Loss of Power while Idling?

[toolazyforalogin]

I have a 2011 Legacy (non turbo) with 62,000 miles. I'm noticing that when the engine is running and I'm stopped either at a stop sign, red light or if I'm parked with the engine running and I turn on the A/C, fan blower or even just rolling up and down the windows the car will shake a little bit and I can "hear" the car trying to get power.

 

I'm asking all of you experts what you would do in my situation. Should I have the alternator checked? I haven't changed plugs/wires yet if that could be the issue.

 

The car used to get driven daily 40 miles to work each way. Now it makes shorter trips, only about 2 miles to work each day. I'm not sure if maybe there's some buildup in the engine that needs to burn off since the engine is not getting hot enough on my daily commute to work. I was thinking maybe a treatment in the gasoline?

 

Thanks in advance everyone. I appreciate the help.

[FLlegacy]

Sounds more likely to be a spark plug/air filter/MAF dirty issue. Those are easy enough to check out.

[toolazyforalogin]

Thanks for the feedback. I can check the air filter easily. Spark plugs I'm a little apprehensive about - is it just unscrew, check for dirty/clean - maybe rub a little sandpaper over the bottom where it sparks to clean and replace?

 

IIRC the MAF sits on top of the intake body. I'm assuming I just pull it off and clean it off with the same product listed in this thread:

http://www.subaruoutback.org/forums/99-do-yourself-illustrated-guides/55657-diy-gen-4-maf-mass-air-flow-sensor-cleaning.html

 

Thanks again for the help

[FLlegacy]

Yes that is what is used to clean it. Disconnect the battery, clean the MAF, reinstall sensor and battery cable. You can check the air filter while you are doing that. The plugs on the 2.5i i am not sure about, but they may also be coil on plug which means, pull the coil-->then remove the plug and check/replace as needed.

 

You could also grab a multimeter and check your battery voltage when cranking it should stay above 10 volts at a minimum if it dips close to 10 or lower then you may want to have it checked professionally.

[08SpecB_DE]

You can try cleaning the throttle body as well. I suggest having someone sit in the car, turn the key to the on position but do not start, then push the gas pedal all the way down. While they hold it down, the plate should be open allowing you to spray some throttle body cleaner inside. If it's real dirty I like to use an old toothbrush at first, then wipe it clean with a rag.

[DugsSin]

Are you still running the original battery?

[toolazyforalogin]

You can try cleaning the throttle body as well. I suggest having someone sit in the car, turn the key to the on position but do not start, then push the gas pedal all the way down. While they hold it down, the plate should be open allowing you to spray some throttle body cleaner inside. If it's real dirty I like to use an old toothbrush at first, then wipe it clean with a rag.

 

I'm not sure where I should be looking for this plate but I can try later this week when I get someone to sit in the car for me. Just spray throttle body cleaner and then I'm assuming it will evaporate? Should I wait an hour or so before starting the car afterwards?

 

Are you still running the original battery?

 

Yes I have the OEM battery which is 5 years old last month. Maybe I should invest in a new battery so see if that's my issue?

 

 

I cleaned the MAF sensor earlier and my basically new air filter was clean and virtually flawless. The power loss I'm experiencing is not to the point where the car will shut off but you can definitely hear and feel it and my idle rpms drop slightly. I have not checked the plugs because I don't know where they're located or how hard it will be to take them out. I've never changed spark plugs myself but I do have the proper socket to do it if it's accessible.

 

Again thanks for the feedback everyone.

[FAILBOT]

Replace your battery regardless at this point. It's pretty much at its end of life after five years. You are also taxing the hell out of it at this point driving that short of distances now. Your car uses the battery to start the car and your alternator to run it and charge the battery. Now that you are driving such a short distance, it doesn't have time to charge it back to its full potential. This will become more and more noticeable as the battery gets older. Since the battery is weak, the alternator will start to get taxed as it's charging hard to maintain the battery and supply power to windows, blower motor and so forth. Before you know it. Your car won't start.

Note: Not saying this is why your car is having those issues, but it's a need to be done thing at this point.

[08SpecB_DE]

I'm referring to the throttle body plate inside the throttle body. You spray the cleaner inside and wipe it down or scrub it to get it clean.

[toolazyforalogin]

Replace your battery regardless at this point. It's pretty much at its end of life after five years. You are also taxing the hell out of it at this point driving that short of distances now. Your car uses the battery to start the car and your alternator to run it and charge the battery. Now that you are driving such a short distance, it doesn't have time to charge it back to its full potential. This will become more and more noticeable as the battery gets older. Since the battery is weak, the alternator will start to get taxed as it's charging hard to maintain the battery and supply power to windows, blower motor and so forth. Before you know it. Your car won't start.

Note: Not saying this is why your car is having those issues, but it's a need to be done thing at this point.

 

That's a good idea. I'll take care of that next weekend. Thanks.

 

I'm referring to the throttle body plate inside the throttle body. You spray the cleaner inside and wipe it down or scrub it to get it clean.

 

Just to confirm the throttle body plate is at the end of the intake?

 

Also I found an article about relearning the idle procedures for the an Outback. Might be the same on the Legacy. The article is located here:

 

http://www.justanswer.com/subaru/6z0sc-subaru-outback-2-5i-basic-replaced-battery-alternator.html

 

Thoughts?

[toolazyforalogin]

Actually I was trolling on the Outback forum and came across this idle relearn procedure. Not sure if it's necessary when I replace the battery or not. I'll probably try it:

 

How to Idle Re-Learn after Battery Disconnect

Posting here as this seems to affect some Forester and Imprezza models with Electronic Throttle Bodies or IACV that undergo a battery disconnect, and lose their idle calibration.

 

As per THIS POST and ANOTHER POST and THIS OTHER POST and YET ANOTHER POST to retrain the ECU idle parameters:

 

1) Turn off the lights, aircon, stereo or any system in the car that draws extra current on top of the engine.

2) Disconnect the battery for 30 mins.

3) Reconnect the battery.

4) Before you start the car for the first time, turn the key to the ON position but do NOT turn the engine over. Wait 10-15 seconds so the electronic throttle body or IACV has time to go to the factory programmed home position.

5) After waiting, start the car and let it idle without any load, lights, A/C etc.

6) Every 20 seconds or so the idle will be adjusted up and down as the ECU tries to adjust it towards a stoichiometric fuel / air mix.

7) Leave the engine running for a full 10 mins but DO NOT TOUCH THE ACCELERATOR during this time or turn on anything that will cause extra electrical current draw.

8) Turn off the engine, and leave the key in the OFF position for at least 20 sec.

9) As per step (4) turn the key back to the ON position for 10-15 sec without actually starting the engine.

10) Start the engine and leave to idle for a further 5 minutes without touching the accelerator and without turning on other systems in the car.

11) Turn off the engine again and wait at least 20 sec before restarting.

12) Take the car for a test drive as the ECU should now be fully retrained.

 

--------------

 

I know for a fact that this is necessary for the 2003 Forester XT because this process seems to have been the cause of all the teething problems with the LPG system because it was never retrained after the battery was disconnected during the conversion. I used an OBD2 adapter to measure the AFR beforehand - and the LPG AFR was waaay out in comparison to the petrol. After following the process above both sets of AFRs are now very close to a stoichiometric mix, and the car idles correctly without the revs bouncing up and down constantly.

[FLlegacy]

This is an older engine but the position of parts is the same, the blue "circle" is the throttle body. Inside of that is the throttle plate.http://i145.photobucket.com/albums/r236/CadiLLacPimPin97/IMG_0105-1.jpg

 

It will look like this:

http://ebayapi.loc8apartltd.netdna-cdn.com/00/s/MTIwMFgxNjAw/z/hG4AAOSwzgRW1gfF/$_1.JPG

[FLlegacy]

Actually I was trolling on the Outback forum and came across this idle relearn procedure. Not sure if it's necessary when I replace the battery or not. I'll probably try it:

 

How to Idle Re-Learn after Battery Disconnect

Posting here as this seems to affect some Forester and Imprezza models with Electronic Throttle Bodies or IACV that undergo a battery disconnect, and lose their idle calibration.

 

As per THIS POST and ANOTHER POST and THIS OTHER POST and YET ANOTHER POST to retrain the ECU idle parameters:

 

1) Turn off the lights, aircon, stereo or any system in the car that draws extra current on top of the engine.

2) Disconnect the battery for 30 mins.

3) Reconnect the battery.

4) Before you start the car for the first time, turn the key to the ON position but do NOT turn the engine over. Wait 10-15 seconds so the electronic throttle body or IACV has time to go to the factory programmed home position.

5) After waiting, start the car and let it idle without any load, lights, A/C etc.

6) Every 20 seconds or so the idle will be adjusted up and down as the ECU tries to adjust it towards a stoichiometric fuel / air mix.

7) Leave the engine running for a full 10 mins but DO NOT TOUCH THE ACCELERATOR during this time or turn on anything that will cause extra electrical current draw.

8) Turn off the engine, and leave the key in the OFF position for at least 20 sec.

9) As per step (4) turn the key back to the ON position for 10-15 sec without actually starting the engine.

10) Start the engine and leave to idle for a further 5 minutes without touching the accelerator and without turning on other systems in the car.

11) Turn off the engine again and wait at least 20 sec before restarting.

12) Take the car for a test drive as the ECU should now be fully retrained.

 

--------------

 

I know for a fact that this is necessary for the 2003 Forester XT because this process seems to have been the cause of all the teething problems with the LPG system because it was never retrained after the battery was disconnected during the conversion. I used an OBD2 adapter to measure the AFR beforehand - and the LPG AFR was waaay out in comparison to the petrol. After following the process above both sets of AFRs are now very close to a stoichiometric mix, and the car idles correctly without the revs bouncing up and down constantly.

 

 

Not sure where you are, but the XT forester wasn't available in the USA until 04 MY, but I don't know if it had dbw throttle or not. Even still, the newer engines are capable of adjusting the throttle on the fly many of us have this issue when loading a new tune, the throttle acts funky for a few minutes then returns to normal with a few minutes of driving no special instructions needed. Most of those links reference pre canbus ecu's.

[toolazyforalogin]

Thanks for the pics. I will try to take a look this week. If I'm spraying in the cleaner should I do it sparingly so that I don't get any extra fluid inside the throttle body? I don't want to mess something up - maybe spray it on a rag and just wipe the plate down would be the best best? And if it is in that position I would have no idea how to reach all the way up there and blindly clean that plate. I think it's pointing towards the passenger side on my 2011

[FLlegacy]

It should be fine it shouldn't hurt anything as long as it is safe for fuel injected vehicles.

[08SpecB_DE]

You want the plate open so you can clean the backside of it as well. I would avoid spraying a whole can but you want it as clean as possible. There's a good chance it will take a few extra seconds to start due to the process but it's nothing to be concerned about.

[toolazyforalogin]

Just want to update the thread. I did change the battery out and it has not fixed my issue. I have NOT been able to spray the throttle body with the cleaner yet. The throttle body face the interior of the car if I remove the intake and I can't see it since it faces the rear of the car. I am not comfortable taking it off so I may have to have either the stealership or a local mechanic take it off and clean it.

[Perscitus]

I'd also recommend logging some SSM params using either RomRaider's logger (Tactrix OP v2 via a laptop) or BtSsm (with BtSsm dongle or Tactrix OP v2 via an Android device).

 

Would be good to know your IATs, EGR steps/cycle, Total Timing, Learned Timing, etc.

IAM and Learned View snapshot would be a plus.

 

Your Fuel Trim A (active and learned in CL at idle, and a bit below and above) might also be very lean or rich (likely rich) causing the bogging.

 

I wouldnt be surprised if (based on what your seeing) with high enough IATs, some of the compensation tables (timing, load) are kicking in and pulling enough timing to make her bog while idling like that.

 

What's your battery reserve capacity and resting state voltage after sitting on the car for say 12-24 hours since last drive? What's the average voltage while alternator charging at idle or at 2k rpm?

 

Did you trickle charge the new battery after purchase prior to install or once in the car so it would reach full capacity? Most 'new' batteries are sold discharged after sitting for weeks/months on a shelf or in a warehouse rack. It can still be discharged and the stock alternator battery circuit will never fully charge it on its own.

[YeuEmMaiMai]

Are you still running the original battery?

 

I dunno, my battery lasted me 8 years before I replaced it in my Cl-S...the second one also lasted 8 years and just now needs to be replaced... the one un the 2003 Subaru Legacy was 6 years old when I bought it and it was working just fine when I replaced it... the one in the '14 legacy however does appear to be weak sauce despite it's size.

[FLlegacy]

New batteries are not as good as the older ones, mine have been going about 3 to 4 years since our 2007 legacy.

 

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