Intermintant car won't start

So, 05 legacy gt limited, turbo, 5eat tranny, 250k miles. Runs great, good compression. New fuel pump, plugs, cam sensor.

 

When it starts it runs great, after it sits, sometimes not all , it won't start. It cranks fine but won't run. Either no fuel or no spark.

 

The fuel pump was not holding pressure so we replaced it. The fuel rail check is holding pressure. I also replaced the fuel pump relay. It didn't start at first put then started right up 6 times in a row. So we will see. Just in case I figured I post if anyone had any other ideas.

 

Thanks

Hard to diagnose on this venue. Could be soooo many things. After replacing 2 ecu's and 2 BIU's, my similar trouble was in the instrument cluster.

How old is the battery ? are the terminals clean and tight ?

 

It the wire on the starter clean ?

 

How are all the grounds on the car ?

 

I hope you would have checked those before you replaced parts.

How old is the battery ? are the terminals clean and tight ?

 

It the wire on the starter clean ?

 

How are all the grounds on the car ?

 

I hope you would have checked those before you replaced parts.

 

the battery is new, and it cranks fine. the problem is not with it not cranking it is with it not firing.

 

it seems to be running ok now. I just wish I would have thought about the fuel pump relay sooner, as it has started every time since.

the pump was failing but may have lasted a bit more.

the only reason I posted was incase it starts to do it again . I am new to the subis but not cars. and don't know the quirks of them yet.

 

in the old days it was either no fuel or no fire. points, coil. if you had power to the coil and the points were opening and closing and it would not fire it was probably fuel. now if it fires but sputters and shakes it could be timing, bad plug. bad gas, bad wire etc... with it not even firing as all of the plugs have separate coils it has to be either no fuel or something electronic. cam sensor, ecu, ? this is all new to me.

Let me know if that keeps it running. I have a similar issue.

 

Thanks!

Hailey

Well , still so far so good, we will keep our fingers crossed that it was the fuel pump relay

What about the Crank sensor?

^^^Beat me to it.

We replaced the crank sensor and it started right up. Took it home and the next morning it would not start again. So we were right back where we started. That's when he did the pressure test and saw the pump leaking down. I inured it was leaking down and creating a air pocket in the system, thus the no/hard start. Aft t he pump replac,ent it worked for a bit then same. That's when I suggested the relay. So far it has been 4 days now and It has started every time. So I am crossing my fingers.

My problem after careful research,,,,,was that I was simply taking too many short trips.

 

I do believe we have similar engines,,,but the additional strains put on the battery/ recharge system say through the nav. System which draws a lot believe it or not was the problem.

 

Monday,had to call a friend to jump start me,,,,,,,,which it did instantly.

 

Just something,,,,,,non technical to consider.

 

I've heard it takes 10 miles of driving simply to get back what you lost in starting power...

Ya, the battery was never the prob. But you do have to make sure that all the connections are clean and tight. Ad the connections to the alternator are tight. Again the problem is not with cranking. It cranks like a charm, just didn't fire.

 

Hopefully the relay has. It fixed so I can move on to the bigger problem with the car.

Alternators are NOT battery chargers. They are simply battery maintainers. Your battery MUST be good and fully charged for everything to work correctly. If you have to jump your car to start it, you would be better off NOT doing it, removing the battery, either charging it or replacing it, and THEN starting and driving the car.

 

Internal regulator alternators are absolutely FRAGILE and in almost all cases are set to operate at 75-80% of capacity at normal usage. This allows the diode plates to pass enough air over them to cool them sufficiently and operate as it should. When you jump your car, your alternator immediately goes to 100% of capacity as it's trying to make up for the reservoir (battery) being empty and when the alternator goes to this amount of output, the heat sinks and internal fans are simply not enough to sustain the cooling for very long.

 

In Ford 3AG and also GM CS units, it can be as little as 5 minutes after a jump and the alternator has gone to 100% of capacity that the alternator actually loses a diode and then you're replacing both the battery and alternator.

 

It's simply not worth it to jump start cars now as the other downstream ramifications caused by a bad battery are expensive and time consuming to repair.

Ok so now I'm lost, would not start at all this morning. Finally this afternoon it started and the check engine light was on. So I went and got my iPad and wifi interface. Said it had

Stored code

P0335

Crankshaft position sensor “A” Circuit

 

Pending code

P0420

Catalyst system efficiency below threshold bank 1

 

But I replaced the crank sensor. Oh well back to the drawing board!

Sounds like the front O2 sensor is on its way out.

 

Did you the keep the old crank sensor ? Next would be to check the sensor wires for a break.

Both o2 sensors are new, replaced them 3 months ago.

 

The wires or connectors were what I was thinking also. Could have a pin pushed back and not making good contact.

Good luck, I hate electrical problems.

Ya, I'm about to drive this pos into a wall! It is so spontainious its driving me crazy.

Have you checked out the ignition switch ? it could be worn.

 

How does the key feel when you turn it to start ?

Interesting thought, has this been an issue. I figured that these newer cars controlled the ecu. Unlike the older car switches.

These damn things manufacture problems all by themselves. I had a pretty new front NTK O2 sensor (about 8 months I think) and it dumped but never set a code or CEL or anything. Car started doing all kinds of goofy crap-surging, turbo sounding like it was pulsating, get 27 m.p.g. one day and then 18 m.p.g. the next with no change, and it happened sitting in the garage. Parked it one evening and it was running fine (or so I thought)-came out about a week and a half later, started it, and bam-surging at idle (STFT from -25 to +25) and the car would just about not drive.

 

I changed it with a new OE Subaru O2 sensor, and the difference was absolutely amazing. It apparently had not been running to it's full potential for a little while because all of a sudden it idled perfectly, the boost felt stronger and smoother, and it even is a bit quieter (had 2 different people comment on how it sounded quieter) with 3" CBE.

 

Think about your O2 sensor too. This was my third in 90K in the front and it's beginning to piss me off.

 

These things eat coil packs too. Twist the pins in the packs slightly to make sure you have good connection if you remove them to replace plugs. Subaru in their infinite stupidity did not make the coil plugs replaceable without changing the entire wiring harness. It would have been so damn easy to make the ends just pigtails coming from a larger plug but that would have made sense.

Thanks jm, yea it has been a pain, I work in the film industry doing special effects, so I deal with electronics ie fireing boxes for our pyro and and relays, solenoids and such.

 

It's so hard to troubleshoot when they work so randomly.

2 new oem o2 sensors a couple of months ago because it was throwing a cat code. New belt and such last month for regular maintenance. This is just a new thing that popped up within the last couple of weeks.

 

These cars are great when they work but a pain when they don't!