Baronpilot Posted March 23, 2009 Share Posted March 23, 2009 First post. '96 Outback 2.5 Auto Executive summary: Smog test fail, rich idle, No CEL. Mechanic advises could be Fuel Pressure Regulator, MAF sensor or MP sensor. Any tips? ------- Long Story: I'm trying to help a little old lady with her Subaru. Failed smog. Shop changed O2 sensor, gave up. 2nd shop changed Knock sensor, gave up. Two sensors and frustrated mechanics cost $700. So, I stepped into this mess to help out a friend. When I got the car the major symptom was a surging idle. I decided to work on that before getting another smog test. Changed air filter, Oil and filter. Cleaned IAC valve by pooring a small amount of Seafoam in it, twice. Changed all small vacuum lines. Cleaned MAF sensor with spray, per the procedure on this forum. Idle surge is gone. Car runs well, but upon taking it to my friendly (really, he is...) smog check guy he told me it was "full rich" at idle. Suggested it is one of three things. 1. Fuel Pressure Regulator 2. MAF sensor 3. MAP sensor (Vacuum sensor) Should I test fuel pressure to rule out Fuel Pressure Regulator? Any tips for sorting this out, or experienced guesses? Below are notes from the shops: Shop 1: No notes. changed O2 sensor Shop 2: Check Engine light is on also run too rich at idle speed. Scanner Check shows P0505 Idle Control System. Check for Rich Condition, No codes are present. Scanner Data Shows a Oxygen Sensor Bank 1 sensor 1 stay at .000 MV. Customer replace Oxygen sensor and still not working. We installed a computer and still no change at all. Installed back original computer. Shop 3: Customer states car will not pass smog check. Engine light is on. Check and advise. See attached paper work. Dignostics based on symptoms actual time used for confirming and diagnosing problem with car. Includes time to road test, hook up test equipment and trace problem to it's cause. Check engine light is on check and advise. **** Scanned computer P0325 Knock Sensor Circuit 1 Bank 1. Checked resistance at Knock Sensor (specs are 400K ohms or more) No resistance @ sensor. Recommend replacing Knock sensor and rechecking. Remove and Replace Knock sensor on vehicle. Old sensor had no resistance and causing MIL light to come on. Cleared code and test drove 10 miles and light stayed off. Rechecking .87V - .86V at idle, readings at 2500 RPM .81V-.83V, sensor is staying rich and not switching properly. Install new sensor. After replacing B1S2 O2 sensor mechanic rechecked readings are still the same .81V - .90V staying rich on the downstream side. Re-installed old sensor back in vehicle. Have checked MAF (Mass Air Flow), TPS (Throttle position sensor) etc... Vehicle does have unsteady idle until unplugged TPS sensor and idle steady's out at about 1500 RPM. TPS 0.60V closed throttle, 4.45V wide open throttle. MAF KOEO 0.00, idle 3-4 GS. Called Dealer and spoke to a mechanic to try to get some insight of what step needs to be taken. Was not able to get any info to help cause. recommend taking vehicle to dealer for further diagnosing. Thanks for your time. I'll post results. Quote Link to comment Share on other sites More sharing options...
Olnick Posted March 23, 2009 Share Posted March 23, 2009 One small suggestion--might be wise to remove the IACV and give it a thorough cleaning. Just running cleaner through it may not be enough. Clean the MAF sensor? (Gently spray the fine wires with cleaner.) Check/clean front O2 sensor's electrical connectors. Engine Coolant Temperature Sensor? Good luck--really hope you can help the lady. Quote Link to comment Share on other sites More sharing options...
Baronpilot Posted March 23, 2009 Author Share Posted March 23, 2009 Thanks, Olnick. 1. The surging idle is gone, don't know if it was the vacuum lines or the Seafoam in the input to the IAC valve. In any event, since it seems to be able to control the idle better I thought I would leave well enough alone. The idle surges whenver I push on the brake pedal (idleing, in Park) and then settles right down after a couple of oscillations, so I figure the IAC is fine. Do you think that could cause the rich idle mixture? 2. I cleaned the MAF sensor by spraying the wire with the C&C MAF cleaner stuff. It's clean. 3. I will check and clean the front O2 sensor. Is that the one that I see on the passenger side, just behind the engine? 4. Coolant temp sensor...cost is $40 at Autozone. I will look in manual for testing tips before I replace. That's a good idea. Quote Link to comment Share on other sites More sharing options...
Baronpilot Posted March 23, 2009 Author Share Posted March 23, 2009 OK, one post said that a bad CTS (coolant time sensor) will result in flooding during warm engine restart. This car starts and runs great, warm or cold. Still think it might be a CTS? Any other symptoms? Quote Link to comment Share on other sites More sharing options...
Olnick Posted March 23, 2009 Share Posted March 23, 2009 OK, one post said that a bad CTS (coolant time sensor) will result in flooding during warm engine restart. This car starts and runs great, warm or cold. Still think it might be a CTS? Any other symptoms? My CTS thought might be a reach, but here's my logic: The ECU controls engine operation, including amount of fuel. ECU depends on CTS to know operating temp. of engine. ECU will often go to "open loop" if it gets faulty temp. info and this, I think, can usually mean richer fuel mixture. I may be way off base--and I certainly don't advocate throwing money and parts at a problem. But a new CTS cleared up a lot of problems on my '95 Legacy a few years ago and more recently on my son's '92 Legacy. Hopefully others will chime in with suggestions. Quote Link to comment Share on other sites More sharing options...
Olnick Posted March 23, 2009 Share Posted March 23, 2009 3. I will check and clean the front O2 sensor. Is that the one that I see on the passenger side, just behind the engine? Yes, it's down near the DOJ where the axle fits into the transmission. Try cleaning the pins and receptacle on the O2's electrical connector. Good luck. Quote Link to comment Share on other sites More sharing options...
Baronpilot Posted March 23, 2009 Author Share Posted March 23, 2009 Hi Olnick, Just noticed you're in Honolulu. That is where I used to fly a baron! I used to live in Aina Haina. When you had a bad CTS on your '95 legacy and it went "open loop" (Saab used to call that limp home mode) did it turn on your CEL light? (Check engine light) My CEL is not on. Quote Link to comment Share on other sites More sharing options...
Olnick Posted March 23, 2009 Share Posted March 23, 2009 Yeah--Kuliouou is home! Kids used to go to Aina Haina Elementary, back when the Ranch House Restaurant was still there! Can't remember if I got a CEL or not. Sometimes it doesn't come on but there can still be a stored code. Just checked with my son and he had a stored code on his '92. If you have a code reader (or try Autozone or some parts store--they'll often read them for free) you could check. Or you could check resistance on the CTS with a multimeter. Haynes manual, page 6-7, has the values you should be seeing. Good luck. Quote Link to comment Share on other sites More sharing options...
Baronpilot Posted March 24, 2009 Author Share Posted March 24, 2009 OK, I'll check the CTS tomorrow and post results. I found I can get one from NAPA for about $20. More later.... Aloha Quote Link to comment Share on other sites More sharing options...
pearlm30 Posted March 24, 2009 Share Posted March 24, 2009 Did the exhaust smell rich or like rotten eggs? Change the CTS and see what happen? Could be cat converter??? Dont know much about CA smong test spec. OK, I'll check the CTS tomorrow and post results. I found I can get one from NAPA for about $20. More later.... Aloha Quote Link to comment Share on other sites More sharing options...
Baronpilot Posted March 25, 2009 Author Share Posted March 25, 2009 I'm having problems finding the CTS sensor. I've got one that looks like it in the front of the block, but it only has one wire and the parts diagram shows two. Manuals tell me to look under the intake manifold but am not having luck finding it. This is a 96 Outback 2.5 Liter. Any help would be appreciated. Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted March 25, 2009 Share Posted March 25, 2009 (edited) they're right next to each other on the 2.2, the 2.5L should be the same. see post 14 in this thread re: a 2.2L. http://www.ultimatesubaru.org/forum/showthread.php?t=95900&highlight=temp+sensor 2.5 is the same. http://opposedforces.com/parts/legacy/us_b11/type_45/cooling_system/water_pipe_1/ Edited March 25, 2009 by johnceggleston Quote Link to comment Share on other sites More sharing options...
Baronpilot Posted March 25, 2009 Author Share Posted March 25, 2009 Thanks John. Also found this post: http://www.lovehorsepower.com/SubaruDocs/CoolantTempSensor.html ...methinks I will not be placing a DVM on this very easily. Looks like I'll have to pull it to test it. Quote Link to comment Share on other sites More sharing options...
Baronpilot Posted March 28, 2009 Author Share Posted March 28, 2009 OK, minor setback... I broke the connector in the wiring harness that goes to the CTS. So now I'm writing a post looking for advice on fixing this... Please reply if you have any suggestions.... Quote Link to comment Share on other sites More sharing options...
mountaingoatgruff Posted March 28, 2009 Share Posted March 28, 2009 if you have another connector, you can pull the pins out of the old one and slip them into the other, no soldering. or you can cut and solder. either way, replace the broken connector. Quote Link to comment Share on other sites More sharing options...
Baronpilot Posted April 22, 2009 Author Share Posted April 22, 2009 I replaced the CTS and broke the connector and had a hell of a time finding a replacement, but finally did. Found a cracked crankcase ventilation hose coming out of the block near the CTS. It's about .75 inch diameter. Replaced that. Idle surge is all gone, now IAC is working great. All new vacumn and ventilation hoses probably helped. I STILL have the rich idle problem. So, now that I've ruled out the CTS, what would be the next step? Quote Link to comment Share on other sites More sharing options...
ron917 Posted April 23, 2009 Share Posted April 23, 2009 Check the fuel pressure (or was that done already?) to rule out the fuel pressure regulator. Or, if the part is cheap, just replace it. Possibly a leaky injector (or 2 or 3). Try some injector cleaner - Techron or Seafoam and the like. Maybe sucking fuel or vapor through the evap recovery system or whatever else is connected the mess of vacuum hoses that run to the fuel system. Not even sure if that's possible, just thinking out loud. Quote Link to comment Share on other sites More sharing options...
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