Technical 2004 2.0 JTD EGR

[Lotus26R]

Has anyone experience of removing/cleaning the EGR on a 2.0 JTD please?

If so, which bit is it that gets gummed up, and what happens when it does?

On our Smart, the soot/tar build up in the valve reduced the effective size of the intake so radically reduced the engine power. Cleaning the gunge out restored normal performance instantly.

On our Ducato, the valve seems to operate normally. I assume that the exhaust gas then travels down the pipe, through the cooler and into the intake manifold to be sucked into the engine. Even if the valve/pipe/cooler gunged up completely, I'm not sure how that would harm performance - wouldn't the engine then just breathe clean air and be better for it? I guess EGR blanking plates do just that. Does the gunge accumulate further downstream (ie, in the manifold)? if so, how would we clean that out?

Has anyone had success with diesel fuel system cleaners or are they generally considered to be snake oil?

 

[LandyAndy]

The gunge then to accumulate in the inlet manifold where the sooty air meets the colder, and often oily air that has come the inlet, passing the crank case breather, before entering the intake manifold.

This is the intake manifold on my X250 Ducato with 32thou miles on. That I have now EGR blanked. I know it’s a different engine so there will be some difference.

 

[Lotus26R]

Thanks LandyAndy - that does make sense although the implications of a blocked up inlet manifold are more tricky to resolve - inlet manifold off at least. I wonder if that's possible with the engine in situ? It may make it more responsive to cleaner additives though.

 

[LandyAndy]

I cleaned mine as much as I could with manifold fitted and swapped MAP sensor for a new item after. I removed the throttle body part which gave me access and the image shown above. I’ve then blocked off my EGR. put some chemicals in the fuel and I also have got some spray cleaner to run through the system which is apparently very good, and a way of cleaning the air side which fuel additives won’t/can’t touch.

Wynns Direct Injection Valve Cleaner - 500ml - Restore Correct Airflow - 28879A 500ml

The UK's largest independent supplier of automotive oils, fluid and parts. We've products to suit any vehicle, from full blown Race / Track weapons, to Daily Drivers looking to save money. Plus FREE expert advice & recommendations - OPIE KNOW OILS

www.opieoils.co.uk

You spray into the throttle body as the engine runs, cleaning out the pre cylinder area.

 

[Lotus26R]

Interesting. I'll take a photo later but when I removed the throttle valve yesterday, the intake was clean for as far as I could see - I might run a bore camera round the corner later and see if that reveals anything unpleasant.

 

[LandyAndy]

The question you ask above in first post is a thought I had, that if the EGR system get gummed up then the engine just takes the clean air. Great. Brilliant. But what I then went onto learn was about throttle bodies, and that they are there to shut off the air in, whist the EGR is open to force induction from the exhaust. So if the EGR is gummed up, so restricted gases, the system is now suffering restricted dirty exhaust air, but also fresh air as the TB has been closed/reduced. The other thing I learned, EGR also get stuck open. Again all this is on X250, but standard practice I believe.

 

[Lotus26R]

Sounds like I'll have a busy day then - thanks for the thoughts - I'll let you know how I get on later. Cheers. (also would explain why the TV solenoid had been disconnected)

 

[LandyAndy]

Indeed. If you want I can give phone number if will help you at all.

Good luck. Hope you enjoy learning.

 

[Lotus26R]

Appreciated - stuck (largely/partially) open would tie in with the fact that my measured air flow is several times smaller than the calculated/target flow.

I found this a very useful diagram - this ties up too.

https://www.ms-motorservice.com/en/technipedia/post/air-mass-too-high-or-too-low/

 

[Lotus26R]

OK, EGR opens and closes properly. Runs like a pig when all connected - much better when EGR vacuum pipe pulled off.

Target airflow and measured airflow factors apart unless EGR and Throttle Valve disconnected. Both readings very close like that but runs dreadfully as well. New air filter made no difference.

Back to the drawing board.

 

[Lotus26R]

The question you ask above in first post is a thought I had, that if the EGR system get gummed up then the engine just takes the clean air. Great. Brilliant. But what I then went onto learn was about throttle bodies, and that they are there to shut off the air in, whist the EGR is open to force induction from the exhaust. So if the EGR is gummed up, so restricted gases, the system is now suffering restricted dirty exhaust air, but also fresh air as the TB has been closed/reduced. The other thing I learned, EGR also get stuck open. Again all this is on X250, but standard practice I believe.

This makes plenty of sense - the EGR is open at idle (I can see and measure), the Throttle Valve is closed at idle (I can see but can't measure). Did you learn if the two should always mirror each other - ie EGR open, TV closed - EGR closed, TV open or if they follow different strategies.

Your photo looks like the the gunge in the inlet manifold was really quite hard - do you think the Wynns would have had any joy moving it? I really can't access my manifold without taking it off and I'd worry about displaced hard bits getting sucked into the engine and into the cat (which may also be a problem thinking about it)

When you fitted the blanking plate you mention disconnecting electrically - did you just pull the plug and live with the red light? Did you notice a big improvement once all done?

Thanks

 

[LandyAndy]

This makes plenty of sense - the EGR is open at idle (I can see and measure), the Throttle Valve is closed at idle (I can see but can't measure). Did you learn if the two should always mirror each other - ie EGR open, TV closed - EGR closed, TV open or if they follow different strategies.

Your photo looks like the the gunge in the inlet manifold was really quite hard - do you think the Wynns would have had any joy moving it? I really can't access my manifold without taking it off and I'd worry about displaced hard bits getting sucked into the engine and into the cat (which may also be a problem thinking about it)

When you fitted the blanking plate you mention disconnecting electrically - did you just pull the plug and live with the red light? Did you notice a big improvement once all done?

Thanks

The EGR and TB do mirror each other as you say. This is to make the inlet suck the exhaust gasses through. At tick over your EGR should be closed, and as so the TB fully open. If you then rev your engine high, and come off the acc pedal, your EGR then opens, and the TB closes. This then remains for 1 minute before the EGR, and TB swap back. The gunk in my inlet does look hard, but in actual fact is soft, and almost dissolves into oily slime. This is due to it mixing with the oily air from the crank breather. The same gunk also covers the MAP sensor causing incorrect readings.

Initially I unplugged my vac solenoid and this stop the EGR system working, which made mine drive better, as it stopped the TB closing, but my ERG is stuck open, so still had some issues, and now a light on dash. I then fitted a blanking plate that I made between the EGR cooler and exhaust manifold. This then made everything great, but if I reconnected the vac solenoid it then makes new problems as the TB now closes, which practically shuts off the air supply to the engine at times. I’ve now had it removed by modifying the ECU, and so far everything is great. Lower engine temps, no black smoke, no white/grey smoke after start up, more power, no annoying buzz under the bonnet.

I went for the ECU alterations as it won’t pass the MOT with light on, and also I wouldn’t know if another issue happened as light was already illuminated.

 

[Lotus26R]

Thanks - my setup has two vac solenoids - 1 for EGR, 1 for TV. At idle, my EGR is open and the TV is pretty much closed. If I put the palm of my hand over the engine side of the TV it immediately opens, closing again when I take my hand off.

My inlet manifold seems pretty clean where the cooled exhaust gas enters. I improvised by sticking a bottle brush up it to check. It came back sooty but not the slimy wet gunge that I'd feared. It didn't seem restricted.

It may be that my vehicle is performing as it should and that 27mpg is the best I can expect.

I'm going to live with it for a while but thanks to all for feedback.