I have a 1993 Impreza L, just ran over 200,000 miles! I am experiencing the hard to start problem a few others have been experiencing. It just keeps turning over, and turning over, but only when it is cold outside. If it is warm out, it fires up after 1-2 cranks. Also usually only overnight when it hasn't ran for about 10 hours. And with winter coming up fast. I need to fix this.

 

My question is for those who got a new ECT gauge, how can the coolant temperature sensor help during start-up, isn't the ECU not paying attention to sensors during start-up?

 

One other thing, those who did put in the new sensor, is it still working good?

 

Any reply would be appreciated

 

Thanks, Max

if the ecu didn't pay attention to sensors when it started, how would it adapt to varying conditions?

 

Coolant temp sensor is definitely an important sensor for start, and especially in the situation you described.

 

It's like 20 bucks at liberty subaru http://www.newsubaru.com

Hump

Originally posted by Impreza_WRX_STi

Hump

 

Did you try the Coolant temp sensor? That's what cause problems in one of my Subarus once. Also, does it smell like gas when you're having the trouble starting it?

Smells like fuel but, not too bad, but sometimes more than others. Also at startup I get a lot of carbon spraying out of the exhaust. It goes away after a few minutes

 

Max

When the coolant temp sensor goes it tends to make the car run extremely rich (flooding) when starting, giving you the hard to start condition - next time try holding the gas pedal to the floor while cranking (what you do if a FI car is flooded) This allows more air in, and it will sometimes start. The sensor is very important during startups.

Thanks, I'll go ahead and get one of those sensors in a week or two before it get really cold out. That is when it get's really hard to start

 

Max

...had the sam hard start you have, mine also would have an up and down idle during that time, do yourself a big favor and get it, be careful that you refill the collant so as not to make a big air bubble in th system, and you should notice about a 20% increase in fuel economy too, mine went from 20 mpg to 24-25 mpg, and no stinky startup etc.

Well this is a good find, I am recently getting very similar symptoms: sometimes hard to start and getting fuel odours after it does. In fact my CEL has been coming on a few times and it's code 21 - coolant temp sensor. I ordered one from the local dealer, going to put it in soon. Any special advice? or is it basically remove and replace? I think the sensor is high enough that there shouldn't be any significant leakage once the sensor is off. And how about sealant? Would teflon tape be advised or some other thread sealant?

 

Thanks.

The ECT sensor has a straight thread and a copper sealing washer, so the tape shouldn't be necessary. A new washer is included with the replacement part. The FSM doesn't mention the tape, although aftermarket manuals do.

I think it has a little bit of tape on it when you buy it,...if i remember correctly. On my legacy, I had to remove a few things to get to it, big rubber air hoses, mainly, and be certain you are replacing the one with 2 wirs, not the temp sensor for the temp gauge, which is nearby, but smaller and looks different, of course, I got them confused, and thought they gave me the wrong thing because i didnt see the right one until i had tried to remove the wrong one...I think the whole job from start to finish, including my confusion, ony took about 2 hours. Do disconnect the (-)battery cable, to get the computer to relearn everything, And I was told to, after the replcement, to start the engine and just let it warm up to operating temp, let the fan go on and off once, before even touching the gas pedal, or of couse driving the car, that worked well for me, saw some other post today about disconnecting and reconnecting the (-) cable, and driving the car, to reset the ignition advance, but when i did that the car would not idle, it kept stalling...??

Thanks for the info!

 

Maximus

Have same problem with 1993 Impreza in cold weather...replaced ECT sensor, reset ECU, then replaced O2 sensors, MAP, new tune-up, new injectors...still problems. My mechanic is mostly bald due to the hair he's pulled out trying to fix this! Now, he says someone told the 1993 has Pre-injectors for cold weather starting! Anyone ever heard of this...and what can be done to fix this?

mine was corrcted with new spark plugs

Any special advice? or is it basically remove and replace? I think the sensor is high enough that there shouldn't be any significant leakage once the sensor is off. Thanks.

 

No significant leakage. The only hassle is freeing the way to the sensor (vac hoses and wires to put aside) and disconnecting it before removing (do you pull or push on the connector's locking tab? I'm never sure which and have to fiddle for some time fearing I'll break something).