[TheCornishOne]

Hi all, thank you in advance for any help I receive.

Long story short - I've just bought my first Alfa - a 2002 156 Sportwagon 2.4, it was a barn find (ish) by a friend of mine - it had been sat for 14months, it's recently had a fluid change and a new alternator - it's fairly clean and rust free and the interior is in mint condition with tan leather and the Bose upgrade. It has good service history has been looked after during its 120k mile life.

When I bought it I knew about the intermittent fault and thought it would be straight forward after reading a few threads on what sounded like the same thing.

So I've had it plugged in with Graham Eddy in Penzance and it came back as an over boost error.

On reading it could be a number of things.....I'm just looking for some advise really.

So this is what's happening......

On start up, drives beautifully - pulls very well and spools well - if I don't drive over 3000 revs it can stay trouble free for up to 10 miles or so if I do boot it usually in 3rd around 3000rpm I'll get the engine management light come on and power will die, if I change into 4th at this point and whilst clutch is pressed leave it long enough that the revs come down to 2500 ish the light will go off again and it'll carry on pulling but not what feels like 100% - this whole thing is more apparent if I'm going up hill??

Apparently previous owner checked hoses and I have personally done MAF sensor clean and EGR clean

I have read about turbo viens and MAP sensor and not got to these yet.

Can anyone out there help me with some knowledge they might have??
Anyone else experienced the same and fixed it?

Let me know if you need more details - I really want to sort it out so I can enjoy my first Alfa to its fullest.

Thanks again

Ross



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[_The_Editor_]

That EGR looks gunky! I'd get a blank on it to start with.... But overboost into limp mode at higher revs and when the engine is under load (up hills) does sound like sticky turbo vanes....

Get the EGR blanked up and try again! It'll probably chuck and EGR error on the dash, but it doesn't hurt anything!

 

[TheCornishOne]

That EGR looks gunky! I'd get a blank on it to start with.... But overboost into limp mode at higher revs and when the engine is under load (up hills) does sound like sticky turbo vanes....

Get the EGR blanked up and try again! It'll probably chuck and EGR error on the dash, but it doesn't hurt anything!

Thanks for your reply - is blanking the EGR an easy task? Is there a kit or is it a case of making a plate up similar to a gasket and put it in place?


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[_The_Editor_]

Yea easy job.

Get the engine cover off (3 10mm bolts), then it's just 4 bolts on the back right corner of the engine.

You can get blanking plates/kits on eBay for a few pounds.

Just be careful when putting it back together, don't over tighten the bolts though or you'll strip the threads right out of the head!

 

[FoxtrotOscar]

Blanking the egr is unlikely to help with your overboost problem; this is most often caused by sticking turbo vanes, or a damaged turbo (the tips of the turbine wheel get damaged, making it impossible to control the speed - and therefore boost level - of the turbo). In either case, the turbo needs to be removed, stripped and inspected. Considering the mileage of the car, it's quite likely that a new turbo will be required.

 

[gammakeith]

I too had intermittent over boost recently on my 20V. My problem was 100% cured by stripping and cleaning the turbo vanes. The actual turbine core was fine at 148,000 miles. The job was not too bad but the biggest problem was dealing with the inevitable snapped bolts (I had one on the tubo to manifold joint and one on the turbo itself). Many do this job in situ by pumping Mr Muscle down the pipe from EGR to turbo but I didn't fancy that. I have to say that a Mr Muscle soak nicely shifted all the cacked on gunk once the vane side of the turbo was off.

Keith

 

[Shawnobi]

Another vote for sticky Turbo vanes. Ideally a turbo rebuild. But if you can get away with Mr Muscle or what ever then give it a go. But I've heard mixed reports reading around.

 

[t3yls]

Get the mr muscle out!
Look on youtube for turbo clean with mr muscle if you've not heard of it before


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[halftone]

If the car stood for 14m I would suspect surface rust inside the turbo, impeding free vane movement. Easy to fix with abrasive paper but needs the turbo removed and dismantled. I had exactly that on my 1.9 which stood for 4m after it ate a swirl flap, before I bought it to fix. Mr Muscle won't work with rust.

I suggest you test movement of the actuator lever using a vacuum pump. A cheap Chinese copy of a Mityvac will be about £15 on eBay and should establish whether actuation is smooth and proportional to vacuum. The lever should move forward to the limit stop by about 17 ins Hg on the gauge.