habib99 Posted June 19, 2005 Share Posted June 19, 2005 Decided to ask the most important question of all (rather than the rather long and complicated thread posted before which asked loads of questions -most of which I have worked out in the end with some help -thanks) Can anyone advise on wiring the ignition system on an engine using an ECU with a big number 3 on it (and it has only 3 plugs) -basically I have the ECU, the dizzy (4 wires: BW BY BR Y ), coil, knowck sensor in the engine. Please can anyone tell me how these items connect up? I have one wiring diagram that doesnt show the knock sensor anywhere (otherwise correct for the engine and ECU that I have) and another shows a knock control unit as a completely seperate part (seperate to the ECU and Disty/Ignitor but I dont have that part. please help -this is the final hurdle of a long race and I really really want to get this engine running! thanks Link to comment Share on other sites More sharing options...
NoahDL88 Posted June 19, 2005 Share Posted June 19, 2005 what engine, what vehicle? what years of the parts, what specifically is it not doing, spark fuel or crank? Link to comment Share on other sites More sharing options...
habib99 Posted June 19, 2005 Author Share Posted June 19, 2005 what engine, what vehicle? what years of the parts, what specifically is it not doing, spark fuel or crank? One of my big problems is that I dont know what year it is as its a lone engine -the original car is long gone (I never saw it!) but it is a 1.8 EA82T MPFI. But the fact that all the wiring on the engine and loom match a diagram has been a blessing but the disty bit doesnt -maybe I've just got the wrong disty? But then again the diagram doesnt have a disty on it at all -just a ignitor and coil, that's it. I have found another diagram that matches the disty (one of the engine control 1/4 page service manual diagrams) but that shows a knock snesor and control unit (seperate from the ECU) THe givaway for this engine is that the ECU only has 3 plugs -all the other MFPI Turbo diagrams I have seen are 4 plugs. I was hoping this would be enough to identify it! thanks for reading and helping if you can Link to comment Share on other sites More sharing options...
NoahDL88 Posted June 20, 2005 Share Posted June 20, 2005 Does the harness have room for 4 plugs? cause if it dosn't it could be the MPFI NA harness, as i believe the computer to be. Link to comment Share on other sites More sharing options...
Cougar Posted June 20, 2005 Share Posted June 20, 2005 It may be for an '88 model year. I have a manual for that one. I will be home on Friday and check it for you if you don't have an answer by then. Link to comment Share on other sites More sharing options...
MilesFox Posted June 20, 2005 Share Posted June 20, 2005 maybe you have the 85-86 ecu, this ecu runs with a mechanical disty that has 2 wires to the coil, and a harness that goes to the separate knock control unit. the disty you have and describe looks like the optical type, for 87 and up do you have the mass air flow sensor> is it a flapper5 or a hotwire? flapper for 85-86 and hotwire for 87+ between 85-86 and 87 up the intakes will be the same alkthough the plugs may be shaped differently. look on the bottom of theheads, if they are gen one and are original the motor will be 85-86. gen one has ea82 stamped on the bottom gen 2 heads will have ea82 with a line around it, 87 and 88 models gen 3 heads are 89 and up, ea82 has a box around it hope this helps Link to comment Share on other sites More sharing options...
habib99 Posted June 20, 2005 Author Share Posted June 20, 2005 maybe you have the 85-86 ecu, this ecu runs with a mechanical disty that has 2 wires to the coil, and a harness that goes to the separate knock control unit. the disty you have and describe looks like the optical type, for 87 and up do you have the mass air flow sensor> is it a flapper5 or a hotwire? flapper for 85-86 and hotwire for 87+ between 85-86 and 87 up the intakes will be the same alkthough the plugs may be shaped differently. look on the bottom of theheads, if they are gen one and are original the motor will be 85-86. gen one has ea82 stamped on the bottom gen 2 heads will have ea82 with a line around it, 87 and 88 models gen 3 heads are 89 and up, ea82 has a box around it hope this helps Thanks this is a help, MilesFox -you the man! & thanks for the offer Cougar funily enough it is an 1988 wiring diagram that seems to fit everything so far but it doesnt include the distributor or knock sensor on it!arararrgghh! ..then my heads are GEN ONE I have two distys to choose from -one has vacum advance mech unit and the other has a disc inside it with notches cut out at intervals (?optical device). The ECU is definately for MPFI EFI and has THREE plugs 34 wires in total. I guess that essentially my problem is that I cant figure out how to correctly wire up EITHER of the distys to the ECU and coil to ignite the engine properly, suppose I could just wire up the vacum advance model but it would miss the knock control and I dont really want to break my engine! I dont have the external knock control module and even if I did I wouldnt know where to attach it on the ECU or even if my ECU can run that unit/disty. every thing else is sorted out but this final bit has kind of got me stumped! any more ideas with this information? -I dont mind making things work by re-wiring/bypassing etc. This is all fairly temporary until I get MegaSquirt set up -then EDIS ignition will take over anyway Link to comment Share on other sites More sharing options...
john in KY Posted June 21, 2005 Share Posted June 21, 2005 The flapper AFM was only used on the 85 and 86 models. Since you have this AFM won't it be easier just to find an 85/86 intake, distributor and ECU? You could also go the other way, toss the flapper AFM and find an 87 or newer intake, AFM, distributor and ECU. You can't make an 87 or newer ECU work with the 85/86 stuff. You have either an 85 or 86 engine/intake/sensors. The AFM is also either an 85 or 86. This is good. But you don't know which year distributor and ECU you have. This is bad. Again, you just can't mix 85/86 stuff and 87 and newer stuff. A Subaru dealer or a wrecking yard should be able to tell you what year ECU you have. Probably could do the same with the distributor. Both have part numbers. Once you have all the parts either 85/86 or newer than you really need the FSM wiring diagram. A 87 or newer wiring diagram will do you no good if working with 85/86 components. Link to comment Share on other sites More sharing options...
habib99 Posted June 21, 2005 Author Share Posted June 21, 2005 Thanks for this info, Looks like I must have a mismatch of parts as people have said already! Anyone out there tell me what year(s) had the three plug ECU, if not I'll try a wreckers but not sure how much subaru specific knowledge they're going to have and dealers, hmmm they dont really want to know about these old motors anymore. thanks all, I'm not giving up on this one! Link to comment Share on other sites More sharing options...
Cougar Posted June 25, 2005 Share Posted June 25, 2005 My '88 manual shows that the SPFI ECU has 3 plugs and the MPFI has 4 plugs. Neither model matches the color of the disty wires you show. Link to comment Share on other sites More sharing options...
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