Need ideas on hard starting issue in '94 EJ22

[Subarutex]

Takes 4-5 key turns to start on a good day, will start on first try if its been less than 2 hours since last run.

 

Coolant Temp sensor was replaced less than 3,000 miles ago. Fuel filter replaced a couple hundred miles ago.

 

Any ideas would be greatly appreciated...

[porcupine73]

Coolant Temp sensor was replaced less than 3,000 miles ago

 

Was it the sensor for the temp gauge?

Or was it the engine coolant temp sensor for the ECU?

[Subarutex]

It was teh CTS for the ECU

[illanrob]

I read the thread on hard cranking to start a 94 Legacy with the ECU temperature sensor and fuel filter items to check.

 

My 93 EJ22 5spd does the same and the Engine Code 2-1 (think that is correct ) refers to the Temp sensor flashing. I monitored this sensor at the ECU connector and although it reads a bit low in voltage per the Shop Manual, the voltage moves correctly with temperature. I have reset the ECU codes several times. Noticed that the car will start properly 10 to 15 times, a normal week of driving, after a Code Reset. Have been able to let the car rest during weekends and has been OK for another week.

 

Is all this trouble realy caused by a Temp Sensor?

 

Also noticed that the radiator cooling fans come on 20 secs after a start while the AC is off and the engine has yet to warm up.

 

Any thoughts on this?

 

Robert Illan

93 L 160K 5spd original clutch

[idosubaru]

Is all this trouble realy caused by a Temp Sensor?

it can, yes. what is more often the case (every time i've seen it actually, i've never seen an actual failed sensor) - the sensor contacts are bad. in other words the plug that plugs into the sensor or the contacts on the sensor are corroded, dirty, etc. in worst case scenarios the corrosion gets under the wiring insulation as well.

 

for starting conditions you also need to check the battery terminals and connections. they have to be clean and tight, not just look good from a glance, but actually be clean and tight where metal meets metal (remove and inspect).

[illanrob]

Thanks for the reply:

"it can, yes. what is more often the case (every time i've seen it actually, i've never seen an actual failed sensor) - the sensor contacts are bad."

 

But I wonder if we are talking about the same problem:

The Temp Sensor Code 2-1 flashing could imply that the voltage is missing (bad connection, corroded terminal, broken wire) or the level is off the normal scale. I measured the voltage at the ECU connector, under dash drivers side. The reading was on the lower side of the scale, will have to check my notes on this, from the ShopManual volt temp range but very close.

 

Since the sensor is simply a resistor forming a voltage divider with the ECU, I will try to adjust the voltage some way to be "well" in range this weekend and test how the car starts. The sensor in question does move as the engine warms so it still has life.

 

Robert Illan

Subarus for ever!