(94 legacy wagon - automatic) Having trouble starting with the engine cold. Will start if I slightly depress the accelerator upon start. After engine starts the engine idles properly. Check engine light came on. Pulled the codes. Came up with engine temp senor and air control valve. I cleared the codes, and none have returned yet. When the engine is warm there is no problem starting.

 

I plan on cleaning the IAC with brake cleaner as suggested on the forum.

Any ideas on what are the causes of this malfunction?

Engine Temp sensor messes with the Air/Fuel Mixture - I would bet that is your problem (very common).

 

When the car is cold the computer is getting a signal that it is warm when it is not, and bingo a messed up A/F ratio.

yeah....replace temp sensor....it was like 20 bucks from http://www.newsubaru.com

I had the same problem and the coolant temp sensor never fixed it, I don't what to cover next, and the is no CEL codes?

 

max

Thanks for the comments. The car seems to be running fine now.

 

I cleaned the connectors on both the IAC and temp sensors. Then I applied dielectric grease to the connection (note: in the past, just the engine temp sensor code has come up, and putting dielectric grease on the connector seemed to fix the problem)

 

I'm starting to wonder if the grease on the temp sensor connector boils off due to the heat in this region and then starts giving me bad contact at the connector. A budy of mine mentioned just cleaning the connectors and not using grease as a way to avoid this failure again in the future.... then again maybe the temp sensor is just intermittent and should be replaced.

 

Any thoughts on replacing the sensor since things seem to be working okay now?

Well, after cleaning the plug the idle problem eventually came back. About a month ago, I finally broke down and bought a new temp. sensor. Since replacing the sensor I have had no problems with an irradic idle. Looks like this is the correct solution.

Well, after cleaning the plug the idle problem eventually came back. About a month ago, I finally broke down and bought a new temp. sensor. Since replacing the sensor I have had no problems with an irradic idle. Looks like this the correct solution.

 

Just curious, where'd you get your new temp. sensor and was it hard to install?

I purchased the part at subaruparts.com for $25 plus shipping and handling. The part number for their website is 22630AA041. It was easy to install. First I removed the air intake pipe that runs between the throttle body and the air filter box. Then I unplugged the sensor. Using a deep socket ( I forget the diameter) I removed the old sensor. After doing so some coolant leaked out. I used a rag to plug the hole until the new sensor was ready to install. Then, I installed the new sensor. Placed a bit of dielectric grease on the connector and replaced the intake pipe. There are a bunch of vacuum lines attached to the intake pipe so make sure their all reconnected properly.

 

I did notice quite a bit of scale build up on the old sensor and believe that this may have been responsible for the sensor's intermittent response. You might try cleaning the sensor with some vinegar or appropriate acid, and reinstalling. Its only $25 bucks for a new one, but if you don't have to spend it why do it. If you try this please post your results.

The coolant temps sensor can practically be considered a «wear» intem. It broke down both on my Loyale and Legacy at almost the same mileage, 180,000 kilometers. Condidering the price i would advise replacing it shortly after 100 k miles as preventive maintenance.