GrumpyGel
Well-Known Member
Surely he is getting confused. In a diesel there is no throttling of air to the cylinders - it flows pretty easily through the air filter, although it does have a convoluted route through the turbo and intercooler, but even that presumably does not restrict its flow greatly. So opening the EGR is not going to get air into the cylinders much easier. Similarly, it does not matter what the mix of clean to dirty air is, the same amount of fuel will be injected. Obviously you need a turbo to squash air into a cylinder to allow more fuel to burn, but not less air for less fuel.
Or an I confused!
Or an I confused!
Arctic2
Well-Known Member
Total gunfk we all now that the EGR get clogged up and work against the performance of the car, stick some tissue up both your nostrils and go for a steady walk lets say 2 miles, you may breath or gasp a little more, on the way back run as fast as you can see what happens then for a mile, the last mile remove the tissue, would you want your EGR and manifold to look like this below let alone the MAP sensor.
Do you prefer your EGR like this.
1
Or like this.
2
Or maybe bypass it like this.
3
Remember if your EGR looks like the first photo then your manifold will look like this.
4
5
And your MAP sensor like this one on the left, when it should look like the right one.
6
So i will stay with cleaning mine out or add the original bypass EGR.
7
Do you prefer your EGR like this.
Or like this.
Or maybe bypass it like this.
Remember if your EGR looks like the first photo then your manifold will look like this.
And your MAP sensor like this one on the left, when it should look like the right one.
So i will stay with cleaning mine out or add the original bypass EGR.
htr
Well-Known Member
I thought it and interesting article and was equally interested in what other's thoughts were about it. It seems too pertain to petrol engines as it doesn't specify which fuel it is. That oily mess in the induction 'plumbing' is the residue from the PCV 'flow' moving into the combustion chamber to be burnt. It's a bit like the range hood filters getting clogged with that greasy goop that we're expelling to the outside atmosphere. Those oil laden vapours from the crankcase are surely the problem and where it all clogs together creating 'choke' points. I re-plumbed the PCV circuit and added in an oil catch can which helped.
I suppose my question is: in order to get the benefits of the EGR system and not suffer the clogging of the induction pipework, how can we reduce/re-roote those oil laden crank case vapours so as not to be a problem?
I suppose my question is: in order to get the benefits of the EGR system and not suffer the clogging of the induction pipework, how can we reduce/re-roote those oil laden crank case vapours so as not to be a problem?
GrumpyGel
Well-Known Member
Is it the crank case vapours that causes the build up or exhaust soot build up that's made sticky from combustion residue or possibly tiny oil levels escaping the turbo - or maybe a combination.
Is the crank breather output fed into the induction system on the exhaust side of the EGR? I'd have thought it was fed into the clean air or manifold. This being the case, the crank breather could not be responsible for clogging up the EGR and as the clogging appears to start in the induction flow from the EGR area, probably not responsible for that either.
Nodge68
Well-Known Member
The goop is burnt oil, which gets into the air path either from the CV circuit, or is ejected from the turbo.
This fine mist of oil gets burnt by the hot exhaust gasses which EGR valve admits to the air stream, resulting in the goopy residue.
GrumpyGel
Well-Known Member
So the crank vent outputs to the air input to the turbo. The oil within it then gets pushed/pulled through the hoses to the intercooler then through hoses back to the plenum/inlet manifold where the EGR output also joins it.
It is only at the plenum/inlet manifold where this goop builds up, it does not build up in the hoses or intercooler (although oil will). The conclusion therefore is presumably that it is output from the EGR that is building up. That is also born out by the fact that the EGR valve itself gets gooped up, the crank vent output would not be drawn into there.
Nodge68
Well-Known Member
Absolutely correct. The CV gasses enter the air stream, between the air filter and turbo compressor housing, so anything that gets into the CV pipe, gets boosted by the turbo, and forced through the entire intake path, eventually making its way to the engine.
The oil in the air stream, is often burnt when the EGR valve is open, resulting in black goop.
I also believe the oil in the air stream, is responsible for the TD4 2k misfire, but I never got round to proving that.
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