Weird Electrical Issue

[bradyhall]

Please watch the video I attached to see what is going on. 

I’ve been working for about 18 months to solve this electrical issue. The hard part of diagnosing it, is that it doesn’t ever throw any codes. When it dies while I’m going slow or just getting going from a stop the car will not start for some time. Power to all other part ms of car still works. When you turn the key to the start position after such an event nothing happens as in the situation of an extremely dead battery.

When driving, as you can see in the video, it will die and then kick right back on but you can hear an audible clicking noise. The engine cuts out and if you are going above about 15 mph it will turn back on as if nothing has happened. I’m thinking that something is causing a relay to trip which is cutting power to the ECM…truly a weird situation. 
My instinct says faulty relay somehweee or sensor that trips relay. A bad ECM would not be intermittent like this would it? Any help would be appreciated. Brand new battery. Not a single diagnostic code. 

 

 

[Yeszerd]

Not sure if this will help, but do you have access to a scan tool that can read all the modules on the car? a while back I was having a electrical issue on my car that would throw the car into limp mode. Mind you it did have one code I could read, which was a p0600. My basic scan tool wasn't able to retrieve the more sophisticated codes or data that a more expensive one could. Finally took the car to a local shop that had a more competent scan tool and showed a communication issue with my one my modules, swapped it out and been ace since. 

[Tehnation]

any pending codes? Does it happen at idle, if so I would just sit there and keep refreshing my codes for a pending code, cause your cel is flashing on. It should be stored as pending, do you have a obd tool? Wiggle some wires like the main engine harness connector to see if you get a response. 

Should your abs light be on or is that something else? 

Is the car a manual or automatic? If its a manual, it could be turning off, but being that its in gear it will force the car back on. Like popping the clutch to start a car with a dead battery. 

18 months and nothing? At that point if I were you I would just pay the 1 hour labor for at the dealership for diagnosing at this point! spend the 100-125 dollars and have a subaru tech put it through its paces, cause electrical problems downright suck and if you aren't a pro at diagnosing it will be a nightmare, which after 18 months I assume it is.  

On another note, have you you approached it from a temperature point of view, ie does it work fine when you 1st start the car, and then after driving it happens and then it won't start again after giving it time ie time to cool down? If thats the case it could indicate something like a sensor is getting hot and malfunctioning. I had an issue I was chasing for weeks, no code, car gets hot and would crank and not start, no codes. Turned out to be the crank position sensor, would just stop working when it got hot. So take note of whate else is going on when its happening. 

Or is it completely random?  

Does the car actually lose power or is it your cluster just going crazy? It doesn't seem like it stalled, it just looks like your gauges are just going crazy for a second. Do you feel it cutting off? 

[Max Capacity]

You can also find a local repair shop that can do the testing, it will be less $$$. Look for a old repair shop that has been in business for many years. Not sure where you live, but here in CT good repair shops are easy to find.

[bradyhall]

Hey thanks for all of the ideas. I have had several shops look it over, even a specialized tuner shop. The difficulty is that the problem is intermittent, (although it has gotten much worse in the last few months), and it doesn't throw any codes, even for a special scan tool. So, none of the shops could diagnose anything...

It does lose all power when it does it's thing, it looks like the dash is just wigging out but the engine actually cuts out. If you listen carefully you can hear the blowoff valve release boost when it clicks. The ABS light and traction control light come on when it does it, but then they go off after the engine shuts off and turns back on, but they don't always come on.

As far as temperature, I know that there is a connection to the operating temperature of the engine and the issue. It will never do it if the engine is cold, it only does it when warmed up. The first time it happened was sitting in a drive thru idling for about 10 mins. This is why I believe is has to do with a Sensor/Relay because it seems to reset after some time. I'll check the Crank position sensor.

I probably should have mentioned that my car is a 2007 SpecB with a Stage 2 Cobb Tune. Turbo back cat-less exhaust. 

Any ideas as to any other Relays/Sensors that could cause this condition? Has anyone ever seen a computer act like this? 

[Max Capacity]

FWIW, it took my trusted mechanic about 45 minutes of idling my old 92 Civic, to get it to repeat an ignition module issue, again, an intermittent issue.  So I understand...once the car stalled at his shop, he could then troubleshoot it.

[Tehnation]

No code even when it stalls under 15 mph? Not even a pending? 

Electrical is the worst... it could just be some loose wire.

[Max Capacity]

^   Has the OP tried to jiggle all the connectors he can touch ?

[Tehnation]

4 minutes ago, Max Capacity said:

^   Has the OP tried to jiggle all the connectors he can touch ?

He has been at it for 18 months, I hope he has at least tried lol! 

For ECU problems don't they throw codes at the odometer in instrument cluster?  

[bradyhall]

We've Jiggled and tapped just about everything I can touch to see if anything works. I even tore into the dash to see if there was a loose connection by the ECU. The only code that will pop up if the car dies while idling or just getting going from a stop is the Information center will flash Run System Mode Check. However, once the car decides to start back up the message is gone with no history. Could the flash memory of the ECU be crapping out which would explain no codes and the intermittent issues?? 

[Max Capacity]

So maybe a ECU from the junkyard may fix it ? You'll need to have it paired to your car... I think

[Tehnation]

Yea I was thinking the same thing. Figure out the model or part number for your ecu, get it on car-part.com for like 50-100 bucks. You can pay the dealership to program it or get some stuff of your own and jump circuits and chips to copy and program from your old to new ecu, pain in the ass if you aren't computer savvy! But I think it will work without programing, u just wont have an alarm or something, I could be wrong and it has to be programmed. 

[Tehnation]

 Run mode change system check.

From what I gathered on the interwebs, a lot of subaru people who get that message say its related to electrical issue, like a voltage drop or a bad ground! Something could be crapping out and your voltage drops. Dead batteries etc, will bring up that message. You test your alternator? Maybe the voltage regulator is acting up when it gets hot. 

 

[Enlight]

Ok, this might not be the answer you want, but I would start by testing the very basics. I say this because I was flailing around with my own problems until I decided to undertake a systematic approach. That meant having to build a basis of electrical fundamentals.

Familiarize yourself with the Vacation Pics and the diagnostics troubleshooting sections. Inside those sections they will tell you the voltage you should be getting at various components (i.e. ECU) and what their resistance is supposed to be. It will provide directions for step by step diagnosis.

I would also check your resistance from the battery to various key grounding points (engine block, strut tower, intake manifold). The manual also has information on where those grounding points are and the path the wires take. You will need a multimeter with a wire a several yards long to do that. Connecting the negative lead of the multimeter directly to the battery is important because that will show what resistance the component actually has to overcome. The ECU gets its ground from the top of the intake manifold.

If you have a strong feeling it's a relay you can get a relay tester. This YouTube video (and many of Motor Age's other videos, for that matter) was very helpful to me in terms of establishing an electrical knowledge base.

I'm not sure if any of these recommendations will solve your problem, but the aim should be to gather more information to point you in the right direction. Start from the macro fundamentals which will help you hone in on the micro components.

[bradyhall]

Thanks for all the advice. I will keep you posted on any progress. I'm hoping it is something simple.