Zoltan Posted October 19, 2013 Share Posted October 19, 2013 1990 Legacy AT. Car has been hard to start in the cold for 8 months. CEL has been on for 2 years. I know I should have done something about it before, but other than hard to start for the last 8 months it ran fine. Car has 180k miles. At first I tried to connect black connector together to read CEL codes but connectors are so close together I could not do it. I did some reading and figured the problem is the coolant temp sensor (the 2 wire one that is for the computer and not the one wire one for the temp gauge) I forgot to mention that when starting the car cold,at at current temps (30 degrees F) it stalls out and needs to be restarted 2 to 4 times and runs very rough for 5 min. If you give it gas or put it in gear she stalls out. Both fans come on right away and this led me to believe that the sensor thinks coolant is hot. So I changed sensor before I read CEL codes with a used one (100k) and no change. Next day I got some alligator clips and was able to read CEL codes. It coms up 21 water temp sensor, 23 air flow sensor and 24 air control valve. My question is, how likely is it that all 3 of these are bad considering all things, one of them being I already changed temp sensor. I am not really that good with electrical trouble shooting (probably because I've been driving subie's for 25 years and have not had any). Can anyone point me in the right direction. Does anyone know what the resistance of the temp sensor should be so I could at least test it. I have had car for last 14 years and do know it's complete history if that would help. Thanks for reading my long post! Quote Link to comment Share on other sites More sharing options...
nipper Posted October 19, 2013 Share Posted October 19, 2013 I am going to take a shot in the dark here, and guess it is the engine temp sensor. Also new plugs will help. Get a new sensor they are'nt that expensive. It is very possible that with age things have gone bad. The ACV (I am assuming thats the idle air control) do get clogged with time. The air flow sensor first check the obvious things, like vacuum leaks. Sometimes a CTS can pass a bench test and still fail. They sometimes develop dead spots in them. nah this isnt a long post, this is rather short What other maint has the car had. Quote Link to comment Share on other sites More sharing options...
heartless Posted October 19, 2013 Share Posted October 19, 2013 start with the first code - coolant temp sensor... there are 2 sensors on this car - a 2 wire unit for the ECU (this is the one you want to change) and a single wire unit for the dash guage. Change the 2 wire CTS sensor for a brand new one (not that expensive) - clear the codes - disconnecting the battery for 30 mins to an hour will accomplish this. Start & drive the car - see if any codes return. If they do, again, address the first one... It is quite common for one issue to cause multiple codes. Quote Link to comment Share on other sites More sharing options...
Zoltan Posted October 20, 2013 Author Share Posted October 20, 2013 Thanks for the help. I will change CTS. Car spent 10 years out east and is very rusty. Also forgot to mention it seems to have developed a small HG leak after I lent car to my brother for 4 months. He was returning it to me on a 400 mile trip and it slightly over heated on a 6000 ft mountain pass ( He drove it much harder than I do, 80 mph). It boiled over he said it didn't over heat to bad. IT drives fine and does not over heat when I just putter around town, does blow bubbles in the over flow tank though. I just want one more winter out of it, maybe 2000v miles. It is my sacrificial salt car. I own 3 other 1st gen legacy's. My wife and I each have a rust free summer one, and then our rusty winter ones. I Love my Subaru's, neighbours used to think I was crazy, now they drive subaru's. My entire Family does, 12 cars or so. Anyway not driving problem car currently, will not have a chance to work on it for a few days. Will post the solution. Thanks again for taking the time to help. Quote Link to comment Share on other sites More sharing options...
heartless Posted October 20, 2013 Share Posted October 20, 2013 if she is blowing bubbles into the overflow, you definitely have a problem. You might be able to baby it thru the winter, but I wouldnt count/plan on it. It is possible to change the headgaskets on the 1st gens without pulling the motor - you may want to consider doing the job now - before things get worse - rather than waiting until it fails completely in the dead of winter... Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted October 20, 2013 Share Posted October 20, 2013 Once you replace the CTS, clear the codes stored in the ECU and see how the engine runs. Quote Link to comment Share on other sites More sharing options...
Zoltan Posted October 21, 2013 Author Share Posted October 21, 2013 Changed CTS, cleared codes. CEL gone,car starts great!! Was thinking of changing head gaskets, but car will be scraped in April, not sure how bad it was over heated, and it's not that hard around here to find low milagae first gen Legacy's for dirt cheap. They very rarely seem to have a head gaasket issues. I'm also kinda interested in how long I can nurse this car. Thanks again heartless and nipper great advice!!! Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 21, 2013 Share Posted October 21, 2013 If youre gonna scrap it, just keep a close eye on coolant level over the winter and just be easy on it. Should last that long no problem. Quote Link to comment Share on other sites More sharing options...
Zoltan Posted October 21, 2013 Author Share Posted October 21, 2013 Will do. Quote Link to comment Share on other sites More sharing options...
heartless Posted October 22, 2013 Share Posted October 22, 2013 Changed CTS, cleared codes. CEL gone,car starts great!! Was thinking of changing head gaskets, but car will be scraped in April, not sure how bad it was over heated, and it's not that hard around here to find low milagae first gen Legacy's for dirt cheap. They very rarely seem to have a head gaasket issues. I'm also kinda interested in how long I can nurse this car. Thanks again heartless and nipper great advice!!! Yay - glad to hear she is starting properly for you. Quote Link to comment Share on other sites More sharing options...
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