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Hi. I am 4mths back into having an Alfa Romeo again and am very glad to be back :happy:
Something I have noticed though, when accelerating, the turbo boost gauge rises rapidly to 1.4-1.6 bar, then drops down and then increases again in line with engine load. On some occasions, particularly under extra load/going uphill the effect is more pronounced followed by a slight chopping noise if I take my foot off. Very rarely, the car has gone into limp mode (overboost protection?) although turning off the engine then restarting has resolved the problem. (I do need to check for any fault codes still - wip).
Reading through multiple posts would suggest a couple of causes: 1. the variable vanes are sticking and/or 2. a faulty boost control valve/solenoid.
Is removing the turbo for cleaning relatively straightforward and, if so, does anyone have a guide? Otherwise, how would one check the boost control valve?
Thanks in advance for any suggestions/guidance.
 
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Power loss fixed

Hi. I am 4mths back into having an Alfa Romeo again and am very glad to be back :happy:
Something I have noticed though, when accelerating, the turbo boost gauge rises rapidly to 1.4-1.6 bar, then drops down and then increases again in line with engine load. On some occasions, particularly under extra load/going uphill the effect is more pronounced followed by a slight chopping noise if I take my foot off. Very rarely, the car has gone into limp mode (overboost protection?) although turning off the engine then restarting has resolved the problem. (I do need to check for any fault codes still - wip).
Reading through multiple posts would suggest a couple of causes: 1. the variable vanes are sticking and/or 2. a faulty boost control valve/solenoid.
Is removing the turbo for cleaning relatively straightforward and, if so, does anyone have a guide? Otherwise, how would one check the boost control valve?
Thanks in advance for any suggestions/guidance.
Hi, I recently had problems with my Ti 2.0 159, changed the MAF and MAP sensors (good price direct from Germany) and cleaned the turbo, with oven cleaner spray of all things! Car used to loose power on WOT and uphill at times. Problem was solved with the turbo clean mostly but ran better after the MAF and MAP change. To clean the turbo = Raise on stands, drop belly panel, disconnect front exhaust pipe to turbo (need to remove the aluminium shields also), then disconnect the lower end of the front pipe to allow you to move the exhaust pipe away from the turbo. The clamp at the turbo is a bit awkward but ir can be prised out of the way. Then spray in some oven cleaner (mr muscle) - use lots of rags, protect aluminium and other bits - I used lots of rags and wore gloves - also had a pipe attached to the can so that I could get the pipe into the exhaust side of the turbo. Let it stand for about an hour, Wiggle the wastegate valve (used a blade of screwdriver to press down repeatedly as it sprung up, just to ensure it was free. (even disconnected it to check it and it was loose and free to move - excellent. Then reconnected to lever to the wastegate rod (don't drop the circlip!). reconnected everything in reverse, started it up and went for a few miles drive. I've not had a problem since - Job done !:beer:
 

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Many thanks for the turbo cleaning guide. Will try and find an opportune weekend to attempt this- perhaps when the weather is more consistent. With regard to the wastegate rod, is this only accessible from underneath? Also, is that separate from the VNT solenoid/boost control valve?
 

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May also be EGR valve sticking, although they tend not to cause too many issues on the 2.0.

If it is sticking open it will cause boost loss and surges.
 

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clean the MAP sensor, back of the engine in the intake manifold. if that's clean and you still get this issue the VNT inside the turbo is likely sticking from soot/rust.
 
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picture

Many thanks for the turbo cleaning guide. Will try and find an opportune weekend to attempt this- perhaps when the weather is more consistent. With regard to the wastegate rod, is this only accessible from underneath? Also, is that separate from the VNT solenoid/boost control valve?
This is accessed from above the engine - just by looking down at the turbo (nice change!). See attached pic for more info. The rod connects wastegate to the VNT. When the car is running, you should be able to see the rod moving as the engine speed is increased.
 

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