Bit of fun with MK7 EGR Valve

[rossco_pb]

]In the process of replacing my MK7 140ps RWD EGR valve and decided to have some fun with the old one first.

I bench tested the the motor drive by applying 12v to pins 1 and 5 of the connector. It seemed very noisy with gear grind and sluggish and of course sooty and dirty. Took it apart and cleaned it out and lubricated all the shafts and gears and reassembled and sounded and responded much better. Really interesting spring return mechanism...

It was then that I decided I would try an experiment that I had considered in the past to see whether or not introducing air instead of exhaust into the intake manifold would work, ie not result in an EML situation.

To achieve this I bored a hole into the exhaust flange area and glued a piece of pipe in and checked it was airtight and that movement of the valve itself was not compromised.

I now need to install it and obviously I will blank off the flange from the exhaust proper. Once I achieve that I will let you know the results.

Bit of fun if nothing else eh Some pictures below...

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[loot]

Was this egr faulty? Was it bringing on the eml? Was the fault code p0404 range/performance?.

The strategy you want will require a working egr. And also you'll require a relay from the motor as a controller for the introduction of air so that it can mimic the egr function, or have the air situated so that it can't pass unless the egr opens.

Then possibly you'll need the correct air pressure or even to mimic exhaust pressures.

If not you'll get turbo high/low faults, and on a vnt you may even get running problems similar to scv fluctuating as it can't regulate itself.

Or you may get no problems.



Have you done it yet and does it work?


Ps. P0404 range/performance will be the potentiometer fail in the egr head, when you open the valve you'll see it raise, that pin goes in the head and pushes on a potentiometer switch.

Bloody Brussels

[rossco_pb]

Ps. P0404 range/performance will be the potentiometer fail in the egr head, when you open the valve you'll see it raise, that pin goes in the head and pushes on a potentiometer switch.

All good points, especially about the potentiometer. Do you know it resistance range as when I compare to the new one there is a huge difference....

Might have to go to plan B and make up a 12mm flange with fresh air supplied into the side of it and fit with the new EGR.

Cheers

[loot]

There won't be any difference in resistance dance but a faulty 1 will have incoherency ie 0. Like a stereo volume knob that crackles

[rossco_pb]

There won't be any difference in resistance dance but a faulty 1 will have incoherency ie 0. Like a stereo volume knob that crackles

Big difference in the ones I have - old one about 4k max across the resistor and varies down to about 2.4k whereas new one is only in the hundreds of ohms, like 220ohm max. Very odd...

[loot]

Doesn't make sense
Maybe the wear on the resistance material causes it then?

If you cut the head bit open you'll see a 3 pronged piece of metal that slides up and down the ceramic piece. It's a linear potentiometer, I assumed that eventually it would not give continuity in places but going out of range could be possible I guess.
Same result though

[rossco_pb]

Ok more fun. Reinstalled the modified EGR valve with some very flash plumbing to a tube that I had put a hunk of foam in as a basic air filter. Took it for about a 10km run and no EML or obvious issues other than the foam filter blowing out presumably due to boost going out the EGR at throttle change. Can't do proper test as waiting on a replacement intercooler to intake hose from the UK due to it splitting. Taped it up but that failed after a while. Would have gotten one from Ford NZ but they only had the gold plated version Couple of pics below:

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[rossco_pb]

Out of interest just wondering if anyone has messed around trying to replace the EGR electrical responses with a basic electronic circuit so that EGR can be bypassed totally (I know about deleting from pcm, that a different method)

Not quite sure how the 12v motor controls the valve position (if at all,ie could be just open or closed) as the motor is a standard brush motor (not stepper) so when power applied it just runs and valve opens and then when power removed the return spring assy closes the valve. Seems pretty basic but perhaps the motor is pulsed to more or less maintain the valve position with pcm using feedback from pot and juggling the motor on and off...

[rossco_pb]

The replacement intercooler to intake hose arrived and fitted. Road tested the beast with the MK1 EGR mod and after about 20km up hill and down dale no ELM and power and boost appears normal

Going to sort out the Mk2 version now which will be a 12mm flange with a pipe fitting into which fresh air will be able to come and go via a small air filter - the type used on rocker covers and the like. When my EGR finally dies I will put on the new one with this flange installed along with the blanking plate. Fun eh

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[rossco_pb]

And here be the flange with 12mm pipe that will have hose to small rocker cover type filter.

Flash eh well maybe not that flash- I'm not that great at brazing...

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[rossco_pb]

Couple pictures of the Mk1 version but with 12mm ID silicone hose and small crankcase filter sitting on intake manifold. Extra fitting in picture by filter is where I tapped my boost gauge in.

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[rossco_pb]

Well its been a while but my original EGR valve finally spat the dummy with it behaving erratically which in turn was affecting boost so out with the old and in with the new.

As part of the install I fitted my MKII version of my air feed idea which is basically a flange between the exhaust feed into the EGR and on that flange is a pipe that is then plumbed to a small air cleaner so the engine can send air in and out - just like it would have to the exhaust but of course in my case the exhaust port is blocked off.

It seems ok, no EML as yet but early days so will see how it goes....

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EGR position with flange installed - note how close it is to the coolant pipe - I had to move the screw part of the hose clamp to the top so it did not obstruct moving the EGR forward to make room for the flange

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Top view of the EGR and flange in place

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Fuzzy picture of the bottom of the EGR showing the short copper pipe that is brazed onto flange

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EGR from bottom with pipe that goes to small air cleaner attached

Anyways, the fun continues - the weirdest thing is that with the little air cleaner in place I can hear air going too and fro and quite often this is while there is quite a bit of boost showing on boost gauge - I can only assume this is an attempt to purge some of the soot that must build up back into the exhaust system (in a traditional installation)

[Mashee]

VERY good, my kind of mod.

Great to see someone brazing too. I went into Boral Gas the other day asking for some brazing rod and three dudes had no clue what brazing was...

Would love to experiment with how that operates with the "turbo" bypassing the lol-tastic intercooler and going directly into your egr pipe

[rossco_pb]

Hope my braze holds - best I could do with what I had on hand

Not sure about the turbo thing as intake is already at boost pressure - the introduced "additional" fresh air is an attempt to fool engine management into thinking the EGR is working, ie it should affect MAF readings

[Mashee]

Yeah...that turbo intercooler combo... If it was a supercharger then sure, have an intercooler...but a 5v USB desk-fan turbo?? I'm pretty sure the intercooler decreases airflow more than that turbo can actually generate!! Hence my silly bypass into the EGR suggestion. I really need to get onto forscan and check the MAF readings with just raw inlet suction vs turbo working vs no intercooler. I'm sure someone out there has done it already. I'll eat my shirt if this turbo actually increases airflow by more than a couple percent through that intercooler!