idosubaru Posted April 6, 2006 Share Posted April 6, 2006 in doing a search it is suggested that all of these are interchangeble. someone told me the Turbo and non-turbo MAF's are not interchangeable, so i'm trying to verify this for my XT motor swap issues. i have an RX MAF, unknown (i believe 88 XT) distributor, and the XT ECU won't work but the XT6 ECU will. so turbo, non-turbo, MPFI and SPFI should all be interchangeable? Quote Link to comment Share on other sites More sharing options...
calebz Posted April 6, 2006 Share Posted April 6, 2006 so turbo, non-turbo, MPFI and SPFI should all be interchangeable? Disty - yes - 87+ MAF - Probably between MPFINA and MPFIT - not SPFI though ECU - Probably between MPFINA and MPFIT - not SPFI though PS.. still looking for that spare ECU for you. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 6, 2006 Author Share Posted April 6, 2006 okay, thanks. i have a SPFI disty coming so that's good to know. anyone know about EA82T and EA82 MAF? i was told by a very knowledgeable xt6.net member that he doesn't think they are the same. but in a search over here, it says they are interchangeable. Quote Link to comment Share on other sites More sharing options...
Subaru Jim Maple Ridge Posted April 6, 2006 Share Posted April 6, 2006 As long as the electrical connectors are the same, the MAFs are interchangeable. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 6, 2006 Author Share Posted April 6, 2006 As long as the electrical connectors are the same, the MAFs are interchangeable. is that a generic statement or you're sure the MAF's are interchangeable on subaru's? i ask because there are toyota and other MAF's that have the same electrical connectors. now that i think about it - i think subaru's run fine without the MAF connected. maybe i could try disconnecting it. anyone verify that? Quote Link to comment Share on other sites More sharing options...
calebz Posted April 6, 2006 Share Posted April 6, 2006 now that i think about it - i think subaru's run fine without the MAF connected. maybe i could try disconnecting it. anyone verify that? It will run, but I wouldn't qualify it as running fine. In my experience, it runs downright crappy Quote Link to comment Share on other sites More sharing options...
JWX Posted April 6, 2006 Share Posted April 6, 2006 it will run, but you can't drive. the dists might be the same 87+ but the connectors are different for 87, its a round plug instead of square like 88+. I don't see why the mafs shouldn't be interchageable, but I am pretty sure the ECUs have different pin outs, turbo to N/a. also I know an 87 won't work in an 88+ car, and vice versa. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 6, 2006 Author Share Posted April 6, 2006 it will run, but you can't drive. the dists might be the same 87+ but the connectors are different for 87, its a round plug instead of square like 88+. I don't see why the mafs shouldn't be interchageable, but I am pretty sure the ECUs have different pin outs, turbo to N/a. also I know an 87 won't work in an 88+ car, and vice versa. everytime i ask a question i get more confused! thanks for the input. this is for a 1987.5 XT Turbo vehicle (engine converted to non turbo). seems that should qualify under the 88+ umbrella right, it has the MAF and spider manifold. the distributor i got would not plug into my 1987.5 XT Turbo wiring harness. i cut the plug off something and installed it. is that an issue? so what pin outs does this 1987.5 Unicorn have anyway? who the hell came up with "87.5" anyway!!! am i looking at 87 and earlier stuff or 88 up. Quote Link to comment Share on other sites More sharing options...
calebz Posted April 6, 2006 Share Posted April 6, 2006 also I know an 87 (ecu)won't work in an 88+ car, and vice versa. I have heard that, but I have had an 87 an 88 and an 89 ECU in the wagon and it has worked fine:confused: Quote Link to comment Share on other sites More sharing options...
calebz Posted April 6, 2006 Share Posted April 6, 2006 the distributor i got would not plug into my 1987.5 XT Turbo wiring harness. i cut the plug off something and installed it. is that an issue? If your splicing was done right, it shouoldn't be an issue. if you look up under the housing on the disty, you will see a phillips head screw. unscrew that and the whole pigtail pops out, to be replaced by the one with the correct connector. interchangeability at its finest. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 6, 2006 Author Share Posted April 6, 2006 so would my 1987.5 Turbo XT Spider Manifold wiring harness be represented by the 1987 or 1988 FSM? i figured out the swapping of the disty harness using the screws by doing a search...but after i had already cut. whoops. off to do some checking tonight. anyone on that 1987.5 FSM wiring let me know.....87...or 88.....?? Quote Link to comment Share on other sites More sharing options...
JWX Posted April 6, 2006 Share Posted April 6, 2006 me and WJM tried an 88 and an 89 in his 87, and neither one would start it. and it would throw code 44 (wastegate duty), but that shouldn't have made it not start. never tried an 87 in a later car so I dunno about that. and the pin outs are different for 87 compared to 88-89. gary, this is for RX's as I haven't owned anything else EA-82t powered. I think the 87.5 was basicly an 88 and later, but I could be wrong. what kinda plug did you change? black and round or white/clear and square? Quote Link to comment Share on other sites More sharing options...
calebz Posted April 7, 2006 Share Posted April 7, 2006 Visual comparison with my 87.5 NA XT motor tells me that the wiring harness more closely resembles the wiring in my 87 wagon than the wiring on the 88 manifold I have here. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 7, 2006 Author Share Posted April 7, 2006 Visual comparison with my 87.5 NA XT motor tells me that the wiring harness more closely resembles the wiring in my 87 wagon than the wiring on the 88 manifold I have here. headache.... maybe i need an 87 ECU to get this thing to work? but then why the freak does the XT6 ECU work. what "differences" or resemblance did you notice? thing is - everything is 88 and up EXCEPT the body wiring harness. computer, engine, MAF, and disty are 88 and up. only the body wiring harness is 1987.5. i'll look for differences in the 87 and 88 wiring diagram portion of the FSM and see what i can find. thanks a ton kids. Quote Link to comment Share on other sites More sharing options...
subyrally Posted April 7, 2006 Share Posted April 7, 2006 i have another ecu sitting in my parts stash, actuall, i have two, i can bring em by some time to see if it makes a difference. let me know gary. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 7, 2006 Author Share Posted April 7, 2006 tim, i'll definitely try out another ECU. do you know what year/model they came from? i'd like a 87 or earlier at this point for kicks if you have one but i'll test anything at this point. Quote Link to comment Share on other sites More sharing options...
subyrally Posted April 8, 2006 Share Posted April 8, 2006 tim, i'll definitely try out another ECU. do you know what year/model they came from? i'd like a 87 or earlier at this point for kicks if you have one but i'll test anything at this point. 86 wont fit the harness from an 87 or newer car. but i have two 87 ecu's and an 86. Quote Link to comment Share on other sites More sharing options...
ausubaru92 Posted April 8, 2006 Share Posted April 8, 2006 From what ive understand 1984-86 use the 3 plug ecu, flapper MAF, vac advance disty (not optical) knock control unit seperate to ecu and boost or vaccum switches for the ecu. 1987.5-94 used a 4 plug ecu, hotwire MAF, optical disty, no pressure switches, and the knock control unit is incorporated in the ecu. And the 1987-87.5 was a slight variation of the 87.5-94 wiring system, so some things work and others dont (mainly because of different plugs and pinouts) I think that is how it works Gannon Quote Link to comment Share on other sites More sharing options...
the_postie Posted April 8, 2006 Share Posted April 8, 2006 i have run a turbo motor on a 4 plug na ecu[aus 88] all i did was swap the n/a dist and n/a throttle body onto the turbo engine and use the n/a hotwire afm,all these parts came off the mpfi na motor i took out of the car.With this setup you are missing a knock sensor and boost cut,but mine still ran fine.i know of one other car thats been running this setup for over 2 years and it runs fine.Just finished helping a mate to run this same setup hopefully his car will be a runner soon.There r 2 different part no's for the turbo 4 plug ecu here in aus. hope this helps Cheers Will Quote Link to comment Share on other sites More sharing options...
calebz Posted April 8, 2006 Share Posted April 8, 2006 With this setup you are missing a knock sensor and boost cut No fuel cut/overboost protection? I like it Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 8, 2006 Author Share Posted April 8, 2006 but i have two 87 ecu's and an 86. Tim - i think i am in need of a 1987 ECU. let me know if there's any time this weekend i can come pick it up - call me! been comparing FSM's. wiring is slightly different. still looking at it - i'm not a wiring diagram master. i think i read binary and hex better than this stuff! I have the 1987.5 Turbo Engine and Body wiring harness and the 1987 and 1988 ECU pin-outs are a little different so this could be my issue. All the ECU's i have are 88 and up....wondering if an 87 will cure my issues. (BUT STILL WHY DOES AN F'ing XT6 ECU START AND DRIVE THE CAR!?!?!?!?) thanks for the help, can't believe you all are still following this mess! Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 9, 2006 Author Share Posted April 9, 2006 the 1987 XT and 1988 XT wiring diagrams are different. the main sensor difference is the 87 XT AAV goes to ground and the same side goes to pin out #59 on the ECU in 1988. i tried mocking that up and inserting a pin for the 1988 ECU to work but it still didn't work. there are other minor differences like no EGR on the 1988 and no waste gate on the non-turbo motor and then some definite differences in routing between the engine and ECU but the rest of the ECU pinouts are quite close. but i'm going to assume this is too much to make an ECU swap feasible. and hope, however doubtful i actually am, that a 1987 ECU might run this thing. Also - the 1988 FSM lists NO knock sensor for the XT 4 cylinder. but it does list a knock sensor for the 1987 XT 4 cylinder. strange indeed. i thought all XT's 1988 and up had knock sensors. i'm going to assume from this that i need a 1987 ECU. Quote Link to comment Share on other sites More sharing options...
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