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Discussion Starter #1
This isn't an engine problem, more a request for some help understanding EGR valves.

I've got a 2005 1.9 mJTD 16v and last year had issues with it being low on power at low revs.

I read a few of the posts on EGR valves and ended up removing and cleaning the valve and manifold inlet of a fair amount of crud, which seemed to sort the issue out.

What I don't understand is how a lot of posts suggest installing a blanking plate (or at least a flow restriction plate) over the EGR manifold to do away with having to remove and clean the valve from time to time. But if the problem causing low power is a blocked EGR valve, surely a blanking plate is equivalent to a completely blocked EGR valve? How can a blanking plate resolve the low power issues associated with a blocked EGR?

Just trying to understand the engine better :)
 

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If the valve is stuck closed, I think it'll throw the engine into limp-home mode.. When the ECU tells the valve to move but the valve doesn't, the ECU sees this is a big problem so defaults into limp-mode...

I believe the EGR valve can stick open as well as closed, which would cause rough running and engine fault codes...

Also the knock on effect of intake manifold crud to consider - swirl flaps! In the later 16v engines (CF4) with the plastic manifold body, the metal swirl flaps can get stuffed up and break off.. If/when this happens, you can be faced with a huge repair bill as the engine chews up the metal flap and/or spits out the shrapnel into the turbo....
 

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Discussion Starter #3
Thanks for the info, that explains it a little more. I've never had any engine warning lights which I assume you'd get if the ECU went into limp mode. I've had a bit of sluggishness again recently which seems like it can't just be the EGR valve again only 6 months since I cleaned it out, so if it comes back from the 84k service next week and still doesn't feel quite right I might be back on here for some more pointers.
 

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get it blocked off and deleted from the ECU that will prevent your engine light coming on .It stops all the black crud from blocking your inlet manifold .I did mine thousands of miles ago after having to change the inlet because the swirl flaps were sticking. In my opinion its the best thing you can do for yourself and the car
 

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Yeh, part of the problem is the EGR gets slower and slower to react, looking at the mechanism ( when you take the solenoid off) is that it can only really fail open as the soot collects in there, then the main problem is the solenoid ( the pin) in the EGR corodes with the acidic gases etc produced in the exhaust, and gradually gets worse and worse.
Make sure you clean your map sensor too, this is an easy way to see how cruded up your manifold is. You get soot from the EGR and oil from the crankcase breather ( that going in through the turbo).
The good news is with a bit of time, the oil and pressure can help to clean the manifold, esp with a bit of cleaner sprayed through the available ports ( I suggest EGR cleaner as it's designed to be ingested by the engine). The engine just gets smoother with time.


Any spelling/ grammatical errors are purely there to annoy!
 

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Guys, being a new 159 owner, who doesn't like the crazy things manufacturers put in our cars, can you please provide us with a link to a write-up on how to block the EGR?

Another related question is this. For my BMW X5, I have a suite of programs and a special USB-ODBC cable, with which I can change various parameters of the car. I got all these from ebay. Is there a corresponding cable and software for the Alfa? I see mentioned "delete the EGR from the ECU" but how can I do it? Paying the stealership the money they want for connecting my car to their computers is out of the question, unless it is absolutely necessary.
 
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