stickedy Posted September 4, 2006 Share Posted September 4, 2006 The title says ist all: Will an Turbo-ECU (MPFI) work in a non-Turbo (also MPFI)? The Turbo car is built 1989 and the non-Turbo 1992 or 1993. This question is related to that thread here: http://www.ultimatesubaru.org/forum/showpost.php?p=507459&postcount=1 The Turbo-ECU is currently in my car but it' not used anymore since the EA82T engine fails and there is currently a carbed EA82 installed. So I could pull it - when it's supposed to work fine - and push it in that other car to drive it home, about 250 Miles. And how fast can you change the ECU? I haven't done that yet... Thanks! Link to comment Share on other sites More sharing options...
ausubaru92 Posted September 4, 2006 Share Posted September 4, 2006 Theoretically you should be able to. Im sure someone here has done it before. The ecus are basically the same, except that the turbo ecu has a knock control function, wastegate control and possiably a larger fuel map. The 87+ ecu doesnt have a boost sensor like the previous 84-86 models did. I cant see why not. Link to comment Share on other sites More sharing options...
TomRhere Posted September 4, 2006 Share Posted September 4, 2006 Kinda recall a thread from a year or two ago about this subject. IIRC, there's a jumper wire that tells the ECU if the car is Turbo or not. If that is true, and if the connectors are the same, it should work. Swapping ECU's isn't a big job. Disconnect battery..... Couple screws to drop the panel below steering column, 3 nuts to loosen that hold ECU, slide it out, un-plug connectors, reverse to install. I would give the wiring harness a good looking over to check for damaged wires or components first. You could fry the replacement ECU if something is FUBAR.. Link to comment Share on other sites More sharing options...
stickedy Posted September 4, 2006 Author Share Posted September 4, 2006 Sounds good! And of course I will check the wiring first to be sure not to damage my precious ECU ECUs are rare here in Germany - as everything for those cars... Link to comment Share on other sites More sharing options...
ausubaru92 Posted September 7, 2006 Share Posted September 7, 2006 If the ecu is 87+, there is no jumper for the turbo Im pretty sure a few people have done it Link to comment Share on other sites More sharing options...
stickedy Posted September 21, 2006 Author Share Posted September 21, 2006 So, the car is at home and I had to use my EA82T ECU. Too make it short: It works! But not perfectly... The engine fires on instantly, got no problems. But when accelerating, at some point there is very few power available but when getting after this point, It's fine and runs OK. The "check engine" light is on, will check the ECU code now I drove about 400 km with this ECU, so you can do it if no real replacement is existant. Link to comment Share on other sites More sharing options...
daeron Posted September 21, 2006 Share Posted September 21, 2006 +1 for the whole thread. congratulations on your successful experiment, and thanks on behalf of the worldwide subaru community. Now we know, and knowing is half the battle. Please update if you discover any damage to the ecu or any other "catch" that would cause you not to do this again. oh, and good luck with the new car. Link to comment Share on other sites More sharing options...
zukiru Posted August 24, 2008 Share Posted August 24, 2008 old thread I know but what was the code?? Link to comment Share on other sites More sharing options...
stickedy Posted August 24, 2008 Author Share Posted August 24, 2008 If I remember correctly the codes were related to the knock sensor (as it simply doesn't exist at that non-turbo MPFI engine) anf to the MAF (it was damaged). But no real bad errors Nonetheless, it was not really a pleasure to drive with that improper ECU: That power gap from about 2500 to 4000 RPM is really awful! It's OK if you just have to drive that car from one point to another once (e.g. to just tansfer the car), but it isn't really a solution for daily drive! Better repair that damaged ECU! Link to comment Share on other sites More sharing options...
zukiru Posted August 25, 2008 Share Posted August 25, 2008 no mine's fine the question was more for curiosity's sake! the bad power band is likely caused by the difference in igniton timing and lack of boost... which means there is a difference in the ecus... even thought people have said they are the same (including chiltons) Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 25, 2008 Share Posted August 25, 2008 They can't be the same as the turbo's use a knock control system for ignition timing, and the plain MPFI's do not. Although very early turbo systems (85/86) might share a very similar ECU to the 85 2WD GL MPFI as I think the knock control system is not part of the ECU on the early turbo's. GD Link to comment Share on other sites More sharing options...
stickedy Posted August 25, 2008 Author Share Posted August 25, 2008 I had examined both versions and in fact the ECUs are identical, but the Turbo one has a very huge additional PCB which is supposed to be the knock control (it has a very primitive layout). This PCB is just pluged to the main PCB and could be changed or removed if needed or wanted. Nonetheless, the knock control doesn't cause the difference power band since it makes no difference if it's connected or not (I tried that for curiosity ) So, the difference should be made in software with different programs in the EPROM(s) of the main PCB. So, if you copy the EPROMs (e.g. to empty ones) and change them, you should be able to interchange the ECUs as well without further trouble. Link to comment Share on other sites More sharing options...
zukiru Posted August 25, 2008 Share Posted August 25, 2008 They can't be the same as the turbo's use a knock control system for ignition timing, and the plain MPFI's do not. Although very early turbo systems (85/86) might share a very similar ECU to the 85 2WD GL MPFI as I think the knock control system is not part of the ECU on the early turbo's. GD that makes sense.. thank you! al my reading/research has been into 85/86 model years on XTs cause those are what I have! (stickedy, are you saying you could reprogram these?) Link to comment Share on other sites More sharing options...
stickedy Posted August 25, 2008 Author Share Posted August 25, 2008 stickedy, are you saying you could reprogram these? No! I (or anybody else who has access to an EPROM writer) could copy the different EPROMs to make them fitting to the different engines. The ECUs are identical, the only difference (besides the knock control which is in fact optional) must be the software in the EPROMs. So if you copy/change the EPROMs, you could fully interchange the ECUs. But does this make sense at all? Onyl if you have a really non-repairable ECU and want to use a non-fitting one instead... Reprogramming is a different story. This is for sure possible, but you have to know more details of the software system. I guess it's rather simple compared to todays ECUs, but it's too difficult to understand if you don't do any in-deepth researches about it. And it's for sure beyond my skills. Link to comment Share on other sites More sharing options...
zukiru Posted August 26, 2008 Share Posted August 26, 2008 cool! Link to comment Share on other sites More sharing options...
Keiji22 Posted August 27, 2008 Share Posted August 27, 2008 The 87+ ecu doesnt have a boost sensor like the previous 84-86 models did. I have a boost sensor on my 89 RX... Turbo light comes on when there is positive PSI. :-\ Link to comment Share on other sites More sharing options...
stickedy Posted August 27, 2008 Author Share Posted August 27, 2008 That's not connected with the ECU afaik Link to comment Share on other sites More sharing options...
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