Subaru Crosstrek and XV Forums banner

61 - 80 of 115 Posts

·
Registered
Joined
·
24 Posts
So I made the mistake of thinking this engine only has 1 knock sensor - I was incorrect.

I replaced the knock sensor, torqued it to 17 ft-lbs and went for a drive...noticed that I still had the bog as it warmed up. :unsure:
So upon more digging, I realized that the FB20D has 2 knock sensors - 1 for each bank. Shoulda looked into it more thoroughly!
The driver's side one is easy enough to get at with a socket extension - the passenger side, not at all.
Clearly the driver's side knock sensor was not the problem.
Both are under the intake manifold and mount directly to the engine block.


I'll leave that for the dealership to troubleshoot further, but I'm not giving up on getting this solved!
 

·
Registered
Joined
·
4 Posts
So I made the mistake of thinking this engine only has 1 knock sensor - I was incorrect.

I replaced the knock sensor, torqued it to 17 ft-lbs and went for a drive...noticed that I still had the bog as it warmed up. :unsure:
So upon more digging, I realized that the FB20D has 2 knock sensors - 1 for each bank. Shoulda looked into it more thoroughly!
The driver's side one is easy enough to get at with a socket extension - the passenger side, not at all.
Clearly the driver's side knock sensor was not the problem.
Both are under the intake manifold and mount directly to the engine block.


I'll leave that for the dealership to troubleshoot further, but I'm not giving up on getting this solved!
HELL yeah bruv!! I don’t have an XV but I have a 2018 MT Impreza with the exact same issues described in this thread. Knock sensor sounds like our best bet thus far. The loss of power is getting REALLY bad now that the weather is getting warm again. Please let us know when you get that second knock sensor in! Do you know if the Impreza Hatch also has 2? I think both vehicles have the same motor but I’m just making sure.

You got this man, I believe in you 100%
 

·
Registered
Joined
·
1 Posts
So I made the mistake of thinking this engine only has 1 knock sensor - I was incorrect.

I replaced the knock sensor, torqued it to 17 ft-lbs and went for a drive...noticed that I still had the bog as it warmed up. :unsure:
So upon more digging, I realized that the FB20D has 2 knock sensors - 1 for each bank. Shoulda looked into it more thoroughly!
The driver's side one is easy enough to get at with a socket extension - the passenger side, not at all.
Clearly the driver's side knock sensor was not the problem.
Both are under the intake manifold and mount directly to the engine block.


I'll leave that for the dealership to troubleshoot further, but I'm not giving up on getting this solved!
Same issue with an '18 MT Crosstrek. Any resolution to this with the knock sensor swap? I have noticed as previously mentioned by someone else, if my oil level is close to the full indicator on the dipstick, the problem is much worse. Lowering my oil level to midway between the two dipstick marks seems to make it better, but not go away completely.
 

·
Registered
Joined
·
24 Posts
Hello all,

Sorry that I haven’t been able to provide any updates on the group because of personal health. Wish it was me continuing to help, but just need to wait for now.
Hoping that someone else here will be able to report that a dealer completed repair/update/fix/etc. or Subaru stepping to fix this for us. The running lack of power under load at times that we experience has not gone away, even if it’s a programming issue. A dealer NEEDS to take the time to confirm it. Still like the car when it’s a good car most of the time. Best of lock all.

Adam
 

·
Registered
Joined
·
2 Posts
Hi guys, just chiming in to say I have exactly the same issue with my 2017 5 spd Impreza with the same engine... runs fine when cool but after warming up, or if restarting hot after a 15-20min drive, especially when it’s hot out I get loss of power and stumbling around 2k-3k rpm... OBDII reader shows ignition timing being pulled when it happens. Don’t have the recalls done yet as dealer siding have any spots available until September but have little faith that it will change anything. Over sensitive knock sensors are what I suspect because others are mentioning that running higher octane doesn’t change anything... kind of disappointed in my purchase honestly...
 

·
Premium Member
Joined
·
37 Posts
Discussion Starter #67
An update. As the original poster. I have been dealing with this for a while. Thought it was solved last Jan when Tucson Subaru said the knock sensor R&R helped out a Forester with the same no power issue. Up till today the car has been doing better.

Was driving from Portland back to Walla Walla on I84 with a good tail wind & mid 70's temps. Stopped at a rest area. Upon trying to accelerate up to speed. The low power happened again. But with one additional thing. It started to hesitate while accelerating. Then after stopping at a drive thru for a bite. When I crossed the river I was on a small incline on a bridge (2% on GPS) It was hesitating badly and I was having trouble maintaining 40-45 in 3-4th gear. I stopped and thought of calling for a flatbed it was so bad. After eating. I tried again. It was better but still not running well. It would hesitate and lose power randomly for the remainder of the trip. Probably 15-20 times.

I drove 2 more hours to the selling Subaru dealer. And I unceremoniously unloaded on them. Car is scheduled for an extended stay with a long term loaner (I hope it isn't a Subaru) this time to facilitate them driving the car everyday in hopes of the issue repeating.

If they are able to fix it. Then the Subaru is going away and I will buy a real car. In my 62 years on the planet. This has been the worst new car experience. I gave up a nice Mercedes GLK250 Diesel for this headache of a Subaru because I can tow the Subaru behind our motor home. And the Subaru techs are nearly as bad as the car, What with their attitude of just shrugging their shoulders and saying, No CEL no problem. I will never buy another Subaru.
 

·
Registered
Joined
·
2 Posts
Here is something I have found that seems to clear the problem, at least for a while on my Impreza. I was having the loss of power quite bad on almost every hot day on 87 or on 91 octane. What I suspect is that on 87 octane it must knock a bit because of the high compression and I suspect the ECU learns which conditions cause knock (combination of intake air temperature, engine load etc.) and when theses conditions happens it pulls timing resulting in loss of power. (Look at this page for a review of Subaru knock monitoring from Cobb, mostly about turboed Subarus but I guess the lgorithm must be similar on NA ones too : COBB Support)

What I did was I filled up with 91 octane and reset the ECU to clear the knock conditions it had learnt. The did the idle relearn described here :
. Since then, I haven't had the problem in almost 2 weeks including very hot weather, and I was getting it almost daily before. I will try going back to 89 octane on next tank to see if it comes back. Maybe I will just have to run 91 in summer also...
 

·
Prefers non-orange cars
'18 and '19 Crosstrek Limiteds
Joined
·
10,158 Posts
An update. As the original poster. I have been dealing with this for a while. Thought it was solved last Jan when Tucson Subaru said the knock sensor R&R helped out a Forester with the same no power issue. Up till today the car has been doing better.

Was driving from Portland back to Walla Walla on I84 with a good tail wind & mid 70's temps. Stopped at a rest area. Upon trying to accelerate up to speed. The low power happened again. But with one additional thing. It started to hesitate while accelerating. Then after stopping at a drive thru for a bite. When I crossed the river I was on a small incline on a bridge (2% on GPS) It was hesitating badly and I was having trouble maintaining 40-45 in 3-4th gear. I stopped and thought of calling for a flatbed it was so bad. After eating. I tried again. It was better but still not running well. It would hesitate and lose power randomly for the remainder of the trip. Probably 15-20 times.

I drove 2 more hours to the selling Subaru dealer. And I unceremoniously unloaded on them. Car is scheduled for an extended stay with a long term loaner (I hope it isn't a Subaru) this time to facilitate them driving the car everyday in hopes of the issue repeating.

If they are able to fix it. Then the Subaru is going away and I will buy a real car. In my 62 years on the planet. This has been the worst new car experience. I gave up a nice Mercedes GLK250 Diesel for this headache of a Subaru because I can tow the Subaru behind our motor home. And the Subaru techs are nearly as bad as the car, What with their attitude of just shrugging their shoulders and saying, No CEL no problem. I will never buy another Subaru.
Sorry you've had such a bad experience. We're new to Subaru (actually, not that new any more LOL) and have been very pleased with it so far. I was concerned about lack of power from what I'd read in the automotive press but found it was just fine on a test drive. Your issue is different, of course. I wonder if there are any lemon laws where you live that could help you out? Even just suggesting to SOA that you might go that route could help. It does seem you have a very unusual case as, otherwise, Subaru seems to enjoy high customer satisfaction and high reliability ratings compared to most brands.

I have the same issue. any weather over 80 and my car just has no power, gets even worse at altitude.

I was up at 10k feet, 95 degrees and I could barely even accelerate enough to maintain 50mph. Any hill, or slight incline and I would have to be in third gear to maintain speed.

I’m to the point of selling :(
This is a different issue. Any normally aspirated car would see a drop in power at 10K and 80 degrees. Warm air at at high elevation is much thinner so less oxygen to burn fuel. I've experienced that sluggishness at over 10K in the Sierras in the summer. A turbo would help in that situation.

There continues to be a lot of criticism of lack of power, so will be interesting to see how the sales figures for the new 2.5l will compare to the 2.0l. Now that the average car buyer has a choice, will they still buy the 2.0l? In the UK and Europe, the 2.0l is the power upgrade (compared to the 1.6l).
 

·
Prefers non-orange cars
'18 and '19 Crosstrek Limiteds
Joined
·
10,158 Posts
It is and it isn’t, I’ve owned plenty of NA cars over the years and brought them the same places and altitudes and never experienced such a drastic drop in power. And when you live in a high altitude, like I do... what does it matter? Subaru doesn’t say anything about “hey yo only buy this car if you live and drive at sea level”

Not to mention the behavior is very similar to when not at super high altitudes. It acts like something is wrong, not just a change in the amount of air available, it stumbles, it feels scary low on power, like a freaking 50cc scooter feels when trying a large hill.

Either way I’m out, I’ve listed the car for sale and I won’t be buying another Subaru. I love love this car to death other than this issue, but it’s becoming a huge issue for me as I actually like to enjoy my car off-road and in high altitude situations... sadly this car can’t keep up with my needs.

And I know factually my na replacement will drive just fine at high altitudes.... this is a crosstrek issue plain and simple.
Well, I've had the same issue with other NA cars and planes. It's simple physics.

Good luck with your next car. If I lived at a high elevation I'd be looking at turbos or superchargers. Or electric, LOL, they don't care how thin the air is. Just ask Elon... 😸
 

·
Registered
Joined
·
67 Posts
Well, I've had the same issue with other NA cars and planes. It's simple physics.

Good luck with your next car. If I lived at a high elevation I'd be looking at turbos or superchargers. Or electric, LOL, they don't care how thin the air is. Just ask Elon...
You may have had issues, but you may not be experiencing the issues some of us are. This isn’t a normal low on power situation...

I’m not sure you have felt what some of us feel constantly.

I’m a car person, I’ve owned over 30 unique vehicles over the years, I build motors, I understand how they work and why. Defending Subaru, claiming this is a normal issue and simply physics isn’t correct.

Believe me or not, this isn’t normal behavior, this isn’t normal lower loss, this isn’t heat soak, this isn’t someone not knowing how to drive a stick, this isn’t anything normal.

And with how wide spread the complaints are, maybe just maybe you can admit that this isn’t normal or acceptable. The fall on your face, refuse to accelerate flat out 5hp feeling events aren’t normal for a modern vehicle.
 

·
Prefers non-orange cars
'18 and '19 Crosstrek Limiteds
Joined
·
10,158 Posts
I disagree that the complaints are widespread. If you're referring to what you read on forums like this, they are highly skewed because many more people like to go to a forum to solve a problem or vent than those who visit the same forum to say they don't have any problems with their car. In my experience it's normal for NA vehicles to have less power at high elevations and more so when it's unusually warm. We had a long thread on this (i.e. density altitude). That's the point I was making. Is that acceptable? Well, that's highly subjective. I'd say the Crosstrek has adequate power for our needs so, yes acceptable. You don't think it's acceptable and that's fine. I sincerely hope you enjoy whatever you get next...
 

·
Registered
Joined
·
67 Posts
I disagree that the complaints are widespread. If you're referring to what you read on forums like this, they are highly skewed because many more people like to go to a forum to solve a problem or vent than those who visit the same forum to say they don't have any problems with their car. In my experience it's normal for NA vehicles to have less power at high elevations and more so when it's unusually warm. We had a long thread on this (i.e. density altitude). That's the point I was making. Is that acceptable? Well, that's highly subjective. I'd say the Crosstrek has adequate power for our needs so, yes acceptable. You don't think it's acceptable and that's fine. I sincerely hope you enjoy whatever you get next...
I seriously find it funny how you are unable to comprehend that you may have not experienced the issue some of us have. And that some of us are as intelligent and understand things like yourself.

This isn’t normal power loss, this isn’t normal heat related air issues. What some of us are experiencing isn’t normal or acceptable. So continue to ignore and claim it’s fine, I won’t argue with someone who refuses to listen or agree that they may not know something.

I hope for the day that you feel or experience an event like I’ve had. Your tune would change...
 

·
Prefers non-orange cars
'18 and '19 Crosstrek Limiteds
Joined
·
10,158 Posts
I seriously find it funny how you are unable to comprehend that you may have not experienced the issue some of us have. And that some of us are as intelligent and understand things like yourself.

This isn’t normal power loss, this isn’t normal heat related air issues. What some of us are experiencing isn’t normal or acceptable. So continue to ignore and claim it’s fine, I won’t argue with someone who refuses to listen or agree that they may not know something.

I hope for the day that you feel or experience an event like I’ve had. Your tune would change...
I agree that some people are experiencing an intermittent power loss problem (see my post #69 here). I was simply responding to your post where you wrote about the loss of power at altitude (not unique to the Crosstrek). If you're at a high elevation and have the intermittent power loss as well then that's a double whammy. Sorry about that.

Crosstreks have had high reliability and customer satisfaction ratings since the new gen which is what leads to me to believe they're a small number of isolated incidents. Not that they don't exist, and not ignoring the issue (every manufacturer turns out a lemon once in a while - we returned a Land Rover under California's Lemon Law and took the offer of staying with the brand and getting a deal on a Range Rover, so I've had some experience with this).
 

·
Premium Member
Joined
·
37 Posts
Discussion Starter #76 (Edited)
Hey guys. Can we get this off of how our cars drive on Mt. Everest. My issue is happening where I live and it's 1000ft ASL. The huge issue I had yesterday happened at 400FT ASL and mid 70's temps. And if one looks at the manual. There is no requirement for high octane fuel.

One thing that gets under my skin is the modern techs employed by dealers. They have ZERO ability to diagnose an issue using mechanical theory of how an engine works. To the modern dealer. If the CEL light doesn't come on to tell them whats up. They just shrug their shoulders and say that there obviously isn't a problem. I suspect that this issue is an out of range sensor/software issue that is far too eager to retard the timing. But my new added issue of hesitation throws a spanner in the works. A hesitation upon adding throttle indicates a fuel issue and not an ignition issue.
 

·
Registered
Joined
·
67 Posts
Hey guys. Can we get this off of how our cars drive on Mt. Everest. My issue is happening where I live and it's 1000ft ASL. The huge issue I had yesterday happened at 400FT ASL and mid 70's temps. And if one looks at the manual. There is no requirement for high octane fuel.
Haha we absolutely can. Sorry to hear you are experiencing the power loss issue.

There still aren’t any concrete facts or ways to workaround the issue. I’ve ran high octane premium since new, I’ve tried “blue clear” meaning no ethanol, replaced the knock sensors, purchased a new air box and removed the charcoal filter and checked everything I could think of.

This is seemingly going to be a permanent issue with these cars, so either become comfortable dropping any revs, letting it return to idle and go back to normal driving, or get a new car.

I’ve had these issues since my first week of ownership in 2018, and they haven’t issued a fix or even admitted to any issues....
 

·
Prefers non-orange cars
'18 and '19 Crosstrek Limiteds
Joined
·
10,158 Posts
Hey guys. Can we get this off of how our cars drive on Mt. Everest. My issue is happening where I live and it's 1000ft ASL. The huge issue I had yesterday happened at 400FT ASL and mid 70's temps. And if one looks at the manual. There is no requirement for high octane fuel.
Yeah, if it's happening below 7K, I agree, it has nothing to do the thin air. I think you're in Arizona, right. Do you have good Lemon Laws there?
 

·
Registered
Joined
·
673 Posts
Any possibility there might be an issue with throttle body sticking or malfunctioning?

artosa
 

·
Premium Member
Joined
·
37 Posts
Discussion Starter #80
Yeah, if it's happening below 7K, I agree, it has nothing to do the thin air. I think you're in Arizona, right. Do you have good Lemon Laws there?
We are "snowbirds" I live in Washington state and tow the Subaru with our motor home to Az. Tucson Subaru has done a few of my oil changes and the coil pack re-flash & knock sensor.
 
61 - 80 of 115 Posts
Top