Stoner Dude Posted August 14, 2018 Share Posted August 14, 2018 (edited) Looking for anyone that has had this issue before. The shop has already performed a cylinder compression test (it was good). Next step is to pull the timing chain cover and start looking into this area. Im already out of money and don't really have a good feeling that this is gonna be the answer, but it's another $400 to find out. Need some help. The car will start and drive good until it warms up and then it totally cuts out where you can barely drive it. 500 miles ago is when this started happening and the first shop changed out the DRIVER side cat closest to the engine (and that fixed it for 500 miles and now it's doing it again.). The current shop checked the cats and they were okay. Could the ECM be malfunctioning? Had a 91 that was doing really weird stuff and getting weird codes. i finally swapped the ECM for another 91 i had and it totally fixed the problem. Anyone know if it's possible to test the ECM? Thanks, Edited August 14, 2018 by Stoner Dude Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 14, 2018 Share Posted August 14, 2018 those are tough to diagnose - but it's something that can only impact one side. If you clear the codes - and then read them immediatly after driving, checking it a few times,a nd then checking it after the check engine light comes on - Is there one particular misfire that shows up first or is it always all three of them together? Make sure the COP's and injectors are good - but it's nearly impossible for 3 robust parts to all fail at the same time. someone had an 01-04 H6 in NY and couldn't track down a one sided misfire on all three cylinders. he sold it and the person that bought it ended up finding massive carbon deposits all in the head and I think doing a head gasket job. is there any timing chain noise? i'd guess the chain/tensioner is problematic or there's massive carbon build up in the head. i guess the first wild and cheap guess would be to seafoam the crap out of the intake in the hopes that it's carbon build up that's cleanable. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 15, 2018 Share Posted August 15, 2018 check the fuel pressure regulator's vacuum line for wet with fuel. check fuel pump for cap/o-ring problem? Quote Link to comment Share on other sites More sharing options...
Stoner Dude Posted August 23, 2018 Author Share Posted August 23, 2018 i went ahead and brought the car home. I took the battery out and had it tested with a hand tester at Auto Zone. It had 43% charge but the guy said it was a good battery. So Im charging it now at 2amp trickle charge. I plan on getting a scan tool and trying to figure out what's going on with this thing. Should i buy a scan tool and which one would be good that has Short and Long term fuel trim data? The weird part is this car starts up fine and you can drive it for a few miles without any issues, and then it totally craps out. I have a hard time believing it has something to do with the mechanical parts of the timing chain, tensioners, or guides. But we shall see. The sucky part is the timing chain cover has like 58 bolts to take out in order to get the cover off. Also, i had the head gaskets replaced probably 15,000 miles ago and they took the heads to a shop to have them check and they were good. Wouldn't they have seen the evidence of massive carbon deposits when they had the heads off? Also, something that puzzles me is that the Bank 1 cat was clogged (glowing red hot) 500 miles ago and was apparently the reason for the initial breakdown. Because after they replaced that cat the car drove amazing for 500 miles. Then broke-down the same exact way. Now a different shop is saying the problem is in Bank 2 with misfire, and they said the cat is not clogged in bank 2. Why would the car break down the same exact way, but a bank 1 cat fixed it before and now its pointing to a timing chain problem in the opposite bank? This engine has two complete separate timing chains for each bank: FYI Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 23, 2018 Share Posted August 23, 2018 (edited) does the car run normally/better immediately after a battery disconnect reset? bafx with a smartphone and torque app might work for you sometimes, sensors can fail at high temp - crank sensor for instance engine temp sensor might be bad, car runs good cold, but the sensor is always telling the ECU to 'choke' because it's cold - if that has been a problem for a long time, might explain cooked cat converter ??? knock sensor can rob power, but they are usually cracked and bad all the time. getting live data may help find the problem so, hope one of the gurus here can spot an issue in the data. Edited August 23, 2018 by 1 Lucky Texan Quote Link to comment Share on other sites More sharing options...
whynot Posted August 23, 2018 Share Posted August 23, 2018 has your fuel mileage changed, if you track it. That could point to an over fuel issue, clogging the cat, then clogging the other one. any way to loosen the manifold before the cat and see if the issue improves, pointing to another clogged cat? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 23, 2018 Share Posted August 23, 2018 If it runs fine when cold, then unplug the upstream O2 sensors and see if that corrects the fueling issues when hot. Sounds like when it goes into closed loop you have an O2 sensor that is skewing your fuel trims. That would probably also explain the converter malfunctions if the O2's are bad. Probably has AFR's in that year. Just unplug them and force open loop fuel maps at all times. GD 1 Quote Link to comment Share on other sites More sharing options...
Stoner Dude Posted August 24, 2018 Author Share Posted August 24, 2018 if the timing chain has slack (due to damaged guides or failing tensioner) or even jumped a link, wouldn't it run like crap even at a cold start up? When running at open loop for a cold start up, does it just bypass all the sensors and fuel trim readings and air intake sensors? Also, if i unplug the O2 sensors at the exhaust to bypass the fuel trim system and it still runs like crap, does that mean that it is for sure a mechanical timing issues with the tensioners/guides/chains, etc.... Thanks, Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 24, 2018 Share Posted August 24, 2018 (edited) AFAIK, open loop is after an ECU reset, just for a few miles or a coupla starts - it begins altering settings as it gathers info from the sensors - not at every start. do you run high octane fuel? It's recommended. Edited August 24, 2018 by 1 Lucky Texan Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 25, 2018 Share Posted August 25, 2018 unplugging the sensor is not a definitive diagnosis. it would be good and easy first step that’s free and easy - particularity considering none of us can see the car and you’ve got the attention of one of the most knowledgeable Subaru gurus around. The help you receive from him will be as good as the info you give - i suggest getting that info Open loop is the engine control maps used before the engine is warm which doesn’t use O2 data. Closed loop is after the engine is warm and uses O2 data . Quote Link to comment Share on other sites More sharing options...
Stoner Dude Posted August 27, 2018 Author Share Posted August 27, 2018 On 8/24/2018 at 12:00 PM, 1 Lucky Texan said: AFAIK, open loop is after an ECU reset, just for a few miles or a coupla starts - it begins altering settings as it gathers info from the sensors - not at every start. do you run high octane fuel? It's recommended. Yes, i have ran high octane ever since i had it at 60K miles. It has 270K on it now. Quote Link to comment Share on other sites More sharing options...
el_freddo Posted August 27, 2018 Share Posted August 27, 2018 After reading this thread start to finish my first thought was the timing chain, then the O2 sensor which I see GD mentioned too. I'd be looking at this/these sensors. If it was timing it'd be doing it from the first start of the day. Cheers Bennie Quote Link to comment Share on other sites More sharing options...
Stoner Dude Posted August 27, 2018 Author Share Posted August 27, 2018 On 8/14/2018 at 1:38 PM, idosubaru said: those are tough to diagnose - but it's something that can only impact one side. If you clear the codes - and then read them immediatly after driving, checking it a few times,a nd then checking it after the check engine light comes on - Is there one particular misfire that shows up first or is it always all three of them together? Make sure the COP's and injectors are good - but it's nearly impossible for 3 robust parts to all fail at the same time. someone had an 01-04 H6 in NY and couldn't track down a one sided misfire on all three cylinders. he sold it and the person that bought it ended up finding massive carbon deposits all in the head and I think doing a head gasket job. is there any timing chain noise? i'd guess the chain/tensioner is problematic or there's massive carbon build up in the head. i guess the first wild and cheap guess would be to seafoam the crap out of the intake in the hopes that it's carbon build up that's cleanable. no timing chain noise except for after i change my oil and start it up, it has a quick zip noise from the engine. Im gonna get one of those BAFX Bluetooth scanners and do as you suggest and I'll get back to this thread with the results. I had the head gasket replaced about 20,000 miles ago and they took the heads to the machine shop and had them inspected and they turned out in good shape. Would they have seen the massive carbon built up at this time with the heads removed? Also, i have used high octane fuel since i got the car with 60K miles. Also, the mechanic that replaced the front driver side cat also cleaned the fuel injectors and i think cleaned the throttle body. It's weird that the cat that went bad 500 miles ago was on the other bank from the side that the cylinders are mis-firing now. Guess it couldnt hurt to seafoam the intake. Quote Link to comment Share on other sites More sharing options...
Stoner Dude Posted August 27, 2018 Author Share Posted August 27, 2018 On 8/23/2018 at 9:20 AM, 1 Lucky Texan said: does the car run normally/better immediately after a battery disconnect reset? bafx with a smartphone and torque app might work for you sometimes, sensors can fail at high temp - crank sensor for instance engine temp sensor might be bad, car runs good cold, but the sensor is always telling the ECU to 'choke' because it's cold - if that has been a problem for a long time, might explain cooked cat converter ??? knock sensor can rob power, but they are usually cracked and bad all the time. getting live data may help find the problem so, hope one of the gurus here can spot an issue in the data. Just ordered the scan tool, thanks for the tip Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 28, 2018 Share Posted August 28, 2018 i wouldn't focus too much on that "carbon build up" comment unless you can find that thread and see how likely it seems. it's third party circumstantial evidence, I was just throwing it out there, maybe you can search for that thread. seems like it was in the last 2 years and was an 01-04 H6 in NY i think. Quote Link to comment Share on other sites More sharing options...
Stoner Dude Posted August 28, 2018 Author Share Posted August 28, 2018 4 hours ago, idosubaru said: i wouldn't focus too much on that "carbon build up" comment unless you can find that thread and see how likely it seems. it's third party circumstantial evidence, I was just throwing it out there, maybe you can search for that thread. seems like it was in the last 2 years and was an 01-04 H6 in NY i think. i think i did read that whole thread, the carbon build up is kinda down on my list for items to focus on. But i can't rule it out just yet. Gonna wait to get my scan tool and run some checks. I found these really interesting youtube videos that explain how to look at the data regarding the fuel trim. i have hope now. https://youtu.be/5WnM_NsOtd8 Quote Link to comment Share on other sites More sharing options...
Stoner Dude Posted August 31, 2018 Author Share Posted August 31, 2018 update: Got my Bluetooth scan tool and trying to figure out how to use it. So i charged the battery up to 95%. started the car up. The check engine light was not on (because i had the battery disconnected it clear the codes). As it getting warm the CEL starts to flash, but then when i rev up the engine the light goes off. It is idling pretty rough and if i rev it up it actually runs really good (in park-no load), and let off the accelerator the engine will die. I have to let off a tiny bit at a time to keep it running. Once my foot is all the way off the gas it will remain idling (rough). No codes are registered except the "pending fault codes" P0301, P0303, P0305. Which is misfire in cylinders 1,3,5. Can anyone tell me if this is the driver side or passenger side bank? The driver side O2 sensor has been bad for a while The next thing i do will be to test the back pressure on the exhaust via the front O2 sensor port with a gauge. Can a clogged exhaust cause the "pending fault codes" as mentioned above? Also, i learn of a super easy way to test the cylinder compression without taking out the spark plugs. Use a amp meter hooked up to the positive cable on the starter. Start the car with the gas pedal floored (to keep it from starting) and watch to see the peaks on the amp reading to see if they are all the same across all cylinders. see video here: https://youtu.be/8YIdqvLCHC4?t=20m40s Also i read about checking the VVT , by swapping the front ones to see if the codes switch sides? So when it broke down in Santa Fe 500 miles ago it was a clogged driver side cat. The O2 sensor was bad on that side as well but it didn't get replaced till i got home after it broke down again the same way. If cylinders 1,3,5 are on the drivers side, I'm thinking maybe the bad O2 sensor clogged the new cat already and that's what's wrong with it now? Quote Link to comment Share on other sites More sharing options...
heartless Posted August 31, 2018 Share Posted August 31, 2018 (edited) 1, 3, 5 are passenger side (right side when in the car) - not drivers Edited August 31, 2018 by heartless Quote Link to comment Share on other sites More sharing options...
el_freddo Posted August 31, 2018 Share Posted August 31, 2018 1 hour ago, heartless said: 1, 3, 5 are passenger side (right side when in the car) - not drivers For "USDM style" vehicles Cheers Bennie Quote Link to comment Share on other sites More sharing options...
Stoner Dude Posted August 31, 2018 Author Share Posted August 31, 2018 1 hour ago, heartless said: 1, 3, 5 are passenger side (right side when in the car) - not drivers Crap, okay. Back to square one i guess. Quote Link to comment Share on other sites More sharing options...
heartless Posted September 1, 2018 Share Posted September 1, 2018 13 hours ago, el_freddo said: For "USDM style" vehicles Cheers Bennie well, considering the OP is in Oklahoma, i would be willing to bet it is a USDM car. 1 Quote Link to comment Share on other sites More sharing options...
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