de-coking egr

What car?

C3

on 19/03/2010, Fred supposed :

Carb cleaner will be the quickest and most effective. You will also see the results almost instantly.

I'm not sure how effective the injector cleaner might be, but ATF is pretty much the same stuff except the cleaner has added ingredients (paraffin?). That is intended to be put in the fuel tank.

Thanks. I have been wondering about this. Why is carb cleaner good for removing soot from an egr pipe? After all, the fuel mixing in a carburettor is unburnt so there should be no need to remove carbon should there?

Fred submitted this idea :

It removes the shellac from the fuel and the carbon deposits - you sometimes get back-fires into the carb.

Don't think the OP mentioned the vehicle make and model, but I'm pretty sure it's not a Model T Ford...

Chris

Hi, I didn't mention it in the very first post but I thought I did say later on that it's a Citroen C3. I've just looked in the Haynes book and that says the egr valve is buried at the back of the engine. Great;(

I've seen some vacuum gauges on ebay so I'll get one of those to connect to the egr valve and see what it says. Is there anywhere else I should measure the vacuum?

Where do I need to spray the carb cleaner? Just in the egr pipe?

Thanks again.

Chris Whelan pretended :

I don't think Model T's had an EGR.

Indeed. I also doubt that a vehicle with an egr has a carb...

Chris

However, carb cleaner is good for cleaning EGR's :-)

Why? genuine question.

Rob gurgled happily, sounding much like they were saying:

Simply because fuel injection is an easier way to emissions benefits, and started to become damn near ubiquitous before EGR started to be particularly common.

It's not impossible - my Saab has EGR, whilst 'erselfs 205 is the same age and has a carb - but I just can't quite see it.

in this case (the C3) it is very unlikely as it seems it is a diesel.

That's why I asked as it may be confusing as to what is being referred to as EGR.

EGR was some of the first bit of pollution gear fitted and it was to recycle the exhaust gas so more exhaust fuel had a second burn to reduce the emissions.

When injection engines came along the fuel being metered better reduced the pollution with a more even and complete burn.

Turbo engines operate differently again.

There was a lot of unburned fuel down the exhaust when fuel was cheap. Pre mid 70's era.

Its been the development quite a few years now to comply with pollution regulations.

Could be wrong!

Yup, it's to reduce the formation of NOx by reducing peak combustion temperature, there's very little unburnt fuel in your exhaust.

Rob gurgled happily, sounding much like they were saying:

Umm, the engine I have with EGR is an injected turbo.

EGR valves are notoriously troublesome on several recent common-rail turbo diesel engines.