My subaru suddenly doesn't crank well!

for something to go bad this suddenly, I would first suspect the battery or one of the battery cables. make sure you check *both ends* of both cables. if the negative cable is not making good contact you will have all sorts of strange behavior (could possibly explain odd alarm behavior).

For the cranking problem, if you've only had the car for a month, I'd take it to the dealer.

For the alarm issue, that's extremely common. On many cars, if you lock the doors with the remote, and open them with the key, the alarm goes off. On most Fords, you can't start the engine.

Two temporary solutions: one, relock and then unlock the door with the remote. Or two, if you don't have the remote, put the key in the ignition and turn it to on and off about five times quickly.

L>>

My cranking problem was solved by replacing the crank sensor. My wife got stuck several times with that problem. As I am a failure analyst, I anaylzed the sensor which had been replaced. I could find nothing wrong with it. I suspect that the connection to it was not quite right. So I think I got charged for a replacement part I didn't need. So, try removing and replacing the connector; it may save you some bucks.

Al

thank you for your reply.

How often does your wife had this problem? does she finally manage to start the car or have to call towing truck?

Since I have never had this problem before, I'll se how it goes.

The problem I had yesterday, is very likely to be a fouled spark plug, that the engine mumbled first(maybe, 1 or 2 cyclinder(s) worked, but the rest ain't) after 2 secs, as the intaking air blowing off the fouled materials off from the plugs, the all 4 cylinder then worked all fine. I can't be certain, since it was only told from someone else, I'll just see if it exhibits the same problem from now on, and if so, I'll give it to the dealer.

I don't think it's the wire part, if it's the coil or so, it should exhibit some wierd behaviour during normal driving. and, it's a brand new car, only bought 1 month.

however, I'll see how it worked.

This happened several times. What frosted her was that when I showed up and attempted to start the car, it would start for me! I don't remember it failing for me though. But, then again, it was the car she used all the time and the failures were perhaps once a week or so.

Al

Yes, but did you ever take the car and actually live with the results of starting it cold, as she presumably did? Did you trade cars, in other words? For example, I was looking at a cheap used lawnmower one time, and the guy wanted to start it for me, and I told him, no, I want to prime and start the machine myself to determine if it was something I, unused to that machine, could start without problems. Good test, got me a good cheap reliable lawnmower for $50.

ok I think I'll take it back to the dealer. becoz today I got another hard start, I have to turn the key at ignition for 5 secs, and the car sputtered at first, keep cranking turned it fully on.

and during driving , if I let off the throttle, the car will sometime jerks backward and forward, it's like it gives a bit gas, then cut off, then give a bit gass again.... it only occurs when let off the gas, and RPM drops around 1500~2000RPM.

Right!

Al

you meant bring back to the dealer is the right idea, or you only got problem during cranking? or the crankshaft position sensor is the main faulty part?

In my case, I took it to the dealer who replaced the crank sensor. If I knew what I know now, I would have found it, taken off the connector and then placed it back again. That might have solved the very intermittent problem I had.

In my case, it would crank, but not start.

There is another sensor called the TDC, top dead center. It lets the computer know when a cylinder is at the top of its travel. This allows the computer to then fire the spark at a suitable time after the compression stroke. If this is intermittent, you may have misfires. Hopefull the spark will be after the TDC and not before it. That really stresses your engine.

I think it cost me about $160 to have the part replaced. Grrrr!

Al

This allows

Sorry, but that's just wrong. In ALL spark ignition engines (correctly adjusted ones, that is...), the spark occurs before TDC. That's since it takes a while for the combustion to propagate. You need to start it before TDC, so the pressure is maximized at TDC.

Larry Van Wormer

Hi,

I was following along ok until this comment...

Most engines fire a few degrees BEFORE TDC (BTDC) on compression stroke to maximize power due to the burn time involved with the fuel charge. How far BTDC depends on engine speed--it may range from zero degrees at idle and go up to 25 deg or more depending on the engine--and must be varied by an external controlling device, thus the spark advance mechanisms built into distributors "back when" before computers took over. The computer doesn't change the actual mechanics/physics required to get the most out of the engine and does the exact same job, just a bit more precisely.

What stresses the engine is firing TOO far before TDC for a given speed. You're correct that EXCESSIVE advance, which leads to pinging or "pre-ignition," can truly hammer an engine, even destroy it in severe cases.

Rick

mine was like it cranked, and the engine shaked a bit, stalled immediately.

2nd attempt, the engine mumbling, shaking a bit more, then stalled again.

3nd attempt, the engine kept mumbling... then vola! it started.

so, it's actually the engine was trying to get started, but just sputtering, mumbling, and shakes... I can feel it, not very noticable. NOT those type that engine does nothing at all. what you recommand? since tomorrow I'll have to get it to the dealer.

btw, the car occasionally will jerk forward and backward, when I let off the throttle during normal driving.

are these two related? so the main suspicion is the crank sensor and cam sensor?

it's a brand new car with 1600km on it. so what will more likely to cause this?

btw, forgot to mention that , the mumbling of the engine in cranking is very like when you didn't press your clutch and RPM drops too low that type of engine sputtering in a manual car.

so hope you can come up with a solution and I can guide the technitians at the dealership.

will it more like a ignition problem? even new Subarus develop igntion problems?