Doblo 1.3 MJD reporting P0238 (low boost), no power on hills and lots of black smoke when accellerating.

MAF changed no effect
MAP changed no effect
ERG blanked no effect
Turbo removed and verified OK.
Turbo boost solenoid replaced no effect.
Crack on exhaust manifold fixed - no effect.

Desired boost v actual boost shows actual boost is consistenly 200mBar lower than the desired boost.

Turbo has beened replaced approx 18 months ago.

I suspect that the boost actuator needs to be shortened to increase boost. Has anyone tried this or am I delusional in thinking this will help.

Spanner12 said:

Doblo 1.3 MJD reporting P0238 (low boost), no power on hills and lots of black smoke when accellerating.

MAF changed no effect
MAP changed no effect
ERG blanked no effect
Turbo removed and verified OK.
Turbo boost solenoid replaced no effect.
Crack on exhaust manifold fixed - no effect.

Desired boost v actual boost shows actual boost is consistenly 200mBar lower than the desired boost.

Turbo has beened replaced approx 18 months ago.

I suspect that the boost actuator needs to be shortened to increase boost. Has anyone tried this or am I delusional in thinking this will help.

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I'd have suggested a leak too,
SEARCH in panda section for that code.. lots more 1.3D traffic in there,
Charlie

I have had the car to 2 different mechanics a number of times and they has guaranteed me that there was leak. So I have ruled that out as possibility

When I plotted desired boost versus actual boost you could see that the actual was tracking the desired boost across the a range of rpm from 1.5k to 3.5k (there were no unusual spikes or dips). However the boost was always low. My theory is that the turbo actuator has been calibrated badly when the turbo was replaced and by shortened the rod it will shift the actual boost closer to the desired boost.

My thoughts was the shorted it by maybe 1 turn and re-collect the desired v actual boost data. If the actual boost is closer to the desired boost then continue adjusting until I get the two to match.

Spanner12 said:

I have had the car to 2 different mechanics a number of times and they has guaranteed me that there was leak. So I have ruled that out as possibility

When I plotted desired boost versus actual boost you could see that the actual was tracking the desired boost across the a range of rpm from 1.5k to 3.5k (there were no unusual spikes or dips). However the boost was always low. My theory is that the turbo actuator has been calibrated badly when the turbo was replaced and by shortened the rod it will shift the actual boost closer to the desired boost.

My thoughts was the shorted it by maybe 1 turn and re-collect the desired v actual boost data. If the actual boost is closer to the desired boost then continue adjusting until I get the two to match.

Click to expand...

I can't promis this is feasible because I've not done it on a 1.3, but you might find it easier to fit a bleed kit and dial in what you want. The fable is that these lead to lag, which is correct in theory, but it's minescule, and down to how long the pipe runs are (eg if you fitted it right by the turbo you'd get none) but in your situation if it added shed loads of lag (which they don't, honestly) it would be an improvement anyway.

They're about £20 or less on fleabay, plus you'll need some joiners and ties to secure and hose (generally 4mm silicone is supposed to be best,but anything that has a ridged wall works)

Go sensible and you should be OK turning it up until the fault disappears - or fit a guage.

I assume to bleed kit is a brake bleed kit with a vacuum gauge on it. I might just get the mechanic to do this. Is this something that a general shop would do or do I need to go to a specialist?

Spanner12 said:

I assume to bleed kit is a brake bleed kit with a vacuum gauge on it. I might just get the mechanic to do this. Is this something that a general shop would do or do I need to go to a specialist?

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It's a valve that goes between the turbo and the turbo boost valve which delays the wastegate opening, and so increases boost and power - when done in conjunction with eg a chip that over pressures the fuel etc.
In your case it would get around the adjustment problem you've got (it sounds a viable cause - unless it's a non-adjustable arm in which case somebody fitted the wrong turbo).

I *assume* that all your sensors have been cleaned? That the boost valve has been checked out? They can clog - particularly on the exhaust port and give problems.

Don't take this the wrong way, it's not meant to sound smug / sh*tty whatever - but it's probably not what you want if you don't know what it is

They are a viable way of upping output but it's not something you want to go into blind or using guesswork, and I doubt if any mechanic would fit one for you because if he screws up your engine (which he could by being careless) you'd have his guts for garters

Thanks for the clarification. I wasn't sure what the valve was supposed to do, it might just do the trick.
All the senors have been cleaned and/or swapped for known good parts. The boost valve has been replaced. Turbo was removed and verified good by a re-conditioner. I am kinda going with the Sherlock Holmes theory here, eliminate all that is possible and whatever is left no matter how improbable is the solution.
One question on the in the in-line valve - will the max boost be limited by the actuator rod or will i get the full range boost?

Spanner12 said:

Thanks for the clarification. I wasn't sure what the valve was supposed to do, it might just do the trick.
All the senors have been cleaned and/or swapped for known good parts. The boost valve has been replaced. Turbo was removed and verified good by a re-conditioner. I am kinda going with the Sherlock Holmes theory here, eliminate all that is possible and whatever is left no matter how improbable is the solution.
One question on the in the in-line valve - will the max boost be limited by the actuator rod or will i get the full range boost?

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Image that as you rev the engine you bring in boost.

At 2K revs you bring in .5 bar

At 2K revs the wastegate opens 10%

At 3K revs you bring in 1 bar

At 3K revs the wastegate opens 80%

At 3500 revs bring in 1.2 bar

At 3500 revs wastegate opens 100%

At 4K revs you bring in 1.2 bar

At 4K revs the wastgate is 100%, limiting the boost to 1.2 bar

^ this is a BIG over-simplification.

The wastegate is opened by pressure from the boost valve as revs increase.

If you bleed some pressure between the boost valve and the wastgate, you allow more boost to occur before the wastegate limits it. Bleed too much and wastegate doesnt open, but top of engine does

^ all oversimplified, but thats what it's about.

Is there a sensor on the back of the 1.3, into the inlet manifold? Right at the back, has a lead plugged into it and is held by one bolt. If so, have you had it out and cleaned it out with brake cleaner? (dont stick anything inside it)

The MAP sensor has been cleaned and swapped for a known good part. MAP records low actual boost and the MAF is indicating low airflow.

Nice explanation of the turbo operation, I keep forgetting that no vacuum equals max boost, so I am going to get an in-line valve and give it a try.

Thank for your assistance.

It's what we're here for BUT do read up on them before getting one and fitting it, and don't do it without a boost gauge fitted. Google like stink and read like stink too - engines is expensive
(If you put boost gauge into search you should throw up some how to's - theres a few ways of doing it)

I ordered the boost controller, can I use the MAP reading to play around with the setting or do I need an external boost gauge.
I guess I have few days for research before the controller arrives (the only problem with google is figuring who to believe). Fingers crossed - this will sort out my turbo issue. I will report back when it is installed

Spanner12 said:

I ordered the boost controller, can I use the MAP reading to play around with the setting or do I need an external boost gauge.
I guess I have few days for research before the controller arrives (the only problem with google is figuring who to believe). Fingers crossed - this will sort out my turbo issue. I will report back when it is installed

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I wouldn't fit one without fitting a boost gauge, even if only temporarily hanging it on the dashboard while adjusting stuff.
Seriously.
Very bad ju-ju...

And shut the boost controller right down, then adjust **VERY F***ING GRADUALLY** and read the boost gauge under load, not sitting in your garden
This is why it's better to stick the controller in the cab somewhere, so you can do it on the hoof, even if it marginally / mythically lags on longer runs. The run into a Dob cab is less than a metre even if you route it around the houses...

I will try to find the step-by-step of fitting a boost gauge I did a while back for you. It might be different on yours, but it will give you the basic idea.

I got the boost controller and did a lot of research on the Tinternet. Unfortunately it left me more confused than when I started. The 1.3 MJD is not a waste gate type turbo, it is controlled directly by the ECU by the boost solenoid so I could not see how bleeding some of the vacuum was going to increase the boost. I did a basic test by removing the vacuum line from the turbo. My assumption was that I had max boost with no vacuum. I guess I was wrong - no boost at all across all rpm's. Since no vacuum equals no boost fitting the bleed valve could only reduce boost not increase it.
I also put a vacuum gauge on the house vacuum and the vacuum going to the turbo. Both looked OK. I also manually checked the turbo actuator was moving the full range at the correct vacuum level. I also got my hands on another MAF, still no improving. Dobby is smoking like a chimney and no boost.
Looking at the data coming back from the MAF and MAP I can only assume I am loosing boost somewhere i.e. MAF air flow consistent with a working turbo and the MAP indicating low boost. I am going to recheck the pipes from the turbo to the inlet manifold.

I spent a hour this afternoon looking at all the turbo pipes to and from the turbo. Everything looked OK, however just as I was about to close the bonnet I noticed that the chassis behind the EGR was very black. I thought this is all I need and oil leak but the consistency of the black gunk was not of engine oil. Anyway I felt around the pipes in the general area and guess what a gash on the underside of the turbo pipe from the intake manifold.
Taped it up with some duct tape as best I could and put a couple of cable ties to hold it together. Took it for a test drive and I have power again. A bit noisy as I am still leaking boost. Ordered a new pipe from the local spares guys and I should have it tomorrow.
A bit annoyed that the two mechanics did not find this, all the data coming from the car was showing boost loss, it won't have taken 30 mins to remove all the pipes to and from the turbo and give them a proper inspection. Hindsight is a wonderful thing!
Main thing is my car is back to its old self at long last.

Excellent job

Hope you get your money back from the mechanics!!

Mondeo TDCi engines are well known for just this problem, but being a larger engine, the power loss isn't as noticeable. The loud hiss under acceleration and initial roll-off is the clue on these engines

(Yes, I did have one!)

Mike

New pipe fitted this evening - power levels back to normal. Happy days.