# Valves in the exhaust system?



## JordanNaylor (Feb 3, 2013)

Annoyingly I have to keep my cruze for longer, so I might as well keep trying to get it fixed (look at my other posts about the sluggish engine/drive)

I was speaking to my Auntie the other day and it came up in conversation, and she had a very similar issue with her Honda CR-V (totally different car I know) but very very similar symptoms with intermittant sluggish drive, lack of power and lumpy power delivery. It was eventually narrowed down to a valve in the exhaust which was sorted after a recall of all the models. 

Are there any valves in the Cruze exhaust system that could cause this?

Even if I could just unplug it or remove a section of the exhaust to eliminate it and see if it still has the same issue?


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## spacedout (Dec 7, 2010)

From the motor to the tail pipe there is nothing that moves. When someone mentions an exhaust valve, this part is inside the engine, more specially the head. Every engine/head has intake and exhaust valves, in time with the engines piston movements open and close to bring air into and out of the cylinder. 

My guess though if there was an exaust valve issue with your car there would be some kind of check engine code and it would run rough.


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## spacedout (Dec 7, 2010)

Curious what is the power output of the 1.6L in your car? can imagine its pretty low, wonder if your intermittent low power issues are caused when you use the AC?


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## 2013LT (Jul 3, 2013)

The valves are located in the cylinder head. If they fail to open I imagine you'd get a misfire which would throw a CEL. What have you done to try and resolve the loss of power? Are there any check engine lights on?


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## jblackburn (Apr 14, 2012)

The only thing that I'm aware of with the 2008-2010 2.4L Honda motors was a flaw in the variable timing system and/or piston rings that caused the engines to burn lots of oil (sometimes causing fouled spark plugs and smoke from the exhaust).

The Cruze's engine is a completely different design and any hesitation you are getting stems from a different cause.

If it's burning oil, some 2011-early 2012 engines have been replaced due to faulty piston rings. Hesitation with 2011 automatic transmissions is common, and "hesitation" on 2012-13 models is common on low octane gas and improperly gapped spark plugs. If you have not tried either of these, try it.


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## haoleboy (May 9, 2012)

I'm curious about what kind of power you expected to get from a 1.6l N/A motor? Were you mislead and didn't know you were buying a 4cyl econo-box?


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## spacedout (Dec 7, 2010)

So I looked up the UK 1.6L(non-turbo), looks like its 122HP(91KW)@ 6200RPM & 114lb-ft torque(155NM) @ 4,000RPM. WOW, and I thought our 1.8L was low on power!


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## jblackburn (Apr 14, 2012)

spacedout said:


> So I looked up the UK 1.6L(non-turbo), looks like its 122HP(91KW)@ 6200RPM & 114lb-ft torque(155NM) @ 4,000RPM. WOW, and I thought our 1.8L was low on power!


Wouldn't be so bad if the Cruze wasn't 3100 lbs. ~115-125 HP was pretty standard for 4-cyl cars 10-15 years ago (usually >2 liters too), but they were much lighter.


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## spacedout (Dec 7, 2010)

jblackburn said:


> Wouldn't be so bad if the Cruze wasn't 3100 lbs.


That's exactly what I was thinking.


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## JordanNaylor (Feb 3, 2013)

Its not too bad when its working correctly, although I've not had many more powerful cars (besides my 1.8 Vauxhall Vectra) but its not much slower than that. Mine (annoyingly) is the lower powered 1.6, they do the 124Bhp version, and the 111BHp one which mine is. In the UK though, with lots of bumpy thin windy roads you don't need much more power to have fun before you start creating parking spaces in bushes and trees. 

But no warning lights, the catalytic converter obliterated itself about a month ago and was replaced under warranty, its had new knock sensor, new coil pack and some other small bits (forgot what they are now) but nothing has solved the issue. Even when the catalytic converter went it didn't show any codes.

I'm thinking it could possibly be an O2 sensor of sorts. MPG isn't doing brilliantly either (its not too bad when its running properly) 

The day I do an engine swap for a 2.0 Turbo from the Vauxhall Astra VXR will be a good one!


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## jblackburn (Apr 14, 2012)

Have they tried a new mass airflow sensor? Intermittent power loss was always a common symptom of MAF failures on my older cars.

For instance, this sounds kinda like what you're experiencing.
http://www.matthewsvolvosite.com/forums/viewtopic.php?f=1&t=58177&p=295613#p295613


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## JordanNaylor (Feb 3, 2013)

jblackburn said:


> Have they tried a new mass airflow sensor? Intermittent power loss was always a common symptom of MAF failures on my older cars.
> 
> For instance, this sounds kinda like what you're experiencing.
> http://www.matthewsvolvosite.com/forums/viewtopic.php?f=1&t=58177&p=295613#p295613


I did think that this could be an issue, and after having a POD filter on the car for a few months after I bought it (Petrol was getting expensive as I liked the sound when It was at full throttle) this could have set this off (bar the fact that this issue was present before the POD filter was added). So, last week rang up to see how much a new MAF sensor would be, i've seen them on other cars, just a small plug screwed into a pipe or something near the air intake. BUT apparantly on my cruze, the MAF sensor is built into the throttle body, which means a large strip-down to get the throttle body out, and £190 ($300~) for the new throttle body etc, and that may not even be the issue. I was expecting about £50 for the sensor and 5 or so minutes to swap out the old one for the new one. The sensor I thought was the issue and what I thought was the MAF sensor was just the intake air temperature sensor. Bit of a bummer really. 


It has actually run pretty well the last few days, earlier today it had a sluggish few drives, unplugged the post-CAT O2 sensor, made no difference, plugged it back in, drove OK but still not how it should, unplugged the pre-cat 02 sensor, ran that disconnected for about 15 miles, started to get sluggish again, plugged that back in and all seems well for now. See how long it lasts!

Another question regarding the 02 sensors: I have Torque pro and a bluetooth OBDII connector and i've set up the readout so I see what the pre and post CAT O2 sensors are reading. Post cat sensor moves up and down mostly in correlation to accelleration and throttle position ( more air flow detected I guess? ) however, the pre-cat sensor is jumping up and down all of the time. I've got them laid out on a horizontal bar graph, i guess a bit like a digital rev counter bar, and its just from minimum to maximum, minimum to 3/4, blah blah. I havent fully correlated it to the issues im having, but are they meant to do that? It was doing it when it was running poorly, but I forgot to put the app back up when I was driving home earlier when it was running OK.


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## spacedout (Dec 7, 2010)

JordanNaylor said:


> I did think that this could be an issue, and after having a POD filter on the car for a few months after I bought it (Petrol was getting expensive as I liked the sound when It was at full throttle) this could have set this off (bar the fact that this issue was present before the POD filter was added). So, last week rang up to see how much a new MAF sensor would be, i've seen them on other cars, just a small plug screwed into a pipe or something near the air intake. BUT apparantly on my cruze, the MAF sensor is built into the throttle body, which means a large strip-down to get the throttle body out, and £190 ($300~) for the new throttle body etc, and that may not even be the issue. I was expecting about £50 for the sensor and 5 or so minutes to swap out the old one for the new one. The sensor I thought was the issue and what I thought was the MAF sensor was just the intake air temperature sensor. Bit of a bummer really.


Was that Pod filter oiled? could be the MAF sensor is just getting erratic readings because its dirty. Are you sure your MAF sensor is part of the throttle body? I realize your in the UK and have a different engine but if you could post some photos of your engine/intake so others can have a look and make sure thats correct, I have never heard of a MAF sensor being mounted that way.


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## sciphi (Aug 26, 2011)

The pre-cat O2 sensor should flip back and forth about once a second or so. The post-cat O2 sensor should stay pretty flat. 

Also, removing the TB should not be that hard. It is a 4 cylinder NA engine. In the words of your own Jeremy Clarkson, how hard can it be?


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## 2013LT (Jul 3, 2013)

The catalytic converter imploding is sending warning bells in my head. Cats usually last a significant amount of time unless a few conditions are met:
1. Car is running rich
2. Car is burning oil
3. Car is misfiring
4. Car is not getting to optimal temperature
5. Timing is incorrect.

O2 sensor comes to mind, after that possibly a faulty crankshaft position sensor or camshaft position sensor (*should* throw a CEL). Check your spark plugs again and gap them properly. Check your fuel pump and anything else related to fuel and spark, including all filters. Even if you have done it recently, check it again. Check your coil packs to make sure they are allowing the proper spark to be passed onto the plug, reinstall with dialectic grease on the non spark side of the plug. Not sure if the 1.6 has a timing belt or chain but it would probably be a good idea to check and make sure nothing has slipped, if it's off by 1 tooth it will cause the car to run funny. Clean the throttle body thoroughly and make sure the coolant level is where it should be (sometimes there is a coolant passage near the throttle body that will cause erratic idle and poor acceleration if air is passing through, not sure if the Cruze is one of those cars). This is how I'd start diagnosing this anyway.


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## sciphi (Aug 26, 2011)

The 1.6 is a timing belt engine. Having the timing 1 tooth off would throw a lot of things off. The VVT would be able to correct some, but some situations would be outside its range for corrections. It might not even throw a CEL for a cam/crank sensor if those sensors were within their ranges, which has happened on other cars. 

Loosening the spark plugs and cranking the engine over by hand until the timing marks on the cam pulleys line up with the marks in the head and comparing each cam pulley is a good idea.


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## 2013LT (Jul 3, 2013)

There you go. You have a few more things to check. Your catalytic converter failing is directly related to your car not running properly. I can guarantee that. It will happen again if you don't resolve the issue.


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## 2013LT (Jul 3, 2013)

If you need any further help with this I have a ton of mechanical experience and can probably give you a hand. It wouldn't hurt to do a compression check on the cylinders as well.


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