DTL

Thanks Porcupine. I printed that schematic a couple weeks ago and have it almost committed to memory! the ignitor is getting a bad signal for the 3/4 coil. Either, the sensors is giving the ECU bad info, or, .... nothing AFAIK (new acronym for me). I have pretty much gave up on the idea that supernatural forces intervene in between the time I test the connector and the time i plug it in. I am guessing maybe bad sensor or sensor conections, I just wish I knew a touch more about how the ECU processes the cam and crank sensor info, allso a confirmation that those are the only sensors that would have an effect on spark generation. Bill

Hmm, I will have to re-scope that. I counted roughly 12 more or less equal and evenly spaced pulses in 2 sec. They could have been pulse groups, I will recheck with a shorter time base. when normally starting about how fast does the engine rotate? 1 rev per 1 or 1 seconds?

Yes, Crankshaft sensor output was very close to that. As far as the ECU output goes. When I scoped the first ECU got what I thought was a normal output for 1/2 coil/ channel. The other one was insync instead of off set in time, it was less than .7 volts .... I think I looked at it loaded to the ignitor. I captured 2 channel 5 sec sample with my scope but the humidity started to make my scope act flakey, dropping out a channel w/o me touching the scope! so, I got flustered an brought it make onto the house! But the "new" ECU i bought 2 days ago acted roughly the same: 1/2 firing , 3/4 not....- my DMM jumped around 0 to 3+ volts for the 1/2 out put, the 3/4 output averaged under a volt. Maybe I will take my scope out again later today. What is the chance that 2 ECUs could have the same problem....small I would say, thats why I focused on the signal paths. but they check out ok, isolated from each other and continuous from connector to connector. ...its getting nuts, maybe one connector contact is bending away when you push it in.... I will try giving them a twist bend a bit later. I suppose I need to make sure the signal paths for the sensors are continuous. <b>I would like to see a flowchart describing the how the ECU uses the sensors.</b> Thanks porcupine

I am continueing this saga over at thread: Black comedy of errors:ECU/sensor problem Would love to hear from experienced Subaru electronics people. HAnk? OB?! Bill

Hi Cougar Yes. As I wrote in my post: "I am getting spark from the coil for #1/#2, but not #3/#4. The ignitor is not switching. I looked at the old ECU output by dragging my Digital storage scope out of the basement (something I will not do unless I am desperate). The ECU signal seemed probably ok for the 1/2 plugs but there was a much smaller signal for the 3/4 plugs AND it was IN SYNC with the 1/2 pair. I figured I found my problem, bad ECU and this new one would fix the problem. I figured I was seeing some crosstalk through the ignitor that is not enough to switch it. In fact I measured a base-emmiter voltage drop from either ignitor input to the both ignitor outputs, base 1 to emitter 1 and base 2 to emitter 2 were both like .7 volts-.8 volts , base 1 to emitter 2 and base 2 to emmiter 1 was almost double that. <b>This is true on both the ignitors I have so, I guess it is part of the desgn, and the ignitors are both good.. am I wrong?</b>" I looked at pins 9 and 10 at the ignitor. My question is really this: Under what conditions will the ECU only fire the 1/2 coil? ( I forget whether that is pin 9 or 10). There was a new timing belt put into this car about 2 months before it rolled over and played dead. Can a 10 thumbed mechanic screw up the cam sensor enough to do that? As far as what my scope saw, the crank sensor signal was noisier and funkier. Also, are the crank and cam sensors the only ones that will stop the ecu from firing?... I think I need the wisdom of a SubaGuru here.

replaced coil pack .... about .8 ohms primary for both about 15k secondary for both.

Hi all, This is a continuation of my previous thread about my 2.2 legacy burning xistors/ignitors. What a disaster, I have replaced the ECU twice, first time, it was not the ecu, it was the computer for the AWD LOL... I took a ride yesterday and got the right ECU from a junkyard in queens, plugged it in and .... no start. I am getting spark from the coil for #1/#2, but not #3/#4. The ignitor is not switching. I looked at the old ECU output by dragging my Digital storage scope out of the basement (something I will not do unless I am desperate). The ECU signal seemed probably ok for the 1/2 plugs but there was a much smaller signal for the 3/4 plugs AND it was IN SYNC with the 1/2 pair. I figured I found my problem, bad ECU and this new one would fix the problem. I figured I was seeing some crosstalk through the ignitor that is not enough to switch it. In fact I measured a base-emmiter voltage drop from either ignitor input to the both ignitor outputs, base 1 to emitter 1 and base 2 to emitter 2 were both like .7 volts-.8 volts , base 1 to emitter 2 and base 2 to emmiter 1 was almost double that. <b>This is true on both the ignitors I have so, I guess it is part of the desgn, and the ignitors are both good.. am I wrong?</b> Anyway, I used just my DMM today when it did not start and found still only a funky low voltage change for the 3/4 output signal. Made me think the connector cable for 3/4 must be open and I am looking at a floating voltage. after MUCH screwing around testing the cable andplaying with the connector while hanging uncomfortably nearly upside down, it seems all that every thing is good. Yesterday I also took the liberty of stipping some wire off the cam and crank sensor to get a scope peak at what they were doing and much to my dismay, they seems to be producing good signals: at cranking sppeed the CAM sensor put out about 12 AC pulses in 2 seconds.from .5 to 1 volt. The crank sensor put out groups of AC pulses in a roughly sinusoidal envelope varying between roughly .5 volt to 2 volts, from what I remember. These pulses were spaced roughly 20 to 30 msec in groups of 3, repeating roughly every 160 msec, they did seem a bit noisier than the cam sensor.. ?????????????????? I am at a loss, all I can think is that one of the sensors is screwing things up for the ECU, there is no chance both ECUs would fail in the same way.(?)! I am getting a knock sensor error...will that do it? the knock sesor is reading only 1/10 ohms as it should (5.7k). This new ECU is reporting a TPS error too, is that possibly left over from the previous vehicle, I was not getting that with the old ECU? I couldn't clear the errorcodes for some reason, did something wrong I guess. help, this is driving me up a tree. .

BTW the Ignitor gets ground through one wire in the ECU cable. It checked out... but i will recheck for intermittant problems. it will be a while before i get my hands on another ECU, so, I have some to mull it all over.

That is a thought... the ECM signal that didn't fire stayed high and noisier than the other, like maybe it was floating. It did sag a tad as I cranked the motor. Somewhere I have the info on how to read the error codes. I would be surprised if a bad sensor condition would allow for the ignitor to fry. I guess I will cruise on over to car-part.com and see if thy can help me. Been a rough day: the replacement fwrought iron style fence we were getting from fencedepot.com finally got here from china after almost 9 months of waiting. The first one that arrived last fall was supposed to be coated with superduper high tech paint and be guaranteed for 10 years against corrosion. It was rusting thru when it arrived. We complained and they were to ship us a full replacement at no charge. unfortunately, they sent us the WRONG model....then this thing....and as if to add insult to injury, I slipped on a banana peel while walking the dog... caught myself though... maybe there IS hope.

Ok, this is starting to get ugly. I sent $235.00 to http://www.ecmoutlet.com/ AKA safetyairbags et al and spoke to a mild mannered, smoothe talking SOB probably from Dallas. Their phone # is 866-663-0801 I have not recieve my ECU that was to ship Fri., They do not answer phones. They have not responded to requests from me or their credit card handling company 2co for a tracking #. A yahoo search http://search.yahoo.com/search?ei=utf-8&fr=slv8-msgr&p=866-663-0801 found a reference to them which google did not, Complaining that they cashed someones check, never sent the requested part, and did not answer phones. Had I found this ref, i woud not have ordered anything from them. (maybe they never answer calls from folks they already have taken advantage of maybe someone here could try their phone # and see if they pick up. Originally they wanted to do an over the phone bank draft/check, when I told then I don't do that they they can't take out of state credit cards????? anyone ever hear of that?) I checked them out with the BBB and there were some issues, but not nearly as many as another company( see my above post)... anyway, I have not been able to reach them by phone and never received any tracking #. I called the creditcard processing service they used: 2Checkout.com, Inc. (2CO) http://www.2checkout.com/community/ I am about to call these folks as well as Visa and see what our options are. 2CO says they will send another email to this company and if there is no response in 24 hours, I can begin the complaint process. They had a different phone # for these guys (817-704-0148) which turns out to be a voice mailbox. I left a message ... but, I doubt I will hear from this guy. Anyone else you folks know get screwed like this before purchasing online? This is my first, and I have bought many things over the years. Suggestions on what to do would be appreciated. DTL

I ordered it from the remanufacturer fri, should be here in a day or 2 I need it now, i need it to work, so I spent the money, lets hope it is worth it.

OK, I am buying the ECM from an outfit called strangely enough ECM, they also have an airbag business: http://ecmoutlet.com/index.html another $235.00 , but these guys seem to know what they are talking about. They say The software for the ECM is dependendent on the Vehicle VIN and needs to be reflashed. My guess it that the hardware is somewhat generic and the ECU # specifies the flash version. I got a quote for $55.00 from an outfit in Littleton Colorado but, after checking the BBB with there phone # turns out they are not the most reputable group that ever put up a shingle on the internet or anywhere. http://search.bbb.org/Results.aspx?ph=800-944-3215 The other guys were not nearly as bad in there BBB report. I confronted them with the BBB info and the guy said basically that they do hundreds of orders and there are always problems, many times it is customers who don't know what they are doing or, are less than reputable themselves. http://search.detroit.bbb.org/nis/newsearch2.asp?ID=1&ComID=0332000053001171 Then I get an email from the Littleton CO outfit, to whom I sent a link to their BBB record. The guy says that it is under new ownership as of May of this year.... He sounded even a bit embarrassed..... so maybe these guys are worth giving a chance. I went with the $235 ECM anyway, I just don't have time to screw around anymore. I will post again when I install it... hopefully it will all work. Bill

Alrighty then, Dug out my scope from its comf niche and found one output pulsing low for roughly 50 ms every 200ms or so, the other output stayed high and a bit noisier. There are a few places on the web that sells the ECU's. This one: http://www.ecudirect.com/finditfast/finalcombo_yearmakemodel.asp?vmake=SUBARU&vmodel=LEGACY&vyear=1991&type1= sell new ($500) as well as remanufactured($300). But neither they or a couple other companies have exactly my ECU: #31711 AA911. Soooooooooooo What to do? I can get mine repaired I think.... Not sure that the turn around time will be all that quick. I was wondering how important a few digits would be for my model Which is : 1991 Legacy LS 4wd ABS the VIN is 4S4BJ65C2M7900094. I think the car is worth maybe 1k-$1200 here on long island where cars are in high demand. It ran great until it died. $300 more would be about the max I would want to put in it... I would prefer to get away cheaper than that. Any of you have any suggestions for me at this point? What are the limitations as far as using different numbered ECUs? I gueass they are programmed to the specs of the of the sensors and transducers used in this specific model. I was wondering if another LS Legacy's ECU might work well enough??? or can another model be flashed/programmed to work with mine? I took the cover off the ECU, I was wodering how hard it would be to isolate the bad chip/component(s) and get replacement parts. I have done a little surface mount soldering, but not for years, it would give me an excuse to buy a decent surface mount soldering iron on ebay! Hankosolder? Thanks everyone Bill

was replaced ... thats what I thought until I remembered it it died a few months before it really died, and my wife had the work done.

Ok, Thanks. Y'know, when I put in the first xistor, I thought I smelled the smell of burning electronics pretty soon after I turned the key. I cranked it for maybe 30 sec before I gave up. I am now thinking it will be a bad ECU. If I use a DMM to read the ignitor control signals i was hoping I could determine quickly if it is bad by dc averaging somehow. I not sure if my other meter can do that. Can I put a parallel RC with a bit longer time constant than the expected pulse, ground one side and see what each output charges charges it up to after a few cranks.... (What pulse width should I expect? ) or discharges to... does it goes low ? geeze, a bad/intermittant/floating connector could do that. seems like it would be a bad design if it goes low to fire a spark. if ECU lost power for a bit it would fry the ignitor...I would HATE to fry another ignitor....can a bad key switch do that for me? too many things to think about ;-] Thanks for all the help.

I have a little electronics background... enough to get me in trouble...lol The ignitor and coil pack new wires are installed.... but somehow dropped a wrench on top of my meter lcd screen which now displays some chineese dialect in broken-alphanumeric. It is getting dark, tomorrow i will find my other meter and bring my digital scope outside and have a look at the control signal waveforms. Any idea as to how long a pulse would be toooo long? Well, only one side of the ignitor burned so, if something is wrong one will be much longer than the other. I was SOOOO tempted to try and start it up. But, I would rather not have to buy both the ECU computer and another ignitor (how much do the junkyards get for these?). BTW the F27 ground lug is where? under dash? the scan is hard to read but looks like it is connecting to terminals 7 & 8 on ECU I hate working under the dash, I practically need to hang upside down to do anything and/or see anything. http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/ignitionsystem.jpg I am guessing that the ignitor heatsink is not part of the circut. Thanks for the reply, I was afraid I would be going this one alone! Bill

OOOOOOOOK, I bought a used coil and ignitor from a junkie errrr junkyard salvage place. http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/ignitionsystem.jpg Gives a useful schematic, but, It looks like 2 spark plugs are on the same secondary with chasis ground ( or engine block) as a center tap(????????). This implies to me that one of the spark plugs on each side is a cathode and one is an anode. and that each time the spark has to jump both spark gaps to complete the secondary circut. I can see how this could fry my ignitor if the wiring from the ignitor to the coil gets exposed to the secondary. Could someone confirm this?, before i hook it all up i wanna makesure there will be no more expensive problems. I am going to beef up the insulation between the coil wiring and the motor block, any other suggestions will be appreciated. :burnout:

Yes. The computer seems to send logic 0's alternately to the ignitor's 2 inputs, the outputs of which seem to provide a path to ground for the +12v at the coil pack center tap alternately through the 2 primary coils. I will recheck the primary ohms, but my guess is that a HV short might not show up with any ohms test. I thought I checked for bad grounding and found everthing ok I would expect some circuitry like a flyback diode internal to the ignitor to catch any primary HV... I will recheck it all later today. I was hoping for a confirmation of my suspicions from one of you techies who might have come accross this in the past. I put in a parts requst to Quality Auto Parts internet parts locator who claim to have what I need for $68.00 plus shipping. I would prefer to buy from someone local... has any of you folks had any troubles with the parts locators, this one has a 251 area code, I am not sure where that is...

Hi All, I posted this somewhere else because I couldn't figure out how to start a new thread... I think I got it now.... I Have a 91 Subaru Lagacy wagon w/ AWD, ABS, automatic transmission, 2.2 litre engine sitting in my driveway waiting for me to fix it. It died 2 years ago the morning after a long trip. My wife said it was running rough towards the end of the trip in local traffic. The next morning, it started for a second, then stalled and has not started since. it has 180k of mostly Highway miles and was running well. The timing chain was replaced a few months before it's demise. I checked compression which seemed good. Turned out that the Ignition transistor was not firing one side of the spark coil. For $50. I got a good used xistor, popped it in and cranked it. No start. The new trasistor got immediately toasted. I have been staring at this Subaru for the last 9 months wondering if it is worth trying to replace the coil and the Xistor (perhaps the computer too?) The Coil reads about an ohm from the center tap to each of the lead ends and infinity to the spark plug leads. I am GUESSING that HV spark is leaking back to the xistor somehow. Any thoughts on this? I live on long Island and would consider selling this vehicle for a few hundred bucks to someone who wants to fix it or use it for a parts car. The ABS system looked shiny as if it was replaced not long before we bought the car and put our 20k miles on it. I have to clear the driveway within a couple of weeks, but, this was such a great car, I hate to sell it for scrap.