poconoracing

Rockauto.com

NGK Coil - $69.79 ea

Posting this in case anyone else comes across this problem

My 2010 GT - 134k miles would suddenly stall, like someone hit a kill switch. Completely randomly, with no consistency on the time run, temp, weather, etc.

No CEL, no other symptoms, car would crank but not fire. Come back it it later and it would sometimes fire right up.

Diagnostics verified crank signal, fuel injector pulse but NO spark at any of the 4 coils.

At the coil plug had power, ground but no control signal at any of the coils. Thinking the drivers in the ECM went bad, I went after the ECM behind the dash. I verified powers and the main grounds. I was just about to condemn the ECM when I noticed on the ignition wiring diagram the ECM has grounds that run through the Engine harness back to the grounds under the hood on the drivers side of the intake.

Turns out they run through PINS 34,35,36,37 and 40 of the large engine connector. They are the larger pins in a left to right row in the center of the plug. In my case #35 had been bent in slightly and was breaking contact intermittently. using a dental pick i bent it back into place and no issue since. No one has touched that plug in better than 2 years, really odd failure.

But nothing better than a cost free repair

Edited to add the wiring diagram from the FSM for the ignition.

ignition.pdf

Wouldn't they then get updated? The accessport manager phones home when you launch it.

It doesnt matter really anyway, doing some more poking around those are all for the 2010 GT. The WRX files are in a separate folder

Here is what I have. DM me if it'll help you

Two of the below are for a 2008 WRX. I'm not sure how you would tell them apart

**update, they are all for the 2010 GT - the wrx files are in a separate folder

You have a test light or a voltmeter?

Check for 12v at the big red wire. should be hot all the time

assuming it is, have someone get in and try to crank the car (clutch in, key turned to start) and check for 12v at the small terminal wire.

If you have 12v there with the key in crank and clutch in, replace the starter.

If you dont have 12V at the sense wire ... check the clutch switch and the starter relay

Mobil 1 5w40 Turbo Diesel Truck is a close equivalent to T6

You are looking for a synthetic diesel oil with API Rating CJ4

I'm in NE PA, similar temps to OP.

I've had moderate success with AMSoil Severe Gear 75w90. Better in first, still not perfect.

Car has been hard shifting in the cold since I bought it.

I thought the same thing but the good battery and the voltage on the positive input of the coil dropping to 10.7 during cranking is what led me there. The service manual said anything over 10v while cranking was fine. The only thing I can come up with is the aftermarket ignition coil on the car did not like the lower voltage. I could add a jump pack to the car when it was cold and it would start every time. I did voltage drop tests on all four wires from the coil, all the way to the ecm on the signal wires also. Additionally did voltage drop tests on the hot lead to the starter. All tested fine. That’s what led me to the starter having high current draw. I’m just glad it’s fixed.

Believe or not ... my forester appears to have had the same issue with the starter. Swapped it out a month ago with a new one from Autozone. Not one no start since.....

Thanks for sharing.

Agree talking to the dealer is worthwhile. If no luck there I woudl try to determined if the short is internal or external to the radio.

Disconnect the battery

Pull it out of the dash and disconnect it

Put the fuse back in and reconnect the battery

If the fuse blows with the radio disconnected the short is in the harness .... start with the connector and work your way toward the fuse panel. Look specifically at places where the harness comes in contact with the dash.

If the fuse doesn't blow, the short is very likely internal to the radio - replace it - junkyard or aftermarket

well i can give some input on WHY mine also gives a brake light but i havent gotten a fix for mine yet as i cannot figure it out.

 

I had the parking break engaged when i went to work on my brake pads (stupid i know) i didnt think it through and ripped off the rotor and basically all the tension broke the springs and i had to do a complete rebuild. seemed simple enough as i just took the other one apart and matched the good one. So ever since then ive always gotten a flashing brake light when ever i use the parking brake now. ive tried adjustments and checked everything multiple times. my only choice is to probably send it in to get repaired which is why sadly i dont have any cures. But i hope this might help you look into what might be an issue on hardware also. never know, you might have gotten a car from a home mechanic like myself who accidently messed up. it happens

FYI the issue you likely have is the parking brake calibration. After changing the parking brake pads you need to force the system to calibrate via SSM or a high end scan tool. Basically what it does is exercise the PB a few times to find when it’s on and when it’s off.

If you check with your local garages, I do believe the snap on verus has the functionality to make the car run the calibration. If not you’ll need access to Subaru Select monitor.

My son in law did the same thing and I had to fix it via SSM3

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How many miles are on your car? I have not replaced any front suspension parts so far besides the Koni/Eibach setup and wonder if anything will come up soon. I’m at around 106k.

 

 

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134k on it. front control arm bushings were shot so i needed t do some work anyway.

i went with the stock 13-14 setup because i live on a dirt road up a mountainside. i cant reasonably lower the car as much as i would like to.

the car handles well. much flatter in the corners. much less boaty/accord like.

downside is my stock springs were obviously pretty tired. the car is about 1/2 in higher all the way around.

only been a few days, we will see how she setttles in.

13-14 replacement KYB's and 13-14 springs. Also did Mevotech lower control arms w/ solid bushings.

After alignment, car handles well. definitely stiffer in the corners.

Only concern is the front wheel gap is a bit bigger than it was. hoping the springs settle some over the next couple weeks.

Bought a front wheel bearing .... cause the wheel it probably shouldn't move 1/2 an inch.....

Going to need to blue wrench tomorrow to convince those bolts to turn.

Oddly it did not make a sound, no groan, whine or any indication it was bad.

Glad you got it handled. You did the right thing .., patience works wonders.

Odds Re there was aluminum corrosion on the threads in the hole. Happens more often then you think in The bellhousing bolts and the head bolts.

A trick I’ve used is take one of the old headbolts and cut a grove down the threads with a cutoff wheel on each side, or three if you are ambitious. And use the cut bolt as a tap. The groove gives the material somewhere to go. Then same as you did, oil, turn it in until it starts to bind, back it out and clean off the grime. It would work in your situation as well. You could actually use the grooved bolt if you like, or replace it.

Lastly use a bunch of neversieze on the end of the bolt to coat the threads, and hopefully prevent a future problem.

I'm glad you found it. How did you diagnose it?

My Car has the original starter. Anything is possible, but a high enough amp draw to pull down the entire system on a functional starter engagement would be a new one to me.

Did you end up figuring this one out? Fighting something similar. Thanks

Not completely. I know what it is . Resistance in the signal wires between the ecu and the coil.

I haven’t had a chance to get back to it. I used deoxit on the engine plug and the coil plug. No change. There are only 3 plugs, the ecu, the engine connector and the coil connector. I’m going to have to trace the wires.

It’s definitely on that harness somewhere.

yes. it'll actually be easier. As long as the heads are still on the block.

Youll have turn each cylinder to TDC by hand, put the leakdown tester in and see what the loss is.

If you have never seen what i'm talking about, here you go.

Do a leak down test of each cylinder. Then you'll know if and where the compression is going. If you are losing it through the exhaust or intake valves you'll have to pop the heads off and see what's going on. if you losing it to the crankcase you are likely looking for a motor.

It could be a simple as a carboned valve seat, a dropped guide or a burnt valve. Still an involved repair, but not one that can't be done with some patience and a good machine shop.

Ok, 25 degrees and no spark

Broke out the oscilloscope - good waveform from the cam and crank sensors when cranking.

back probed on the the coil.

Pins 1 & 4 - 0-7.8V square wave

pins 2 & 3 - 12V and ground - less than 1 ohm resistance from ground to block

FSM says should be 0-10V min or swap the coil and ignitor assy

swapped it - nada

Son has to go to work - put the 450amps to it ..... fired right up on the new coil. GRRR

Perhaps we have some resistance somewhere between the ECM and pins 1&4 on the coil connector? I'll dig up the wiring diagram and start tracing

Back at it tomorrow after it sits overnight. Why cant this happen when its 70 degrees and sunny?

BY the way if any of you are looking for an inexpensive scope solution. Here is the one I'm using. Works well for $100

https://smile.amazon.com/SainSmart-Portable-Handheld-Digital-Oscilloscope/dp/B074QBQNB7/ref=pd_bxgy_2/135-5337730-2946353?_encoding=UTF8&pd_rd_i=B074QBQNB7&pd_rd_r=c25631bd-29a6-4a2f-9d3d-9b95d5065fb3&pd_rd_w=cRY32&pd_rd_wg=a3ryb&pf_rd_p=f325d01c-4658-4593-be83-3e12ca663f0e&pf_rd_r=Z2BKBKNAYR281DJ3CVZW&psc=1&refRID=Z2BKBKNAYR281DJ3CVZW

Love scannerdanner. Great diagnostic videos.

Yeah it cranks fine, sounds fine while cranking, it is firing the fuel injectors it simply has no spark. no spark signal at the coil from the ecm no spark signal at the pins on the ecm connector.

I thought I might have a driver going bad in the ECM, bad solder joint splitting in the cold, something like that, hence the used one, but it did exactly the same thing.

I have an RPM signal while cranking when looking at the live data.

For the cam it shows timing, not rpm. It had that weird -7 deg ignition timing when cranking when it didnt start, but with the 450amp starter hooked up it showed +15 deg of timing.

Swapping the cam sensor is more money and more PITA so before getting out the parts canon I wanted to see if someone here knew where the ECM derives its spark trigger.

So the No start reappeared like clockwork earlier this winter. Still sub 20 degrees or so and no spark. No CEL set or pending

I bought an ECM off ebay, and before you ask the car is pre immobilizer. Apparently 2008 was the changeover for the Forester, mine is an early 2008.

Swapped the ECM and ...... no spark. Note is firing the injectors. Powers and grounds to the ECM check out fine. Cleaned every underhood ground I could find. replaced the battery cables for good measure with OEM.

Got out the 450 amp starter .... and it fired right up on the used ECM

Only new thing I noticed - on the live data the timing read -7 deg when it won't spark and +15 degrees when its idling running.

Anyone know where that timing value comes from? this is a SOHC 2.5L NA motor. I would assume its a derived value from the cam/crank correlation? And what else would cause a no spark? knock sensor? air gap on the cam or crank sensor maybe? I know both are a magnetic field based sensor

What baffles me is why the 450amp starter fires it right up, and it starts perfectly for the rest of the day. Maybe the system voltage increase means a stronger magnetic field? It 100% has an RPM signal at the ECM when its not firing, so I'm looking more to the cam sensor.

So couple questions if anyone knows subaru timing logic:

Does the cam signal trigger the spark?

If I unplug the cam sensor will the ECM use a default strategy?

Same with the crank sensor?

This car is now my 17 year olds primary transportation, he can jump it but my fear is eventually it going to leave him sit and for my own sanity I'd like to track this issue down once and for all.

Step by step DX of the valve body on a 2013

If you are interested. at some point someone posted this tool on the forum for finding boost leaks.

https://smile.amazon.com/gp/product/B0825WNGP3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1