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Cleaning EGR passage ways
Posted 12 August 2010 - 09:24 PM
After chatting with a mate at work about his Ford Galaxy EGR & dealer problems I decided to have a peek at the Honda's set up.
I looked around on t'internet but didn't find anything that directly related to the Accord 2.2 i-ctdi, so I set about the car with the socket set!
Under the plastic cover and at the front of the engine there is the intake manifold and attached to that on the right hand side (looking at the engine from infront of the car) there is a butterfly valve block and the connection from the Charge Air Cooler (CAC). Attached to the front of the manifold there is a st/st link pipe that connects the EGR cooler to the intake manifold, the EGR cooler is under the manifold and the EGR valve is attached to the right of the engine block, I didn't look at that 'cos it looked too much like hard work.
EGR is a method of introducing an inert volume of gas into the combustion chamber to reduce the combustion temperature to less than 2500 deg C. This is the critical temperature where NOx is created.
Now, does the ECU know that the passage way is restricted and not letting the right volume of gas in?
And is the restriction messing up the clean running of the engine, perhaps making it less efficient or more smoky?
The gas route is known as the long route and is taken from the low pressure side of the turbo controlled with a valve, cooled and fed into the intake. In the case of the Honda the link pipe connects to a plenum in the manifold and is then fed through an open passage to mix with the air from the CAC then to go into the manifold again.
To be continued...
Posted 12 August 2010 - 09:41 PM
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I was on the phone today for about 15 minutes with Andy from powerenhancer who basically said the passages are so small within the EGR system that it could easily get clogged up throwing up insufficient flow on the EGR. Symptoms are also supposed to include blacksmoke. The fuel treatments allow the blocked up passages of carbon to be burnt off at a lwoer temperature, thus clearing the blockage. I would suspect simply changing an EGR valve for a new one may not resolve this issue completely as the carbon is still built inside the passageways as what has happened to a few people on here already.
I've done a bit of reading up on the diesel treatment from this company and its quite good. I think there have been one or two other members who have used it too. I will be putting the diesel treatment into the 7th gen over the next few days and report back with any improvements. I think I will remove the valve and scrape off as much carbon as I can, then add the cleaner to the tank of fuel.
Posted 12 August 2010 - 11:54 PM
I've not tried that fuel treatment but I have continuously been using V Power Diesel for almost 2 years and over 40k miles now - and I don't really experience any heavy smoking on full throttle (and it regularly gets full throttle). I've never taken my EGR off to inspect it but I do firmly believe that the great reliability I've seen on my engine has been two main things:
Good clean fuel and Good Oil.
There is no secret and it's not rocket science. Use the best fuel, and the cleaning agents inside the fuel will eventually help keep everything they touch and pass through.. clean.
I might try some of that fuel cleaner at some point, but to be honest I'm a firm believer in proactive maintenance. No point waiting for the problem to happen and then retrospectively try to fix it.
Posted 13 August 2010 - 08:28 AM
Posted 13 August 2010 - 08:31 AM
Posted 13 August 2010 - 09:07 AM
Posted 13 August 2010 - 11:42 AM
Posted 13 August 2010 - 11:55 AM
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One thing is clear BG have a strong marketing machine. What I gather from this thread is that for the diesel application at least, it's not a bad product but it won't work miracles. Something called Seafoam seems to be the flavour of the month.
If anyone buys and tries this stuff in their diesel, please do report back. For the time being, I'm of the view.. if it ain't broke... leave it be ;)
Posted 13 August 2010 - 12:01 PM
The EGR passageways after the EGR cooler are about 35mm dia, not so small as to clog up easily I would have thought.
I'll just add here that nothing has broken or become faulty, I just got curious.
Continued from above:
What I found:
I removed the link pipe first, this is the easiest bit to get to, and in it there was no significant build up just a thin layer of soot. However in the manifold there is a plenum feature, that I mentioned before, this was guinked up. I can not say if it was completley blocked as I started digging out the gunk with a lolly stick.
What I realised was I should have taken of the CAC feed and the valve block first to see the extent of the gunking. If you are going to try this it's best to remove the cover stand-off and little bracket that is attached to the valve block and then take the block completley out. It was the same story in the valve block, heavily gunked and when I dug into the dusty surface the deposit was a viscus sticky black tar.
The whole de-gunking operation liberated about 1/2 a mug full of gunk, mostly from the plenum.
I think that the exhaust gas is still warm when it gets to the manifold and the manifold is cooled by the air from the CAC, this then cools the Exhaust gas quickly depositing its gunk. There was a generous coating of tar on the CAC link elbow and I am wondering if much gunk makes its way in to the CAC reducing its efficiency.
When I started the car after I put everything back together the MIL lamp lit up and gave the error P2017, I had forgotten to plug in one of the sensors. There does not seem to be a significant change in the cars performance but I am convinced the engine is making a slightly differant 'tone' and I think that it might be less smoky under full load.
Results from the fuel efficiancy test will follow, the car is being run mostly through town at an average speed of 15mph (that windes me up!) with lots and lots of traffic lights.
Posted 13 August 2010 - 02:10 PM
Posted 14 August 2010 - 03:54 PM
Posted 14 August 2010 - 06:28 PM
Posted 15 August 2010 - 08:09 PM
Just a thought, perhaps some loose bits were left in the air intake once you cleaned it and were sucked in? That would explain the sound you talking about. I dont think carb cleaner would be able to break the engine.
Is it possible to dismantle the intake manifold to clean it properly?
Posted 17 August 2010 - 08:14 AM
I was going to have the EGR off for an examination and clean, but I know it will be filthy, the question is; is it sticking open a little? Having read up about BG244 mention in this thread, (though I'm not a fan of 'additives' or 'miracle' cleaners generally), I'm going to give that a go first. For the price of a less than half a tank of fuel it seems like it's worth a go. My car had done 82,000 miles when I got it, having no idea what fuel it has had for all those miles a good clean won't go amiss anyway.
I'll report back after the BG244 has been run through.