P0238 - time for new turbo?

Capncoke · #1 07-10-2018, 10:27 PM

Hey folks,

My 09 pathy has been running well for the past few months since I fixed the vacuum to the BCS.

Recently I have noticed that when the engine is under load and I have constant pressure on the accelerator, it seems to sometimes lose power and the speed and revs drop. Suddenly without a change in input from me the power comes back on and off we go again. During periods of low power I get black smoke from the exhaust. As soon as the power is back, the smoke stops.

Roll forward to last week - on a little trip from Sydney to Melbourne and I get an engine light come up for the first time. I checked the code - P0238 which I believe is turbo overboost. I cleared the code and drove on. During the trip this happened 4 times.
I have cleaned the intercooler about 4000km ago using a can of magic spray that my mechanic uses.

My theory is that the only thing that could cause a lack of boost and power as well as an over boost code would be sticking vanes in the turbo. Does this sound right? If so, should I look at a rebuild or replacement of the turbo?

I don’t have a scan tool btw.

Thanks in advance for any advice.

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ericcs · #2 08-10-2018, 10:59 PM

get an OBD2 wireless reader of ebay for $10 and download the torque app. on your smart phone. you can then set the screen to show a large boost gauge, which is very easy to monitor!

Capncoke · #3 09-10-2018, 02:28 AM

Quote:

Originally Posted by ericcs

get an OBD2 wireless reader of ebay for $10 and download the torque app. on your smart phone. you can then set the screen to show a large boost gauge, which is very easy to monitor!

Any particular OBD2 scanner you know works on an iphone? Or are they all generic.

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ericcs · #4 09-10-2018, 03:20 AM

scanners are generic, but i believe they only work on smart phones, not Iphones unfortunately!

bods · #5 09-10-2018, 07:11 AM

You can get a wifi one that will work on an iPhone just not the Bluetooth ones. How much more expensive the wifi ones are though, I'm not sure. Just punch in iPhone OBD2 adaptor into eBay and it should give you an idea.

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Capncoke · #6 09-10-2018, 08:06 AM

Thanks @ericcs and @bods for the info. I’ll hit eBay and have a look.

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Capncoke · #7 14-01-2019, 12:32 PM

Ok so finally got an obd dongle and have found that my idle fuel pressure fluctuates between 4000 and 4800 psi. Does this seem excessive? SCV perhaps?

Also, turbo boost seems slow to come on under throttle and gets up to about 21psi. On a long hill, boost gradually drops off and I get black smoke and not much power. Lifting off the loud pedal and then getting on it again gives me boost again and power and the smoke goes away.

How do I tell if the drop in boost is caused by vacuum leak/faulty BCS or faulty turbo?

Also, I don’t see any EGT readings - is this normal for an 09 Spain built diesel pathy or a symptom of me not paying for a paid version of an app?

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GunMentalGrey · #8 15-01-2019, 05:02 AM

In having trouble with my 07 D40 I relaced the SCV thinking it was the issue, but found in the end it was probably the fuel primer bulb which had perished and split. It was leaking. The actual shot one see more like a misfire than low power, but it’s something else to look for. Mine was actually leaking fuel while the engine was running or when I primed it, but was probably sucking air as well.

Old.Tony · #9 15-01-2019, 11:55 AM

Capncoke, the 09 D40/R51s don't have EGT sensors so don't worry about that.

Fuel rail pressure sounds good, boost peak sounds good, but loss of boost means there's a problem and chances are in this case it's the BCS.

The way to test it (and you MUST be careful to heed the warning below) is to pop the vacuum hose that comes over from the right hand side of the engine off the BCS and connect it directly to the vacuum actuator on the turbocharger. Take it for a drive and GENTLY apply throttle.

WARNING: decelerate slowly, do NOT just drop your foot off the accelerator, the overboosting can cause trouble with the intercooler and/or the piping between the turbocharger and the intake manifold.

This is because in a variable vane turbo, there's no waste gate or blow-off valve, overpressure isn't supposed to happen, but with the turbo actuator directly connected to the vacuum pump it will pull the vanes fully open and you'll have maximum boost. If you suddenly let go of the accelerator, the throttle valve closes and the turbo is still running hard, ramping up the pressure in the system. It may pop a hose (my intercooler-to-manifold hose pops off at the manifold).

That will tell you if it's BCS or turbocharger.

If it's BCS, you can either replace the BCS with another, or get a Dawes/Tilix valve. I chose a Tilix valve for mine.

Capncoke · #10 17-01-2019, 09:28 PM

Thanks Tony for the detailed response.

Before I do the test, I just wanted to check a couple of things.

When you say a gentle drive - can I change gears (have a manual car) or do I stay in 1st/2nd when I pull off?

How much (little) throttle should I use - less than 50%, 25% etc?

Should I drive up hill for the test and monitor boost to see if it stays on or drops off?

Cheers

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