Possible factory BPV/vacuum pump issue?

[joe_sonic]

New here, so sorry if I posted in the wrong place. Just redirect me and that will be enough said. Dont need thousands of trolls jumping all over me...

Anyways, I have had my car for about a month now. Have almost 1400 miles on it too. seems like here lately I have been hearing more bypass valve chatter than usual. When I first got the car it would futter lightly under moderate acceleration at low RPM (1500-2500). Now when I am accelerating, light or heavy (especially in 2nd and 3rd gear), it sounds almost like someone is shaking a tin can full of rocks. Occasionally there is a pop in addition to that that sounds like someone tapping on the motor with a wrench. Im not throwing any codes and there are no dummy lights coming on either.

Another thing I noticed was that if I turn on the air conditioner, the car absolutely bogs down. It feels like someone threw a trailer in behind me when I wasnt looking. And under moderate acceleration if I turn off the AC the car surges. You can literally feel it when the compressor pump disengages from the motor.

Any ideas about this at all? Im about to take it back to the stealership and see what they have to say about it. Im not sure if it is a vacuum or boost issue, but whatever it is, it has put some questions in my mind about a car I absolutely love. Any advice, pointers, or opinions would be welcome. Thanks

 

[Eric Smit]

I can't answer your question, but you did post this in the right place.


-Eric Smit

 

[joe_sonic]

Thought I would add one more thing. Once I hit 3k rpm the BPV snaps shut and operates like it is supposed to. Just food for your thoughts...

 

[Sonic]

I can't answer your question, but you did post this in the right place.


-Eric Smit

This. Thanks for posting correctly.

 

[SooperSonic]

I've never experienced this issue. I rarely hear the BPV. Do you have an aftermarket intake, as this may increase the turbo/BPV noise?

 

[jchasp59]

New here, so sorry if I posted in the wrong place. Just redirect me and that will be enough said. Dont need thousands of trolls jumping all over me...

Anyways, I have had my car for about a month now. Have almost 1400 miles on it too. seems like here lately I have been hearing more bypass valve chatter than usual. When I first got the car it would futter lightly under moderate acceleration at low RPM (1500-2500). Now when I am accelerating, light or heavy (especially in 2nd and 3rd gear), it sounds almost like someone is shaking a tin can full of rocks. Occasionally there is a pop in addition to that that sounds like someone tapping on the motor with a wrench. Im not throwing any codes and there are no dummy lights coming on either.

Another thing I noticed was that if I turn on the air conditioner, the car absolutely bogs down. It feels like someone threw a trailer in behind me when I wasnt looking. And under moderate acceleration if I turn off the AC the car surges. You can literally feel it when the compressor pump disengages from the motor.

Any ideas about this at all? Im about to take it back to the stealership and see what they have to say about it. Im not sure if it is a vacuum or boost issue, but whatever it is, it has put some questions in my mind about a car I absolutely love. Any advice, pointers, or opinions would be welcome. Thanks

I just bought my Sonic 1.4, LTZ HB and have only 300 miles on the odometer.
I'm not having the BPV problems you describe, but am having the same problems with the AC compressor. VERY noticeable when the compressor turns on. Big drag on the engine and a 'jerk' that I can feel and hear. It's been a years since I've had a car that I've noticed the AC compressor coming on. Fuel injection should 'idle up' and/or get 'richer' just before the AC compressor comes on to prevent this problem. Even my Fiat 500 with only 101 HP doesn't have this problem!

Would be interested to hear what your dealership has to say regarding this AC problem. Will keep my eyes (ears!) open for the BPV problem you mentioned as my Sonic accures mileage.

 

[TurboGrayLZ]

Well this is interesting I believe I have the tin can rattling noise you describe but I haven't payed much mind to it. I would like to know what the stealership says about it. I also have the same issue with the compressor coming on sometimes it is pretty bad.

 

[MrSonic]

Tin can with rocks = VVT
AC = happens to a lot of sonics/cruzs

been there done that...

 

[joe_sonic]

Tin can with rocks = VVT
AC = happens to a lot of sonics/cruzs

been there done that...

Is it something that can be fixed that you know of? Im still trying to work around my work schedule to get the thing in the shop...

 

[joe_sonic]

Well, took it in to the stealership. Apparently the AC affecting the power is the norm for those engines. Not really sure if I believe them though. Seems like the guys in that shop are not exactly "top shelf" if you know what I mean.

I took the service tech on a ride, he said it sounded like there was a little bypass valve noise, but didnt think it was anything to worry about. I wanted a second opinion. So then I took the shop foreman on a ride. He said it was fuel injector noise. Correct me if Im wrong but fuel injectors shouldnt be making noise you can hear traveling down the road? The bypass valve should also meter airflow, not snap full open/closed all the time?

Either way I have started the paperwork trail. When it becomes a serious issue I will have documentation to back it up. Im also wondering if the trifecta tune will help these issues or make them worse? Do you think if I took it to a local shop and had them diagnose it that the dealership would fix the problem? Just want to be sure everything is running at 110% before I start modding.

 

[Screamer4]

How much experience do you have with tiny engines (and turbos on small engines)?

In my experience, with Hondas, Subarus and older GM 4-bangers, you always notice that A/C compressor hit pretty hard, especially at low rpm.

 

[Graham]

I believe its the heat shield on the downpipe that rattles. Mine does it too, seems like a great reason to get the mandrel bent stainless downpipe from one of our vendors here. Its only a 1.4Liter so the AC is going to be a bit shocking, i noticed it helps to run premium and if possible, search for ethanol free stations around you and gas up there. It really makes a difference you can feel on these cars.