Update: Subaru Impreza not starting

A few days ago I posted about my 2003 Impreza. It suddenly stopped on the road, and now will not start even after a jump. I suspected my fuel pump failed. However, I tested it out this morning, and when I turn the key, it does make a low humming noise. At first glance, both my fuse boxes look clean and undamaged. I ordered an OBD2 scanner to try and pick up a code, but I have to wait till next week.

When the car “died”, my acceleration completely stopped, there was no noise when pressing on the pedal, all the lights were still on, and there was no sputtering or jerking. Once I turned the car off, it would not turn back on. It DOES turn over, it just won’t start. The timing belt was replaced right before I bought the car in June I believe. I think I need to check my fuel pressure. Otherwise, I am kind of at a loss for what it could be. Any ideas?

A bad crank sensor will cause a car to shut off and not restart.


Also, it’s unlikely a diagnostic code will be set when the CPS fails.

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Ask your shop to make sure the battery is in good shape and fully charged. Low battery voltage under load can cause weird, unexpected symptoms by reports we get here. Not just the Impreza, many cars. After that, next step, ask shop to determine if problem is no-spark, or no-fuel. Suggest to not presume problem is faulty fuel pump, could be, but that part is pretty robust, not a common failure item. Spark problem more likely. One idea, your shop might be able to check for valve movement during cranking, by peering into the oil-fill hole w/flashlight. Face & eye protection required of course. If nothing seems to be moving in there, indication of a valve-related or timing belt problem.

It makes sense to secure an OBD 2 scanner if you plan to diy’er maintain/repair your car yourself, but I don’t think the scanner will be of much help with this problem. I presume the check engine light is not on.

Likely battery is OK enough to run the ignition system if it can turn over the engine. But of course, running the starter motor runs a battery down more than anything else.

Having your own battery charger is a good thing if you plan to do more than the most basic DIY on your cars.

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An engine needs fuel, spark, timing (both valve and ignition) and compression to start. Because it shut off while running, it does not seem like compression.

If it is a fuel problem, I would spray starting fluid in the intake and see if it briefly starts. If it does, it is a fuel system problem.

To check for a spark problem, watch a utube video of how to remove your spark plugs. I would remove the airc cleaner side, take out a plug andlay it on a metal part of the engine with the wire connected to groud it and see if it sparks when you crank the engine. If it doesn’t ( which I think is what will happen ) You have an ignition or sensor problem. If you have another vehicle handy you can borrow a wire and spark plug from that if it is easier.

If you can’t see the valves through the oil fill hole, remove the top timing belt cover at the top front of the engine and see if the belt is broken or loose.


Use spare spark plug to test spark. Why do folks make extra work for themselves by removing installed plug? 94% of folks can’t even change a plug. Let alone check for spark.

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Because they just don’t have spark plugs laying around? Maybe?


some folks don’t have a spare plug because they don’t keep any old ones.