 95 2.2 legacy automatic? My mechanic is running a newer rs with a 1990 ecu, i am hoping it goes both ways. anyway, im off to the junkyard today to pick one up, but i thought i would check in with the board and see if anyone has experience mixing and matching ecu's. thanks again for any info. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted July 9, 2011 Share Posted July 9, 2011 The wireing connector for the ECU is completely different, but in theory it should mostly work. The two primary differences besides the ECU wireing connector will be the rear O2 sensor, and the OBD-II diagnostic port itself.... and of course the pinout nightmare that's going to result when you have to swap the ECU connectors. I don't envy you on that job . I've stripped a lot of harnesses for swaps but I've never tried what you are proposing. Would be a whole lot of work. However you do it - skip the '95 ECU as it's got some real strange wireing... go to the '96 version. GD Quote Link to comment Share on other sites More sharing options...
matts87glsedan Posted July 9, 2011 Author Share Posted July 9, 2011 hmm thx GD i wonder if it would be easier overall to take the entire harness from the '96 along with the ecu, and then try to match all the plugs up under the hood. i guess i will have to take a bunch of pictures of both the OBD1 and OBD2 underhood and compare them. unfortunately this is the only ej that ive owned, so im a bit clueless about their different incarnations. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted July 9, 2011 Share Posted July 9, 2011 Well - swapping the harnesses complete would probably be *more* work because they changed where the plugs are located and added another hole in the firewall where the plugs go through that attach the body harness to the manifold sub-harness. On your '90 it's next to the battery but on the '95 and up it's on the back of the engine on the passenger side - opposite the starter basically. Also other things are in radically different places - the ECU on the '90 is under the dash basically right in front of your left knee. The '95 and on cars have the ECU under the carpet on the passenger floorboard! Basically the whole wireing harness is laid out differently. I think you should rethink your approach - have you considered Megasquirt? You could whip up an adaptor that would allow you to plug into the existing ECU connector and run the car from the open-source, stand-alone MS box - then you can tune it for whatever you want. GD Quote Link to comment Share on other sites More sharing options...
matts87glsedan Posted July 10, 2011 Author Share Posted July 10, 2011 you may be correct about re thinking things. i was hoping to get away with minimal expenses over and above the cost of the propane system and its computer/tuning software. having to also set up megasquirt to get it to operate would most likely blow my budget all to hell. I think ill have to speak more with the technocarb rep about why their system requires OBD2. in the installation PDF , it mentions installs on cars not having on board diagnostics at all ... although if it comes down to it, i think i'd be willing to tackle re-pinning my cars wires into the new cars ecu plugs. i have the complete propane system out of an old taxi (tank,hoses, vaporiser, mixer, carb , solenoid valves, etc) - so i could also probably try to make that work with a distributor - but i liked the idea of having a tuneable computer and multipoint fuel injection. Quote Link to comment Share on other sites More sharing options...
nipper Posted July 10, 2011 Share Posted July 10, 2011 It would probably be much easier to get an OBDII engine and get the harness and put that in the car. Converting an engine from OBDI to OBDII is possible in theory, but anything is possible with enough time (sometimes money) and lunacy. Quote Link to comment Share on other sites More sharing options...
matts87glsedan Posted July 11, 2011 Author Share Posted July 11, 2011 It would probably be much easier to get an OBDII engine and get the harness and put that in the car. Converting an engine from OBDI to OBDII is possible in theory, but anything is possible with enough time (sometimes money) and lunacy. true. even easier than that would be to just buy a newer car, which believe me, i would do if there was a budget for it. this one has been run at highway speed into the ditch and under a barbed wire fence lengthwise, the power locks dont work, the windshield is cracked, the interior is shot, etc. but unfortunately, the conversion kit is 1000$ plus tax , and thats already money i dont have. so i was really hoping to make it work in this car. but thank you , i know its not the ideal way to go about it. so i guess the next step is to find a '96 computer from a 2.2 automatic, and a pinout of it , and my '90. i see many little masking tape flags in my future. wish me luck. and hopefully find a harness from a '90 auto as well, so if i eff it all up, i can swap the original back in. Quote Link to comment Share on other sites More sharing options...
eulogious Posted July 12, 2011 Share Posted July 12, 2011 I would suggest making an adapter of sorts, so you don't mess up your original wiring, and you can then just go back to stock really easily. Just get an ECU, unsolder the connector off the board, then get the ecu plugs off a car that uses the same ecu you are using, and just match the wires up. Then you can plug your exsisting plugs into the new adapter, and then plug the new ecu into the other end of the adapter. Then you don't hack up your original wiring. Does that make sense? Here's a link to the megasquirt example of the same thing. This is for a legacy: http://www.diyautotune.com/catalog/diybob-breakout-adapter-nippondenso-76-pin-p-411.html I just got a MegaSquirt, and I am going to be squirting my MR2, and this is what I am going to be doing for it. I am making an adapter like I described so I can avoid hacking up my wiring. If I had a $100, I would just buy one like I linked to, but I would rather save the money and make one myself. Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted July 12, 2011 Share Posted July 12, 2011 (edited) the pin outs for a couple of ECUs have been posted, they are in the FSM. and an adapter would be a really smart way to go for me. that way when i screw it up the car still runs. it also means that your car is not ''down'' during the process. you can keep driving it untl you are ready to make the swap. i have no experience with early 90s ECU, and only some limited experience with the ECUs from the late 90s. but from what i have seen, they don't change a lot from one year to the next but they do change. in 95/96 they added the wires / pins for the obd2 port. and in 97 / 98 they moved ? some of the sensor pins. but as long as the wire connectors are the same it should be pretty straight forward. the engine will likely run with the newer ECU (maybe not, but i have seen no evidence that they ''moved'' major component pins). the 98 outback will run with a 96 lego ECU but with a constant cel (purge flow fault i think, p1104 & p0441). with a 97 ECU it will run but with different codes (knock sensor maybe, p0325). Edited July 12, 2011 by johnceggleston Quote Link to comment Share on other sites More sharing options...
matts87glsedan Posted July 16, 2011 Author Share Posted July 16, 2011 that adapter is an excellent idea - but it turns out that i have been jumping the gun on the ecu swap. I spoke to a tech from technocarb today, to ask him why specifically the car had to be obd2, and he said that i didnt even have to worry about it (even though its written on the front page of their website ) . it was just a quick conversation so i need to get some details via email, but it sounds like the whole computer change is unnecessary. the bad news was that the TC control module isnt actually a stand alone ecu (too much to ask i guess), so i may be doing the adapter down the road anyway. thanks for the replies though, the forum continues to come through Quote Link to comment Share on other sites More sharing options...
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