mechanicjoe23 Posted July 19, 2019 Posted July 19, 2019 Hello all.. So I recently just bought a 2009 Legacy Gt with 136,000 miles on it. I bought it knowing it wasn’t running right and thought I could figure out what’s wrong with it but now im stuck. The guy I bought it from supposedly had the head gaskets/timing belt/ and water pump done at 122,000 miles. The problem with it right now is the car hesitated and sputters at WOT around 4000 rpm. First thing I found was it had a cheap Chinese air filter setup on it and the air filter was cracked around where the clamp was so it was sucking in some dirty air and also the position of the MAF sensor wasn’t correct either so it had a P0171 code. I bought a stock air box and cleaned the MAF and that code went away, But the problem of sputtering/hesitation is still there. I’ve taken the turbo Inlet hose off and checked for cracks and check the IC to throttle body hose. All good there so I don’t believe this is a vacuum leak issue. Also intermittently the car will take a longer time to start then normal- 5-7 cranks before it fires. Or if I stop cranking it and turn the key off and let the fuel pump prime up again then it will fire right up. I’m beginning to think it’s a weak fuel pump or fuel pressure regulator. Any help would be appreciated. Thanks
Darth SpecB Posted July 19, 2019 Posted July 19, 2019 Do you have the means of testing the fuel pressure? That would be your next step to verify. Sent from my SM-G950U using Tapatalk
DaveWaters Posted July 19, 2019 Posted July 19, 2019 Are you able to monitor real time data? Cobb AP or btssm? With this car a lot of diagnosis will come from seeing how the ecu is trying to resolve problems it perceives. I’d stay out of WOT as you can damage the motor very easily if something isn’t right. Do you know if the car had been tuned? Does it have an aftermarket downpipe?
mechanicjoe23 Posted July 19, 2019 Author Posted July 19, 2019 I don’t really have a way to check fuel pressure at this moment. And as far as real time data I have a WiFi ObII tool that connects to my phone and I can watch live data like fuel trims and stuff. The fuel trims seem to be normal, ranging from -3 to +5. The O2 sensors are a little weird though. Sensor 1 stays at a constant line pattern and sensor to has a up and down wave but sometimes will flat line randomly.
Mr-C Posted July 19, 2019 Posted July 19, 2019 I installed an in line fuel pressure gauge, relatively cheap and easy set up....saved me some headaches. If you do that, maybe get a 0-60 psi gauge for more accuracy...I got 0-100 and kind of regret it. With that kind of millage, maybe the fuel filter is clogged up causing some restriction....worth looking into changing but not an easy job believe me. You might want professionals to handle that.
mechanicjoe23 Posted July 19, 2019 Author Posted July 19, 2019 Ok I’ll have to get one of those. Also today I had just driven the car and stopped somewhere and when I tried starting it just kept cranking but not firing up. I stopped cranking it and turned the key on and off and tried again but it’s still took a few cranks before it fired up. Another thing to mention is I keep getting the check engine light code for the secondary air pump valve stuck open. P2241. Not sure if that really has anything to do with the starting issue and the hesitation.
mechanicjoe23 Posted July 23, 2019 Author Posted July 23, 2019 Touched a vacuum hose today that went to a solenoid on the intake manifold right behind the ac compressor. Right when I touched it the hose came off along with the plastic end. I’m wondering if that plastic end where the hose goes over was hanging on my a little piece and it had a vacuum leak there. The solenoid is supposedly called a cam shaft sensor solenoid valve. Looks exactly like this https://www.google.com/search?q=Subaru+16102AA470&client=safari&hl=en-us&prmd=ismvn&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjpw-DThcrjAhUC0KwKHVeTDAQQ_AUoAXoECAwQAQ&biw=414&bih=622#imgrc=utMtVcBg1yCBxM
Infosecdad Posted July 23, 2019 Posted July 23, 2019 That part name is really wrong. Look up that part number on parts.subaru.com That looks like the OEM boost controller, right over the turbo inlet. That will definitely be a vacuum leak, get it replaced with an OEM part.
mechanicjoe23 Posted July 25, 2019 Author Posted July 25, 2019 It’s actually a HVAC purge valve solenoid. Have it temporarily glued right now while I’m waiting for the new one lol
mechanicjoe23 Posted August 5, 2019 Author Posted August 5, 2019 Update. So I replaced that broken part and also put a new fuel pressure regulator in but the problem is still there
ttnio Posted August 5, 2019 Posted August 5, 2019 do not forget the fuel pump assembly, main part in the fuel delivery.
boxkita Posted August 5, 2019 Posted August 5, 2019 Check your ground cables. I put a ohmmeter on one of mine and found it was open. Outside it looked fine. Build my car Boxkita Track days
mechanicjoe23 Posted August 30, 2019 Author Posted August 30, 2019 So I still haven’t fixed the problem yet. I put a brand new turbo inlet pipe on (which was a pain to do) . I replaced it because I had taken the old one off to check it but tighten the clamp down to tight and ripped the hose. I have no codes except every now and then the check engine light comes on because off the secondary air pump valves getting stuck. I don’t think those are really related to my hesitation problem though. So tonight I did a boost leak test. It was holding air and I couldn’t hear any leaks or nothing and spayed soapy water everywhere and couldn’t find anything. However I watched a video and a guy said to take the oil cap off when doing a boost leak test as you could blow a can seal. So when I took the oil cap off and tried filling the system with air it wouldn’t hold any! It all was coming out of the oil cap.... this has me kind of scared. But I’m wondering if it could be that the PCV valve is stuck open letting air get into the crankcase out the oil filler tube. If it was piston rings I’d be burning oil which I’m not..
ashwinearl Posted August 30, 2019 Posted August 30, 2019 When you did the boost leak test, and took the oil cap off, did you have any other vacuum hoses clamped closed? I have never tried this type of boost tester, because I don't know if and what the exact lines are that need to be clamped. I just recall seeming here in a thread that someone said you'd spray oil out your cap if you did a boost test without the right hoses clamped.
Marvick08GT Posted August 30, 2019 Posted August 30, 2019 Definitely seems fuel pressure related. My first thought goes immediately to the fuel pump assy ( filter mostly ) What condition are the plugs in?
mechanicjoe23 Posted September 1, 2019 Author Posted September 1, 2019 So I did some reading after the boost leak test and I did it wrong. The PCV hoses should have been blocked off thus explaining why the air was getting into the crankcase out the oil cap. And actually I think I may have narrowed down my problem. I unplugged the boost control solenoid....and drove the car...probably not the best thing to do as you can overboost and cause damage plus that check engine light was on when I did it. But I drove it a couple miles and what do ya know, The hesitation and power surging was all gone and it ran smooth thru the entire rpm range. I do believe my problem is related to this solenoid or possible the hoses that go to it or maybe the waste gate actuator is faulty. Gotta do some more research but it does seem like the wastgate is opening and closing opening and closing every time is hesitates. And you can hear it to
Pazuzu Posted September 5, 2019 Posted September 5, 2019 So I did some reading after the boost leak test and I did it wrong. The PCV hoses should have been blocked off thus explaining why the air was getting into the crankcase out the oil cap. And actually I think I may have narrowed down my problem. I unplugged the boost control solenoid....and drove the car...probably not the best thing to do as you can overboost and cause damage plus that check engine light was on when I did it. But I drove it a couple miles and what do ya know, The hesitation and power surging was all gone and it ran smooth thru the entire rpm range. I do believe my problem is related to this solenoid or possible the hoses that go to it or maybe the waste gate actuator is faulty. Gotta do some more research but it does seem like the wastgate is opening and closing opening and closing every time is hesitates. And you can hear it toNah you will just be on wastegate boost I cant even remember what stock wg is set to. I think its like 7 or something. The boost controller just tricks the wg into thinking there is less boost than there actually is so you can boost more than wg spring allows. Sent from my SM-G950U using Tapatalk
Pazuzu Posted September 5, 2019 Posted September 5, 2019 Update. So I replaced that broken part and also put a new fuel pressure regulator in but the problem is still thereIf i was you, i know it sucks. I would check the compression, lets see those plugs while you are there. Then i would pull the downpipe and check turbo condition. That mileage if the turbo is sloppy it could be a time bomb. You can download a diagram of all the hoses and make sure they are all routed correctly. If there is anyone in your area with a tactrix cable you could really see what's going on with your car. Might even be worth it to load a stock tune into it just in case the car was previously modified and parts removed before sale. People selling cars not running well is always iffy. Who was the person you got it from? Did you get a back story at all? Sent from my SM-G950U using Tapatalk
mechanicjoe23 Posted September 30, 2019 Author Posted September 30, 2019 So I finally figured out the problem. It was the boost solenoid. I took it off and put power to it to open and close it and sprayed some cleaner thru it but now the car doesn’t feel like a turbo car. I think it’s running waste gate pressure nowz I also took the hose off the gas the T connector to check it for and leaks and it seemed all good.
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