I could probably write a book on this, but I'll try to keep it as concise as I can.

 

The victim:  95 legacy wagon, ej22, auto,  awd,  250k miles

 

The symptoms:

 

 Intermittently stalls/dies/sometimes just hiccups. - Happens every couple of days most often after a hot soak.  So far, will restart immediately.

 

 There is a relay repeatedly cycling on and off under the dash- only when in gear, seems to cycle faster as speed increases.  Fairly certain it is not the fuel pump relay or main relay,  clicking.

 

No codes in ECM.  On one occasion, TCM set code 23 (engine speed signal).

 

Driving along with a code reader connected, reading live data, it will sometimes loose communication with the ECM.  This is sometimes, but not always, followed by a hiccup/stall. Code reader does not seem to lose power.

 

 

Tried so far:  Swapped coil, threw a crank sensor at it.(cheap, why not...)  Cleaned up as many grounds as i can find.   Fuel pressure +-32psi-( need to rig up the gauge so I can monitor while driving). Battery & alternator test good.

 

 

I have a hunch that the ECM is beginning to get flaky. I say this because even if I start unplugging sensors, it will not set any codes. (except for the TPS)  Just wondering if I'm missing something obvious.

 

 

Any suggestions/advice greatly appreciated.

 

-Bob

Edited April 27, 201411 yr by Silent Bob

Corrosion at the relay connector I bet.  Find the source of the clicking and inspect the connector.

 

Just pulled one from a friends 97 Impreza there was green crap growing out of it.  The main relay way up under the dash on the drivers side.

 

Check out www.brigherideas.com or go to youtube and search LoadPro.

 

Dan has lots of great electrical training information.

 

Does the engine actually die or does it just go back to idle?  If it's going to idle it's the MAF.

Larry

Edited April 27, 201411 yr by lmdew

This sounds like corrosion, now the question is where. I have never seen it at the main relay, but I have seen it under the main fuse box under the hood (and if applicable the fuseable links). Can also be a rotted wire in the same area. This actually is not a unusual thing on older subarus.

I would say its the MAF causing the stall/hiccup issue.

 

The clicking sound in the dash is not normal, but it doesn't seem related.

 

If it clicks when in gear can you set the parking brake and chock the wheels and poke under the dash to find the source?

 

Does it make the same click noise if you tap the brake pedal repeatedly?

Update:

 

Clicking noise turned out to be the trip meter which coincidentally got stuck at the same time.  So, total red herring there, but at least not driving me nuts anymore...

 

Fuel pump& main relay  & connectors look nice and shiny.

 

Dug up a spare MAF out of the pile-o-parts.  Figure I'll swap that out after lunch & see if is makes a difference.