Steve W. Posted June 6, 2013 Share Posted June 6, 2013 Hi. Guys. Well, here I am with the same frustration as so many before me. I've spent the last few days battling with the wiring, and last evening just before I left the shop, I had it fired and almost running. I went in the house with a big ol' grin on my face, thinkin' I'd work the wrinkles out this morn. But after wasting the whole day, I'm in worse shape than last nite. I have the ECU layin' on the windshield, with the loose loom draped over the o/s mirror, (as per Chucx advice) and my constant power source strait form the bat. with an inline fuse. When I started this morn. I found that fuse blown, a 10amp, I tried a 15 which it blew instantly, so I isolated it down to the coil, which seems to check out ok, but the second I plug it in it smokes the fuse. I traced it all out, and can't find anything that could have changed overnite, I tried another coil with no gain. If I still had hair on top, I'd be pullin' it out, so I stopped , and went to work on the exhaust and other stuff just to calm down and not set the whole thing on fire. I've searched recent threads till I'm brain dead, before I bothered you guys. I'm hopin' I didn't smoke the ECU or something else expensive. Ideas? Thanks folks, Steve. Link to comment Share on other sites More sharing options...
Steve W. Posted June 10, 2013 Author Share Posted June 10, 2013 Hi. folks, I'm back. I've calmed a bit and haven't burned it down yet. I keep goin' back over the loom thinking I should be able to find the problem, but so far to no avail. A little more info., it's my daily driver, an 88 GL10T wagon, and I've got about a million hours in it. (More or less.) EA D/R 5 spd., 3:90 r. diff. w/ posi. I did about a three inch lift a few years ago, and dropped all the sub frames an inch and a half. Five lug swap, w/ XT6 back plates & rotors, 240 SX calip's & e-brakes. Late model Legacy front susp. w/ dual pot calip's & early WRX rotors. New KYBs all around. Manual fuel pres. & boost controllers. Water to air I/C. TDO 4 w/ my own 3" bell mouth dn. pipe, 21/2" back to a Flowmaster. (Loud). My swap of choice is a 93 EJ 22T, that went together nicely. This wiring issue has bro't me to a stand still. I've been at this wrenchin' business for a lot of years, and hate to admit defeat, so still hopin' somebody will come to my rescue. My wife told me some time ago to buy a loom already stripped & wrapped, but I felt this would offer me more insight into this engine management syst., and I'm sure it will once I get past this stumbling block. So, I'll pay thanks forward to any & all helpers out there. S. Link to comment Share on other sites More sharing options...
presslab Posted June 10, 2013 Share Posted June 10, 2013 If the ignitor or the ECU output is shorted it could blow the fuse. The coil is only designed to have power applied for just a moment to fire the spark plug. It power is applied continuously it will draw a lot of current. Try to unplug the ignitor or ECU and see if it blows. Link to comment Share on other sites More sharing options...
Steve W. Posted June 13, 2013 Author Share Posted June 13, 2013 Thanks Presslab. Well, I went over the whole thing again, reworked some of the power supplies and got past the fuse blowing thing. I now have one of the sweetest runnin' two cylinder Subys around. Actually running on the back two cylinders, no spark to the front two. I checked all the sensors, and replaced the coil and igniter. Engine loom perhaps? I don't know, I'm pretty bummed, If I didn't need the car so badly, I'd stop now and go on to other jobs. Frustratedly, thanks. S. Link to comment Share on other sites More sharing options...
ivans imports Posted June 13, 2013 Share Posted June 13, 2013 Have done many 2.2 harness cutdowns I know all the wire coulors with my eyes closed the 2.2 t harness was harder than a regular 2.2 harness is easy to miss somthing or conect the wrong wires mabee damaged your ecu Link to comment Share on other sites More sharing options...
Legacy777 Posted June 13, 2013 Share Posted June 13, 2013 Try swapping the pins between the front and rear on the coil pack and see if the front two cylinders start firing or not. That will confirm whether the coil is working properly or not. Link to comment Share on other sites More sharing options...
presslab Posted June 13, 2013 Share Posted June 13, 2013 It's possible that a transistor in the ECU was fried. The voltage from the ECU to the ignitor isn't that much, so a test light won't work, but you could see it on a scope. You might be able to measure it on a frequency counting multimeter. Link to comment Share on other sites More sharing options...
Gloyale Posted June 13, 2013 Share Posted June 13, 2013 (edited) It's possible that a transistor in the ECU was fried. The voltage from the ECU to the ignitor isn't that much, so a test light won't work, but you could see it on a scope. You might be able to measure it on a frequency counting multimeter. Try another Transistor. Just for double check test the signal wire for the front 2 cyl.....It's either the red/green(R/G) or the blue(L) one in that connector....whichever is on the "Front" will be that wire. A test light between that wire and the Yellow/red(Y/R) wire in the center while running should pulse. Between the engine harness and the transistor/ignitor those wires run throught the SMJ. Red/green through M2 of SMJ Blue thorugh L2 of SMJ Edited June 13, 2013 by Gloyale Link to comment Share on other sites More sharing options...
presslab Posted June 13, 2013 Share Posted June 13, 2013 Yeah a test light between the ignitor and the coil should pulse. You said you swapped the ignitor so I guess we can assume it's good. I believe this is the schematic: Link to comment Share on other sites More sharing options...
Gloyale Posted June 13, 2013 Share Posted June 13, 2013 Diagrahm is correct, but doesn't show the SMJ If the OP cut out his SMJ I'll bet that the problem is there. Link to comment Share on other sites More sharing options...
Steve W. Posted June 13, 2013 Author Share Posted June 13, 2013 Cool. Thanks guys. I'll run with this new info. first thing in the morn. and see what I can figure out. Hopin' I didn't cook the ECU, don't have a back up. Gotta' get this thing going, it's my only work vehicle. Much thanks again. S. Link to comment Share on other sites More sharing options...
Steve W. Posted June 14, 2013 Author Share Posted June 14, 2013 Hi. all. Well I checked the coil wire from ignitor to 1 & 2 , no pulse. Nice clear pulse from 3 & 4. Also, #1 & 2 side coil gets hot in a hurry, seems both wires into 1 & 2 appear to be hot. Something grounded that shouldn't be? I'm gonna' wait for more guidence so as not to create more damage. Thanks everyone. S. Link to comment Share on other sites More sharing options...
Steve W. Posted June 14, 2013 Author Share Posted June 14, 2013 Sorry, let me correct that statement. Probing the two wires going into #1 & 2 coil, the test lite stays on brite, as if the trigger wire goes to ground. Am I making it clear at all? S. Link to comment Share on other sites More sharing options...
Gloyale Posted June 14, 2013 Share Posted June 14, 2013 Yup sounds like it. That would explain the hot coil and blown fuses Disconnect the, Ignitor and the coil plug. Then test the signal wire (Blue one I believe) for 1+2 for continuity end to end from the ignitor to the coil, and then for continuity to ground, and finally for any continuity to any other wires. If that checks out (~0 ohms end to end, Infintie resitance to ground or any other wires) then check the circuit from the ECU to the Ignitor. That would be the Green/white wire from pin 9 at the ECU to pin 2 of the ignitor plug. Just to clarify, do you still have the SMJ or did you cut/splice it out? Link to comment Share on other sites More sharing options...
Steve W. Posted June 14, 2013 Author Share Posted June 14, 2013 Hi. No, cut out the SMJ. I'm gonna' do the continuity test rite now. Cross my fingers & my legs that it's something as simple as a bare wire short or like that. Thanks, S. Link to comment Share on other sites More sharing options...
Gloyale Posted June 14, 2013 Share Posted June 14, 2013 (edited) Make sure you have ground at pins A11 and A22 at the ECU. And of course to the D15 pin shown in the above diagrahm. Missing ground on that circuit could make it impossible for ECU to make the pulse. You'll figure it out I'm sure. Your "halfway" there lol Edited June 14, 2013 by Gloyale Link to comment Share on other sites More sharing options...
Steve W. Posted June 14, 2013 Author Share Posted June 14, 2013 Well, bad news I think. Good continuity from the coil connector to the ignitor, and from the ig. to the ECU connector, so -- bad ECU? I'd have thot if a transistor failed, it would fail to open not to grnd. Checked A11 and 22, their tied into my bunch ground. D15 comes out of the ECU and splits to two, both grounding back thru the engine loom, right? So, whataya think, am I lookin' for an ECU? Could I get by with a non turbo unit, since I'm not needing the boost control, waste gate, etc.? I just pulled some parts off of a 93 normally asperated at the wreckers yesterday. Discouraged, S. Link to comment Share on other sites More sharing options...
Crazyeights Posted June 15, 2013 Share Posted June 15, 2013 (edited) Well, bad news I think. Good continuity from the coil connector to the ignitor, and from the ig. to the ECU connector, so -- bad ECU? I'd have thot if a transistor failed, it would fail to open not to grnd. Checked A11 and 22, their tied into my bunch ground. D15 comes out of the ECU and splits to two, both grounding back thru the engine loom, right? So, whataya think, am I lookin' for an ECU? Could I get by with a non turbo unit, since I'm not needing the boost control, waste gate, etc.? I just pulled some parts off of a 93 normally asperated at the wreckers yesterday. Discouraged, S. As I recall the cam and crank sensor wiring are swapped on the Ej22 vs the Ej22T. It is important that both the engine harness and the ECU type/pin-out both match or at least that you take this in to consideration when preparing your harness or choosing your ECU. Edited June 15, 2013 by Crazyeights Link to comment Share on other sites More sharing options...
presslab Posted June 15, 2013 Share Posted June 15, 2013 The tuning for a turbo motor is completely different, regardless of how you control boost. It would not be safe to run a N/A ECU without tuning, which is an advanced subject. Transistors can fail shorted or open. For example the bond wires can open like a fuse or it could touch the wrong parts of the die. If you open the ECU you can follow the connector trace to the power transistor. It might be shared with other transistors in the same package. Often it will show visible damage like a darkened spot or a crater. Link to comment Share on other sites More sharing options...
Steve W. Posted June 15, 2013 Author Share Posted June 15, 2013 Thanks Guys. I guess there's nothing to lose in opening the case, Isn't the pc board epoxy dipped? We're gettin' out of my realm here, It isn't that I'm not open to learning, that's why I decided to strip the loom out myself. So, if you all are willing to put up with an old mans stammerings, I'll keep tryin'. Gonna' go pop the lid on this box, and see what I can see. Thanks again fella's. S. Link to comment Share on other sites More sharing options...
presslab Posted June 15, 2013 Share Posted June 15, 2013 Thinking about it more, the ECU is probably open and not shorted. With the ECU transistor open, the ignitor will be powered through the pull-up resistor inside the ECU, and therefore the coil will be on. Another test you can do is to temporarily short the ECU pin to ground. This should cause the plugs to fire. If so, then the ECU is not working. There are some parts in the ECU which are semi-custom and could be hard to find a replacement. But it's bad anyway, what do you have to lose? The PCB is "conformal" coated. It's like a thin clear plastic coating that can easily be melted off with a soldering iron. You're probably thinking of "potting" which is epoxy. Pop open the case and take a look. It would be a good idea to keep the static electricity low with a grounding strap on your wrist, or just touch some grounded metal every minute or so. A bright flashlight helps to shine through the board so you can follow the traces. Once you find something that might be it, get the part number off it and post it here. Link to comment Share on other sites More sharing options...
Steve W. Posted June 16, 2013 Author Share Posted June 16, 2013 So, I opened the case, got out my big magnifying glass/lamp and looked it over. Easy enough to trace out those pins over to where they go thru the pc board, on the other side they go to a coupla small black rectangles (transistors?) marked on top 27-23 and ID'd on the pc bd. as Z8 & Z9. Continuity was good up to them, beyond that I didn't know where to go. Nothing seems discolored or out of place. A guy over at Legacy Central says he's got a turbo ECU for $50 + shipping, so I have back up. On hold for a day or two I guess. I have a non-turbo ECU that I could rob parts out of if that would work. Lost again, S. Link to comment Share on other sites More sharing options...
presslab Posted June 16, 2013 Share Posted June 16, 2013 Can you post a photo of Z8 and Z9? Especially the markings. A single transistor has 3 leads, the reference designator "Z" is usually for a zener diode which has only 2 leads. You can often check a transistor with a multimeter's "diode check" function, most multimeters have this. Probe the transistor in all possible ways and record the voltages observed. Compare the "good" transistor voltages to the "bad" one. Link to comment Share on other sites More sharing options...
Gloyale Posted June 16, 2013 Share Posted June 16, 2013 The tuning for a turbo motor is completely different, regardless of how you control boost. It would not be safe to run a N/A ECU without tuning, which is an advanced subject. Transistors can fail shorted or open. For example the bond wires can open like a fuse or it could touch the wrong parts of the die. If you open the ECU you can follow the connector trace to the power transistor. It might be shared with other transistors in the same package. Often it will show visible damage like a darkened spot or a crater. I'm not sure here. There sare definately people who have run turbos with NA ECU's. Pretty sure Ivan has talked about doing that. The Crank and Cam sensor wires are reversed on Turbo/ Non-turbo ECU but otherwise all pins are the same. OCuld be useful for a tourbleshooting/temp solution until the Turbo ECU can be sroted out. Link to comment Share on other sites More sharing options...
presslab Posted June 16, 2013 Share Posted June 16, 2013 Pretty sure Ivan cooks a lot of pistons too. As I said, the timing and fuel mixture are substantially different, and it wouldn't be safe. Just compare any stock turbo map to a N/A map and you'll see. The only way to consider running a N/A ECU would be to unhook the wastegate lever completely to run the bare minimum boost. The EJ22T uses a silver Hitachi MAF so the only N/A ECUs that would be close are the 90-91 MT EJ22. The 93 ECU uses the green label JECS MAF. Link to comment Share on other sites More sharing options...
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