there is no spark on the coil for cylinder 2, a different coil and still no spark, I found that with the red wire to the coil (engine harness side) disconnected there is no change in the spark situation, appearing to me that the red wire is dead to where it gets its voltage or pulse. On my Forester with the same engine (2.5 DOHC) the three wires from the harness to the coil pack, the yellow wire is 12 volts, and the blue wire and red wire are about 9 volts each, on the Legacy there is no voltage on the blue or red wire. Anyone have a clue on this or a wiring diagram? Really appreciate any help...thanks

Here is link to fsm

http://www.main.experiencetherave.com/subaru_manual_scans/1997_Legacy_FSM/

 

O.

Should be similar to this. There could be a bad transistor in the ignitor, that does happen from time to time.

 

thanks for that, cannot find a wiring diagram after extracting the folders, should it be there?

porcupine, that was the wiring diagram I was looking for, do you know the location of the ignitor, thanks again

On that year, it should be on the firewall, sort of near the brake booster. I might have a pic of it on my '96....let me check.

Ah here we are, how's this?

 

I've got an ignitor setting here beside me somewhere known good.

 

If you're interested PM me.

Also, you probably figured this out already, but if you have no spark on cylinder 2 you won't have a spark on cylinder 1 either.

 

3 - 4

1 - 2

 

It seems I remember an Endwrench article saying something about on a few years around '96, they had seen one of the wires, maybe that pin 15 in the diagram, backed out of the connector.

hmmm, not in the same place on a 97, looked around and nothing yet, they didn't move it to in the drivers area, did they? I'll keep lookin, really appreciate all your help

I think I found it, under the big air collector, (actually right where your pic shows...duh) hidden by the air horn on the collector there, about the size of a pack of matches, maybe a little bigger, I was looking for something larger, I'm out there with a flashlight so I can get it in the morning, do you think one off a 98 Forester is the same for testing and temporary usage

Glad you found it. If the connector fits it might work for testing. It's a pretty simple device so probably Subaru used it for lots of models/years.

In looking at the schematic it seems to me you would lose not one but two cylinders, in my case the red wire from the ignitor to the coil made no difference in the skipping engine when I disconnected it, that left the blue wire only, so am I correct in guessing that I was running on cylinders 3 and 4 only! my poor baby, I did 45 miles of interstate driving in that condition today, I think I'll treat her to an oil change with Royal Purple!

I believe it will work. Both are even 2.5 DOHC's

 

Here in the rustbelt the screws can be tough. Often I believe I remove the plate it bolts to - but it's been a while.

The drawing that Porcupine73 so nicely provided shows that the ignitor provides the switched ground connection for the coil windings to make spark happen. When the ignitor is turned off the red and blue wires going to the coil should show a voltage near battery voltage like you saw on the Forester. (I assume you made the voltage readings on both vehicles while the ignition was turned on and the engine not running.) If you can find connector F25 in the drawing, disconnect it and then check the voltage on the red and blue wires again. If they are now near battery voltage then the ignitor may be shorted. One thing I don't understand though is how both sides showed a low voltage and yet one side still works.

 

EDIT:

I just noticed that pin 8 on F25 ties voltage to the coil. If you disconnect that connector you will need to tie pin 8 together in order to complete the circuit.

Edited November 7, 201114 yr by Cougar

Cougar, I did some measurements, as you look at the great schematic you would expect a voltage on pins 1 and 2 provided the transistors in the ECU are off, and that's what I got, but only once, after that no voltage on those pins, even turning off and on again, oh well, so I moved on, pins 5 and 6 naturally had nearly battery voltage because the coils are good and are receiving good voltage on pin 2 of the coil pack, so all is well there. Here I took the ignitor and found that I had about 65 kohms from pins 2 to 3 so my base to collector is good on the lower transistor in the ignitor, and those were my two running cylinders, 3 and 4, now to move on and check resistance from pin 1 to pin 3, the upper transistor responsible for cylinders 1 and 2, my non firing duo, that's where I found an open between the base and collector, even turning my leads around, there is I assume a burnt out diode in the base to collector junction. I took the ignitor from my 98 Forester and put it in and it runs on all four now. I am still puzzled though because I don't know what makes the coils fire, with 12 volts supplied to the primary I grounded the secondary and opened it rapidly, no spark! Not even a hint, I do this with an old conventional coil used for points and I will get bright blue spark on the plug (using a condensor aka capacitor). So I don't know how common ignitor failures are, but mark me down for one, I absolutely could not have fixed it without this forum!

Very good testing Jim. It appears you are well versed in electronic testing and ignitor failures are fairly common. It would seem that grounding the coil should produce a spark. Did you have both plugs connected to the coil and the plug bodies making contact to a good ground when you did the test?

no, I only did one plug at a time, it was grounded, just for my curiosity I'm gonna do two plugs, the newer coils like in the Subaru have their secondary coil completely isolated, as shown in the pic, the older singular Bosch, Lucas type coils you get ohmage (9 Kohms) from the primary to the secondary

You are correct about the secondary being isolated from ground but as you know in order for the circuit to work it has to make a complete a loop through the secondary windings. Starting at one of the secondary leads it ties to a plug, then passes through the electrodes of the plug which has the threaded end bonded to the engine ground. The path then ties to the other plugs grounded electrode, then through the plug gap, and then back to the other secondary wire for a complete loop. Sparks should fly (not literally) if you do that.

Edited November 8, 201114 yr by Cougar

Cougar, yep, real hot double spark on my test setup, you were right on, makes sense, but now for the kicker, I got the Legacy running with the ignitor from the Forester, got a used ignitor for fifteen bucks right here in town so I just put it on the Forester, it won't start......hmmm, no changes except the ignitor, coil has voltage, both wires to ignitor have voltage, so I figure the ignitor I got must be bad, I put it on the Legacy and it starts right up! Now I'm flippin out, what gives, the Forester will not start with it's original ignitor, when I turn the key to start it I get one spark from the coil on cylinders 1 and 2, (using a timing light, also a test plug on the end of the plug wire grounded) then no spark as it cranks, the plugs for cylinders 3 and 4 look ok and are sparking, but apparently not enough to keep it running, it seems like the ignitor isn't receiving pulses from the ECU, I'm baffled!