Kyle09TC

P0238 Overboost. Need help.

33 posts in this topic

I have read plenty of dead end threads on here around this issue. Recently pulled intercooler out and patched it, but have still been getting the P0238. The car revs over 3000rpm, really struggles in 4-6th gear and loses a lot of speed on hills (don't think this is normal). There is oil in the hose from the turbo to the intercooler. I will be checking the turbine shortly to check for movement and shaft play. The wastage does move. To lower the pressure do i spin the nuts for the wastegate left or right?

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Remove the rear end and work the wastegate back and forth with a big adjustable. . my bet its gummed up and isnt opening

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Make sure it moves first, off the top of my head I dont remember the adjustment I'll have to dig in

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To lower wastegate boost pressure setting you must lower preload on wastegate actuator spring. Do this by moving adjuster nuts to the right on rod.

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I have moved the wastegate, it will open with a fair amount of pressure but seems to still open. I read to spare it with graphite spray and i have. I will move the nuts over a bit tomorrow and see if that helps any. I will also continue to work the wastegate and make sure it is opening fully.

Might be unrelated, I am getting a squealing noise from about 1800-2800 and goes away above that, not sure if its a belt or something else. Anything i should look at while i have it all apart tomorrow that may be related to this?

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Wastegate springs generally do not become stiffer over time so perhaps you should check wastegate hose for splits and leaks.

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My wastegate moves ok, I lubed it up and maybe it is a little more free, Seems like I do this every 2-3 months to keep the codes away. Could the actuator be getting bad, could not detect any leaks in it or the hoses.

anyone have intermittent problems with the sensor? And where is the sensor located?

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I find that when reading some of these post you end up hanging there waiting for the solution or no one acknowledges its fixed and by what means.

My engine light just came on today with the P0238 error code from my Scanner.

As I try to solve this problem my guess it either its a sticky waste gate valve or a possible crack in the hose effecting the performance.

Is that correct?

Mr. Ronfire asked where the sensor is located, yet there was no reply.

Is there a sensor for this mdoel or Is it that no one knows or is it no one cares to be helpful?

It can be frustrating.

 

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Boost pressure sensor sits on rubber mounts at right hand side of valve cover.  Sensor is connected to inlet manifold by a rubber hose.

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2 hours ago, Ritchie said:

Is there a sensor for this mdoel or Is it that no one knows or is it no one cares to be helpful?

It can be frustrating.

 

Do you assume that every thread will always contain all the information ?

In another topic ,I mentioned the location of this sensor, about 4 weeks ago.

I also try to post x-ref links in topics, to find related stories, that might be related.

 

You need to do more searches to find the answers, because not everybody on here is perfect.

 

Gads, I try, but I'm not either.

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On 9/8/2016 at 5:23 PM, tolsen said:

Boost pressure sensor sits on rubber mounts at right hand side of valve cover.  Sensor is connected to inlet manifold by a rubber hose.

 

Is there a way to test it?

or clean it out if it is contaminated by the failed intercooler from engine oil vapour?

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Posted (edited) · Report post

I'm still having intermittent P0238 code problem. It goes into limp mode. After a short or long drive the engine light  will come on, there is no consistant pattern that I can find, my OBDII scanner indicates this error code.

Sometimes I will clear it with the scanner and it will run fine again other times I will shut off the motor, let it sit for a while, and the engine warning light will no longer display a problem, then it runs fine again. I cannot assume it is the waste gate adjustment or the wategate hose if it is intermittent.

Why would it corrects itself or activate a code is confusing? Why would it go into limp mode? Either it is either broken or it isn't? What controls the wastegate actuator? Is it vacuum actuated or pressure? So many questions and no one to answer.

Edited by Ritchie

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Ritchie

Will your scanner show boost or map numbers while driving?  I think the maximum map should be about 2.1 bar or max boost be about 16 psi.  If you can’t get the numbers you are welcome to come up here and try my Scangauge.  I’m about  20 minutes north of 400/401.

 

Nigel

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2 hours ago, Ritchie said:

I'm still having intermittent P0238 code problem. It goes into limp mode. After a short or long drive the engine light  will come on, there is no consistant pattern that I can find, my OBDII scanner indicates this error code.

Sometimes I will clear it with the scanner and it will run fine again other times I will shut off the motor, let it sit for a while, and the engine warning light will no longer display a problem, then it runs fine again. I cannot assume it is the waste gate adjustment or the wategate hose if it is intermittent.

Why would it corrects itself or activate a code is confusing? Why would it go into limp mode? Either it is either broken or it isn't? What controls the wastegate actuator? Is it vacuum actuated or pressure? So many questions and no one to answer.

Had the same problem. i removed actuator hose cleaned it up to the sensor and it hasn't reappeared  

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6 minutes ago, GRP151 said:

Had the same problem. i removed actuator hose cleaned it up to the sensor and it hasn't reappeared  

Which sensor?  There is no sensor on waste gate actuator.

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On 9/8/2016 at 5:23 PM, tolsen said:

Boost pressure sensor sits on rubber mounts at right hand side of valve cover.  Sensor is connected to inlet manifold by a rubber hose.

 

What controls the boost pressure sensor? Pressure, vacuum, electrical?

Do you have a picture please?

TURBO.JPG

Hultafors.jpg

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Ritchie

I will try but I may not get it exactly right.  On your first picture, on the left side of the Turbo there is a hose about a quarter inch diameter going from the Turbo to the wastegate actuator.  The pressure travels through the little hose and pushes against a diaphragm and spring in the actuator and when there is enough pressure to overcome the spring the actuator rod moves the wastegate towards the open position.  As the pressure drops the spring in the actuator moves the wastegate back to the closed position.  By moving the nuts on the rod where it is attached to the wastegate lever will change the preload on the actuator spring therefore raising or lowering the maximum boost.  I don’t remember which way you would turn them left or right to lower the boost.  Since your problem is intermittent I suspect your adjustment is pretty close within a turn or two.  Also if you have a crack or hole in the little hose full boost may not be getting to the actuator and therefore not opening the wastegate and causing an over boost condition.  

 

Clear as mud?

Nigel

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Moving nuts on waste gate actuator rod to the right lowers turbo boost pressure. 

Carefully inspect hose on waste gate actuator for possible cracks or splits. 

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7 hours ago, Nigel said:

Ritchie

I will try but I may not get it exactly right.  On your first picture, on the left side of the Turbo there is a hose about a quarter inch diameter going from the Turbo to the wastegate actuator.  The pressure travels through the little hose and pushes against a diaphragm and spring in the actuator and when there is enough pressure to overcome the spring the actuator rod moves the wastegate towards the open position.  As the pressure drops the spring in the actuator moves the wastegate back to the closed position.  By moving the nuts on the rod where it is attached to the wastegate lever will change the preload on the actuator spring therefore raising or lowering the maximum boost.  I don’t remember which way you would turn them left or right to lower the boost.  Since your problem is intermittent I suspect your adjustment is pretty close within a turn or two.  Also if you have a crack or hole in the little hose full boost may not be getting to the actuator and therefore not opening the wastegate and causing an over boost condition.  

 

Clear as mud?

Nigel

 

Just so that I'm clear,

1. Air pressure is generated by the exhaust turbine which has another turbine attached to the same shaft that controls intake air that travels into the intake to create the turbo effect

2. At the same time some of the air travels into a passage way carried by the hose to a diaphram called the actuator which has a mtering rod controlling a valve called the wastegate.

3. It has fine adjustments that determine the volume of air to be exhausted through this valve, the waste gate.

 

I think what GRP151 was referring to is lubricating oil for the turbine  can accumulate from a worn turbine shaft may pollute the hose to the diaphram and restrict or change the actuators performance?

 

 

 

 

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Posted (edited) · Report post

^thats sounds about right except i wouldnt say air pressure is generated by exhaust turbine...id say the exhaust turbine is powered by the engine exhaust flow....which in turn generates pressurized intake flow

 

 

11 hours ago, Ritchie said:

 

What controls the boost pressure sensor? Pressure, vacuum, electrical?

Do you have a picture please?

 

 

 

i may be wrong but

 

 

i think the confusion is that the "boost pressure" sensor is actually a map sensor ...only used for ecm 

 

the other wastegate actuator system is completely separate pressure operated system that works on its own (no ecm involved)

Edited by LooseLugNuts

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Posted (edited) · Report post

I would then assume the wastegate's purpose is to dump excessive air pressure out of the system via the exhaust manifold to maintain the correct turbo charge depending on the RPM's?

If this is correct where is the boost pressure sensor located that would detect an overboost condition?

Somewhere in the air duct to the intake port I pressume.

 

Edited by Ritchie
typo, apparently when using Explorer as a browser here ther is no spell check!!!

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See your own post no 18. Inlet air pressure sensor sits about an inch forward of rail pressure sensor. It is connected to inlet manifold via a small diameter rubber hose. 

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On 11/20/2017 at 10:21 AM, GRP151 said:

Had the same problem. i removed actuator hose cleaned it up to the sensor and it hasn't reappeared  

 

Actuator hose had some obstruction within, oil or carbon,  Problem hasn't returned.

 

boost sensor.png

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1 hour ago, GRP151 said:

 

Actuator hose had some obstruction within, oil or carbon,  Problem hasn't returned.

 

boost sensor.png

Wrong word since that is a sensor, not an actuator. Proper description surely must be “sensor hose”.

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why post pictures of map sensor and then talk about actuator hose?,..

 

its almost like youre trying to confuse this person on purpose

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