phil527 Posted August 20, 2007 Share Posted August 20, 2007 I changed my coolant temp sensor before my last trip based on posted advice on this board and got a 3 mpg improvment!! Paid for itself in one trip. '98 2.5 outback, 118K, 27.5 highway mpg, cruising 70-75 with the car loaded with the family and gear. I did not have and specific engine codes or CEL, the only symptoms were a drop in my highway mpg to about 24 for some time, and some hard starting last winter in extremely cold weater (-5 F and below range). It would start fine when the temp came up to the teens. I changed the front O2 earlier this summer, it ran a little better but mileage was still off. All thanks to the wealth of knowledge on this site! Now I just need to change the plugs and wires before the next trip -it was just too hot and humid to do it when I did the CTS. Quote Link to comment Share on other sites More sharing options...
Cougar Posted August 20, 2007 Share Posted August 20, 2007 It's nice to know that the info from here helped you out. Thanks for the feedback. Quote Link to comment Share on other sites More sharing options...
OB99W Posted August 20, 2007 Share Posted August 20, 2007 I changed my coolant temp sensor before my last trip based on posted advice on this board and got a 3 mpg improvment!! Paid for itself in one trip. '98 2.5 outback, 118K, 27.5 highway mpg, cruising 70-75 with the car loaded with the family and gear. I did not have and specific engine codes or CEL, the only symptoms were a drop in my highway mpg to about 24 for some time, Great ; it's good to burn less gas and help keep the air around Ithaca clean. and some hard starting last winter in extremely cold weater (-5 F and below range). It would start fine when the temp came up to the teens. I changed the front O2 earlier this summer, it ran a little better but mileage was still off.I don't want to rain on your parade, but it's unlikely that the new O2 and coolant temperature sensors will help with hard cold-weather starting (the ECU, of course, runs open-loop until the engine is sufficiently warmed)... [...]Now I just need to change the plugs and wires before the next trip -it was just too hot and humid to do it when I did the CTS....but new plugs and wires just might do the trick . As you may have already read here, using OEM parts for those is key. Quote Link to comment Share on other sites More sharing options...
rfederici Posted March 17, 2017 Share Posted March 17, 2017 Don't Know if this is the right place to ask this. Our 2007 Outback has gotten hard to start in temps below 30F. The car has 185000 miles on it. Engine cranks over like it should, but it just won't run. No check engine light. So far I have replaced:Coolant Temp sensor MAF sensor Cam position sensor Crank position sensor Then on one of its no start episodes I gave it a blast of starting fluid. It then started. This led me to believe that the problem was the fuel pump, so I replaced that as well yesterday. The pump was a new complete assembly P/N 42021AG11A. This morning 28 degrees F. It started but, cranked for a while before catching. What am I missing here? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 17, 2017 Share Posted March 17, 2017 First of all - stop troubleshooting with Visa. When the engine is cold you need to check the ECU live data and get an idea of what the engine is "seeing". Does it see the cam and crank sensors (tach reading), does it think it's 70* outside (coolant temp), does it think it's on top of Everest (MAP sensor), etc, etc. A generic OBD-II scanner that will do all this is about $50. GD 2 Quote Link to comment Share on other sites More sharing options...
idosubaru Posted March 17, 2017 Share Posted March 17, 2017 What engine? H4 or H6? Read the codes - the check engine light isn't on doesn't mean it doesn't have codes. Are you positive the check engine light works? Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted March 17, 2017 Share Posted March 17, 2017 next time you feel it will fail to start - cycle the key from OFF to ON (not START) , several times(4-5-6 ?), wait 3-5 seconds at ON each time. then, try to start it. If it reliably starts better, somewhere you are losing fuel pressure - maybe tighten fuel line clamps. Quote Link to comment Share on other sites More sharing options...
rfederici Posted March 17, 2017 Share Posted March 17, 2017 Engine is H4, scan tool shows no codes. Live data shows Coolant temp @ 59C ( ambient air temp today is 51F) RPM reading around 800, Shows Intake Air temp @21C(69.8F), and shows ambient air temp @2C (35.6F) I see a difference, is this normal or is some other sensor acting up? The Fuel system at the pump has Quick disconnects (2) and they are not leaking. I considered the loss of fuel pressure being the culprit and then elected to replace the fuel pump due to the fact that the car has 185,000 miles on the original fuel pump. I appreciate all of your help. These cars are supposed to be good in cold climates, and up until this past winter this car has been good.. What am I missing? Quote Link to comment Share on other sites More sharing options...
Dj7291993 Posted March 18, 2017 Share Posted March 18, 2017 If the car was warm, engine bay air (iat) will be warmer than outside air. However, it is a bit odd that it thinks ambient air temp is low. May be an indication of an issue. The best time to check those sensors is Key On Engine Off after it has sat overnight. All the sensors should be within a few degrees of each other at that point. Quote Link to comment Share on other sites More sharing options...
rfederici Posted March 18, 2017 Share Posted March 18, 2017 I will check that before my next cold start. Thanks. Quote Link to comment Share on other sites More sharing options...
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