Inlet manifold sludge and EGR

Veg_Ian · Post by **Veg_Ian** » Sun Oct 08, 2006 10:05 am

The yellow "X" marks the spot

Fredanz · Post by **Fredanz** » Sun Oct 08, 2006 10:14 pm

Veg_Ian wrote: The yellow "X" marks the spot

Thanks for that. I thought it had to be that exposed tube, as I just couldn't find an alternative. Curious though, because that means it was disconnected (yet not blocked) before I even began...

Brighton Bongo · Post by **Brighton Bongo** » Mon Oct 09, 2006 9:01 pm

Anyone know what that little green plastic thingy is located just above the gearbox dipstick under the drivers seat? Its near the egr thingy.
Mines broken and I'm wondering if its important or one of those environment things we can do without. Its awfully tight on the 2 tubes and I not surprised its pulled apart. One pipe is covered with a heat proof sleeving.
Anyone know where I can get another from.
Cheers
Bonza

I was about to ask the exact same question, mine is snapped in half , and the feed from the air filter tube has also snapped off. Tiny bits of brittle plastic.
It goes to the same plastic thing that the egr tube terminates at.
Does anyone know what it is??
It also seems to have electrical connections, to the left of the 'X'

flashgordon69 · Post by **flashgordon69** » Mon Oct 09, 2006 9:04 pm

Have done the EGR mod tonight and as i pulled the little black pipe off to put a bolt in it, it shattered into little bits, went and got some new pipe and all was well
took out for a test drive and hey presto no more smoke

after checking all the other little black pipes under the drivers seat side, have decided to change them, there all a bit brital, may be worth checking if you havent already

Bonza · Post by **Bonza** » Tue Oct 10, 2006 9:30 am

Thanks for the write ups on EGR, great help.
Posted that my vacuum non return valve (green thingy!) is broken in two.It appears to have happened to others.

It seems that its part of the EGR system and provides suction to trigger EGR open at low rpm. As I see it if blanked off the green NRV thing the EGR control solenoid could not receive any input of vacuum and thus not function at all.
This would save me the cost of a replacement NRV plus disabling the EDR at the same time. Am I correct in my thinking?

What does the electrical input to the EGR solenoid do? Maybe its a speed signal to activate at idle only? Dont know.

Veg_Ian · Post by **Veg_Ian** » Tue Oct 10, 2006 11:29 am

Yes something like that. I would need to check further but there's another pipe on the solenoid inferring it provides vacuum for something else. I'll need to trace it tonight when I get home. If the second pipe is not for the EGR then you may still need the green NRV for the other device. If all part of the EGR then yes, don't bother replacing it.

Bonza · Post by **Bonza** » Wed Oct 11, 2006 2:14 pm

Just done 30 miles without the green NRV and I tell you what it feels like it has a bit more zip. No other probs or overheating etc. I did try to will the fuel gauge to slow up a bit but as I cruise at 80 theres no chance!
Interesting, the NRV allows air into the solenoid at the top. Should it be the other way round if its a vacuum? I reckon it allows an increasing air pressure from the intake system to trigger the solenoid not a vacuum.
Bonz

Veg_Ian · Post by **Veg_Ian** » Wed Oct 11, 2006 2:37 pm

Well I'm not sure. I had a look at the whole gubbins and couldn't get my head around it. It looks rather over complicated for what it is trying to achieve. It looks like it could be activating a vacuum at low revs so as to pull in gases from the exhaust ie. EGR working with diaphragm open. The alternative vacuum pipes look as though they pull filtered air from the filter to inlet manifold pipe for when the diaphragm is closed at high revs and do what? Pass it back to the inlet manifold? Now that doesn't make any sense so I'm assuming I've got it wrong.

You may have a point about the vacuum though Bonza. The Townace gets its vacuum from a vacuum pump on the back of the alternator and is generated by the turning of the alternator pulley. Vacuum is also used to operate other components such as the tacho gauge.

As no such pump appears to be present on the Bongo, you may well be correct in deducing the diaphragm is triggered by air pressure not vacuum in the way you describe. It would certainly explain the elaborate excess of pipes and the nrv.

It does make one wonder though whether you could simply remove the whole lot - diaphragm, solenoid, electrics, nrv and pipes and simply block off each manifold entry and plug the outlet on the previously mentioned filtered air pipe.

Maybe when I have a free Saturday afternoon I'll have a try and see what happens .....

changabang · Post by **changabang** » Sun Oct 22, 2006 7:41 pm

Very interesting thread. Just read the last sentence of the Wikipedia blurb which states:-

'In all cases, the EGR system will need to be operating normally in order to pass emissions tests.'

Does this mean if one disables the ERG system there is a chance the engine will not pass emissions tests as it would not be operating normally or have I missed something here?

dreamwarrioruk · Post by **dreamwarrioruk** » Sun Oct 22, 2006 7:53 pm

completely blanked ours off from the inlet manifold near to the front of the engine. passed mot with no problems

Veg_Ian · Post by **Veg_Ian** » Wed Oct 25, 2006 8:51 am

I've not read the source of your quote but would guess it refers to a petrol engine. The emissions in question for a diesel are not tested for in the UK thus making the EGR unnecessary.

koxxwasp · Post by **koxxwasp** » Sun Oct 29, 2006 6:07 pm

Just done the old EGR thingy. i don't know but it seems to go like STINK now.

Happy days

Allans · Post by **Allans** » Thu Dec 14, 2006 9:46 am

i don't know but it seems to go like STINK now.

If it was losing pressure, you will have improved this. It can also leak exhaust gas.

I've done a similar modification several times for customers vehicles, but I use two laser cut Blanking Plates.
The EGR remains in place but is out of use completely, the same as if it was removed.

I've done this mod to Pajeros also. There's some controversy about blanking the EGR - some people prefer to clean things, others won't blank or clean. This way, if anyone ever wants to re-instate the EGR, all they have to do is remove the Blanking Plates.

mikeonb4c · Post by **mikeonb4c** » Thu Dec 14, 2006 1:27 pm

Here's a question. I have a 1995 Bongo with 67k miles on the clock and and I assume it has EGR. So I disable it (but in such a way that I can connect it before its MOT so it can pass its emissions test). All fine so far.

BUT I already have a load of sludge in the pipes. Will the existing sludge slowly disappear with continued engine running now the EGR is no longer piling it on? Or will it 'dry' out, harden and become difficult to remove. Or it makes no real difference because it is not doing any harm? Or it is possibly reducing performance by resticting flow in the affected pipes? Finally, how difficult is it for a non techie like me to atempt to clean the pipes?

As previously observed, this is a fascinating thread.

Mike

Veg_Ian · Post by **Veg_Ian** » Thu Dec 14, 2006 1:36 pm

Just to reiterate, the MOT does not test for the gases that are reduced by the EGR. The MOT test is more interested in smoke particulates not nitogen oxides. So the smoke test will be the same whether you disable the EGR or not.

Do you have sludge in the pipes or is that supposition? Crud usually builds up in the inlet manifold and then creeps up into the turbo pipe where it meets the inlet manifold. I think you will find that it is already pretty hard.

Disabling the EGR will prevent any further build up of crud but for a completely clean system you will need to disassemble the manifold and pipes and scrape it out. It won't go away on its own.