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Discussion Starter #1
I’ve had a few problems with this car and only had it a couple weeks now. I think I’ve narrowed it down to just a turbo problem..

2010 Insignia 2.0 diesel manual A20DTH.

I keep getting the overboost code. Usually at high speed but it has happened at low. Typically when going round a big roundabout in 2nd then when I come off and put my foot down, I get limp mode and SVS. I also hear the turbo ‘waste’ at low speeds, it’s like it failed to engage but when I do put my foot down it works again.

So far the cars had:
*new inlet hose (the one that commonly splits) - prev owner
*new control solenoid - previous owner.
*MAP sensor clean
*MAF sensor clean
*EGR & pipe clean
*throttle body clean

I’ve just ordered a vacuum pump to start testing. Can anyone give me some pointers with this please?
What do I need to test, where do I connect it and what should I be seeing?

thanks in advance
 

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Pull the vac pipe off the turbo actuator to test the pump, reverse if you want to pull actuator.
That would be my thinking, but I don’t have one.

High chance your problem is the actuator itself, there is a sensor on it that flags if out of range and hence over or under boost.
 

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Discussion Starter #3
Thank you.

So I plug my vac tester into the actuated pipe (out) and after, connect vac tester to actuator (in)? what should the reading be?
 

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You are testing the pump is strong enough first (sorry don’t know what it should be.)

Then switch to other side and pull the actuator and see if a reading incase actuator has a leak.

Could be because turbo arm is sticking, so clean turbo with a soak spray and oil the arm.
Or the actuator sensor itself with a fault.
 

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You should be getting minimum 25 inHg at idle at both the vacuum supply to the control solenoid and if its not in limp mode the same on the supply from solenoid to actuator.
Where did the replacement solenoid come from, is it a genuine solenoid or a cheapy from ebay/ECP.
 

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Discussion Starter #6
Hi Andy,

Thank you for getting back to me.
I’m with my car now and I’ve literally just tested. Vacuum to the solenoid is good. I’ve also plugged vac anywhere I could and all seems good.

The new solenoid was a cheap one from eBay I believe. How do I test this? At idle, my vac pump can’t hold the vac going into the solenoid, is this normal? The actuator stays down at idle under the normal engine vacuum. And the actuator arm and wastegate seems to be moving freely and normal when activated manually.
 

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What do you mean by cant hold the vacuum, are you supplying the vacuum to the solenoid with your pump or are you plumbed inline with the cars supply.
 

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Discussion Starter #8
I was supplying vacuum to the solenoid with my pump.

When at 1k revs above, I can see the actuator arm moving up and down. Is this normal? Like it won’t stay up when revs applied
 

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Yes thats normal, it wont make boost while revving it at standstill so the actuator is adjusting the wastegate to bleed the boost off, do you have Opcom, if you do then record some live data while making it go into limp mode and post it here.
With the engine at idle the control solenoid will pull the actuator all the way down putting the turbo into full boost, this si to provide enough boost for you to accelerate away from standstill, it will then constantly adjust the actuator while your driving according to throttle input, if its overboosting then there are two reasons why this can happen, the control solenoid is sticking and not dumping the vacuum quick enough or the wastegate is sticking, to test the vacuum scenario you would need to plumb your test gauge into the vacuum line on the actuator side of the solenoid using enough silicone hose so you can see the gauge inside the car, if the vacuum is dumping off but its still going into limp the the wastegate is sticking, if the vacuum dont bleed off when it should then the solenoid is no good, vacuum should always disperse at throttle off to dump boost.
 

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Discussion Starter #10
My op-com isn’t letting me record live data for some reason. I can view the measuring blocks live though.

In terms of testing the dump, can I do this in neutral, without driving? And just so I’m clear, put my vac tester in between solenoid and waste gate or connect just to solenoid? I have someone here with me so I can view the gage no problem.
Sorry, I’m new to turbos
 

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You need the gauge between solenoid and actuator and it needs testing while driving, so needs monitoring from inside the car, you wont get it to go into limp unless your driving and at the point it goes into limp you need to see if the vacuum has dumped off, if its still holding full vacuum this will explain why its going into limp, you could, if you knew what to look for, compare it to the control solenoid PWM signal.
 

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Discussion Starter #12
Ah right I get it now. I’ll need to get some more pipe first though. Is the wastegate a serviceable part? Can it be replaced or is it integrated with the turbo?
I’m not sure what pwm signal would be or even if I have the software to read it
 

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Discussion Starter #13
Update*

So today I did some tests.
With a friend we rigged up the vacuum pump to create a boost gage that we could monitor when driving.
Everything was performing as we think it should and everything seemed consistent. I tried to get the car into limp mode but it didn’t happen. I tried low speed and high speed for quite some time but no limp mode.

So this seems like it is more intermittent than I first thought.. and it makes me think that it could be due to something sticking rather than a failed component. Perhaps the turbo vanes?

when I get the time, I will clean the turbo vanes and see if that helps. is this as straight forward as I think it is to do? Also, could I just spray some wd40 down the actuator arm to help with a possible sticky spring on there?

Any help, guide or pictures to assist with this job please?
 

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You can try spraying WD40 on the spindle that goes into the turbo, which might help.
If it's the vanes sticking, they are in the exhaust side of the turbo, so spraying anything into the inlet side of the turbo is a waste of time.
On my old Seat Toledo (VW 1.9TDI engine), I was able to remove the EGR valve, and sprayed lots of Mr Muscle oven cleaner down the pipe to fill the exhaust side of the turbo. I let it soak, then used a Mityvac to work the actuator until it all freed up. When re-assembled, it cured my overboost problem, which didn't return in the five years or so I kept the car!
I don't know if you could do this on your car.
 

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Discussion Starter #15
With mine the turbo is right at the front of the engine and the EGR is at the back. I think it will be easier to take it off for a proper clean, that way I know for sure it’s not sticking.
 

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Buy some turbo cleaner to add to your fuel then go get it nice and hot, this should clean any excess carbon from the vanes.
 

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Discussion Starter #17
Does it sound like a sticky vane problem to you Andy?
Is it not worth taking the whole turbo off then?
 

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It could be, funny why its corrected itself while you have been messing with it, this would suggest its sticky vanes, removing the turbo to strip it for cleaning is up to you, only you know what your capable of doing in a mechanical capacity, if your comfortable doing it, it is the better way to clean it.
 

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Discussion Starter #19
Yeah I find it strange too. I did put some redex in the fuel last time I filled up, after the big clean and I haven’t really driven it until that test. So maybe that’s helping?

I’ve almost got the turbo off but I’ve given up for tonight. I’ve got all the bolts off and loosened the DPF clamp but the thing won’t wiggle free! The turbo is sat on at least one stud from exhaust manifold so I feel like I need to get that clamp away, to then lift the turbo up and off. If that makes sense?
 

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Discussion Starter #20
Scratch that. The turbo is off!!! Didn’t realise the stud was removable 😆

Now to split it and clean. Let’s hope the car lords watching over me 😬
 
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