1996 Legacy is suddenly shutting down while driving! Seeking help on diagnosing/fixing.

[axolotl]

My 1996 Subaru Legacy suddenly started to full on shut down while driving yesterday! It will restart, but needs to be revved constantly to ensure it won't shut down. If it isn't being revved, I can see the battery light on the dashboard appear.

 

A brief timeline:

-Had alternator, belt, and engine replaced about 2 yrs ago

-Was needing to get jumped upon startup consistently for ~1 month, got it fixed & was running perfectly for the next month

-A week ago it began needing jumps about 1/2 of the time to startup

-Yesterday it shut off twice while driving it home, would restart with a jump but needed to be revved. Had battery replaced & an oil change, + fluids topped off.

-Today it can consistently start up without need for a jump, but when testing by driving around my neighborhood it still shut down! Restarted easily.

 

After it shuts down, I've noticed an "alt oil temp" light momentarily will turn on on the dash board.

 

Any help is greatly appreciated, I'm a student on a budget and am looking for ways to fix that are cheap or DIY able. Thank you!

[mikec03]

Check that the voltage at the battery is at least 13.8 v while idling.  I know that you replaced the alternator, but it seems that you aren't getting enough amps.   If it were me, and I know that some people don't like to swap things without total justification, I would go to the junk yard and get a replacement for the alternator to battery cable.  

[john in KY]

Just throwing this out there:  air filter/AFM/balancer coming apart

 

Sounds like you have 2 problems here.

Edited March 5, 2018 by john in KY

[axolotl]

Just tested the amps on the alternator, everything seems to be fine with it, so I'll be moving on to check some wiring! 

[AdventureSubaru]

No check engine light? Alternator is suspect.

 

Failing/bad mass air flow sensors can also cause stalling and poor running conditions.

[axolotl]

I had a check engine light on before my oil + battery change, but after it was gone! Hmm. I'm planning to reevaluate the alternator tomorrow, perhaps I was wrong that it is fine.

[mikec03]

See if you can get the cause of check engine light read!  That could be the clue to all your problems.  When a car is stalling or failing to start, it's never a good idea to ignore a check engine light.

[Fairtax4me]

Typically symptom a bad MAF sensor. Broken solder joint in the sensor. Doesn't always set a code.

Battery was replaced, the old code is probably gone, but you might have a stored code that hasn't turned on the light yet. Look into getting a Bluetooth code/data reader that you can use with your phone. Anything you drive that's newer than 1995 you'll be able to use it on. The convenience is worth the $20-40 you might spend on it.

[mikec03]

It looks like axoloti has left us.  It's kind of hard to continue to help new posters who leave abruptively when they figure out the problem.

[1 Lucky Texan]

maybe he'll come back as a salamander?

 

 

Edited March 8, 2018 by 1 Lucky Texan

[axolotl]

Sorry for my delayed update, busy week!

 

I've had a mechanic buddy helping me out and we've continued to run into issues. Replaced the alternator, then it still continued to shut down. Replaced spark plugs, got a new air filter, shut down a lot less frequently but did still shut down when idling. The check engine reappeared, when it shut down all the electrical components were still on but not the engine.

 

We've now checked the fuel pump, it's all good, cleaned the throttle body, and cleaned up idle air control valve, mass airflow sensor, intake, checked hoses, and checked vacuum leaks.

 

We're closing it up now and are gonna take it on a run, hopefully it's all good! Looks like it was a few symptoms!

[1 Lucky Texan]

what was the code that threw the CEL?

[axolotl]

We checked the CEL today - it was an EGR valve so nothing too concerning!

 

Everything seems to be running pretty well now, drove about 40 miles today without issue. One thing that is of concern, though, is that I found coolant in the oil. I had my oil changed just a week ago at Jiffy Lube! We don't think it's a blown head gasket, so I'm going to go back and ask about it tomorrow.

[axolotl]

So far so good, no issues yet, looks like that did the trick!

[TAML]

HI. new here. This sounds similar to your problem. Seems to be a common problem online, but not here. I had a 1998 Outback from 1998 to last year. Loved it but little things were going on. I live in MN. Gifted it to my brother who is driving it in Donna , Tx. He needed a car badly and no money.

Was fine last year. Now he says it is shutting down at stop signs. too scary to drive. Says it might be leaking oil somewhere too. Sorry, I'm still in MN , but trying to help. It was stored over the summer down there. He took it to Subaru and they ordered him an air control valve which will take 6 days to get. He didn't tell me the cost.

Online I keep seeing an MAF mentioned for stalling problems, never air control valve.

I am just a girl who loved my Subi and miss it. I am trying to help, He does work on his own cars to a point. Not me so not sure if he will listen to me. There are so many Subaru Addicts here in MN. But not sure about TX.

Any info on Stalling Engines on 1998 outbacks.

OH. Info. I had the head gaskets rebuilt or replaced at 60000 mi???? under warranty.  and now it has about 180000 mi I think.

Thanks.

[1 Lucky Texan]

well, there is a dealer north of McAllen.

 

maybe search/ask here: https://forums.nasioc.com/forums/showthread.php?t=1919333 ,might find an independent repair shop.

 

 

 

 

if oil is leaking onto the plugs, that can cause missing, but he may have 2 separate problems.

[sparkyboy]

A dirty iacv will cause a surging during idle, from about 750-1200 rpm every other second or so but not cause the engine to stall. It's easy to remove and clean.

I think you can use any ej maf as long as the plug matches, i am not aware of any diffrences when did they change to map? There must be a procedure to test the maf with a multi meter? I am only familiar with the ea flapper

Sounds like she just needs a tune up

[TAML]

Hi. Sorry . Not a blogger. Didnt know how to respond. My brother found a seems dependable, Subaru in Mcallen. Bert Ogden. They inspected and checked everything. Changed out 2 air control valves and 2 hoses. They drove it a while, 2 weeks I guess, then when ready to return it it shut down again. They returned the car but didnt charge him. Engine light comes on and off. Running ruff. Missfiring and dies. He said he is going to try changing fuel pump next, but going to load it on a trailer and take it back to IA so his son can help him do this.

Thanks much for everyones response.Apptreciate it.