Inlet manifold sludge and EGR

Technical questions and answers about the Mazda Bongo

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Veg_Ian

Post by Veg_Ian » Tue Sep 05, 2006 1:36 pm

Nice one Rob, that would be helpful. In the absence of the much awaited workshop manual would it be possible to take a picture of the EGR system with pipe going back around the engine and pipe entry points? If you've already stripped it all down, no bother.

Cheers
Ian
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Post by dandywarhol » Tue Sep 05, 2006 10:45 pm

I have been meaning to bypass the EGR for a while now but haven't got round to muddling about with the pipe/bearing ball route. I'll go down your route of disconnecting the vac pipe Ian.......cheers
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Post by dreamwarrioruk » Tue Sep 12, 2006 5:21 pm

just had ours into the garage. tons of smoke out of exhaust, expected turbo blown. After 4 hours in garage the said inlet manifold and egr valve have been inspected. Lots of grime and sludge inside. Garage put a metal gasket between the inlet manifold and the metal pipe from the egr valve. Instantly stopped the plumes of smoke. There is still a little blowing out but will take a while to clear. Fingers crossed.
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Post by dreamwarrioruk » Tue Sep 12, 2006 9:09 pm

nop it isnt, just been out, blowing smoke out, smells of coolant and have lost some so guess what
its the head or gasket.back to another garage
RobnKathryn

Post by RobnKathryn » Tue Sep 12, 2006 10:32 pm

I'm feeling for you dreamwarrior.....I'm in a similar position. I took my cylinder head off and gasket seemed ok, so it's now in a workshop being pressure tested for cracks. Chances are it's cracked because of white flakey bits in bore, so I'm told. Also my exhaust manifold is too warped and twisted to be skimmed so a replacement is necessary!

Hope yours isn't so bad............Rob
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Post by dreamwarrioruk » Tue Sep 12, 2006 11:09 pm

thanks ive got a finger crossed
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Post by dandywarhol » Wed Sep 13, 2006 6:14 pm

I just bypassed the EGR this afternoon by blanking off the vacuum hose and there is an appreciable difference in the exhaust smoke..... I was begining to wonder if my engine was getting a bit worn even though it doesn't use any oil............thanks for the blindingly simple tip Ian :D
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GINGER

ERG thingy bob

Post by GINGER » Fri Sep 15, 2006 8:06 pm

My mate has a MK1 L/R disco with the erg system on it and he says that it is part of the servicing that you remove the inlet manifold and pipes for the intercooler and clean them out with a suitable cleaner and refit using new gasket.It helps to stop some of the black smoke problems apparantly? A big job methinks! :roll:
Veg_Ian

Post by Veg_Ian » Sat Sep 16, 2006 2:26 pm

Is your mate's disco petrol or diesel? If petrol then that's different and you need to keep it. Too much or too little EGR in a petrol engine may cause detonation (pinking). Diesel engines run by "pinking", and are designed so that EGR is only applied when cylinder pressures are low- eg light loads, idle. Engines are designed without EGR, then it is added to control emissions. Removing it cannot damage the engine.

If you've got black smoke look elsewhere. EGR filters out Nitrogen Oxides - these aren't black. Black smoke is caused by unburned fuel.
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Post by SimonT » Fri Sep 29, 2006 10:07 pm

Great thread. I am about to do an oil change for the first time since I bought my bongo - about 3k miles ago, so I will take a look myself at the sludge situation and will probably end up removing the egr hose

This site is flippin excellent :!:
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Chin

Post by Chin » Sun Oct 01, 2006 2:42 pm

Just a thought, is disable the solenoid having the same purpose as blanking the vacuum tube? As after reading this thread and looking into my own Bongo, I was surprise to find that my solenoid controling the EGR is actually faulty, but I had no complain of the engine performance so far.
Veg_Ian

Post by Veg_Ian » Sun Oct 01, 2006 8:24 pm

No you wouldn't know unless the solenoid had stuck at open rather than closed, EGR doesn't have a detrimental effect on performance. It should be marginally improved.
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Post by Fredanz » Fri Oct 06, 2006 12:51 am

Excellent thread, thanks Veg_Ian.

How important is the "10 years old" thing? My Bongo is 1998; does anyone know whether that means my EGR is better in some way and so won't be sludging up?

I lack the the time and know-how to take things apart to find out, but I figure I could manage the pipe tweak ok if it's still worth doing :wink: .
Veg_Ian

Post by Veg_Ian » Fri Oct 06, 2006 11:07 am

The technology is still the same for the '98 Bongo as my '97. I'd go for it and block it off.
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Post by Fredanz » Sat Oct 07, 2006 2:56 am

Veg_Ian wrote:The technology is still the same for the '98 Bongo as my '97. I'd go for it and block it off.
Well, I did but... it was hard yakker pulling it off the EGR diaphragm's tube, had to use vice grips in the end. And, in the process, the other end came off whatever it was attached to. IF anything (see below).

So now I have a 6" length of pipe, and I cannot find what the other end is supposed to connect to. I've hunted around with a wee torch and mirror where the pipe had once disappeared behind the black thing (solenoid?) that is top and right-of-centre of your photo. But I can't find a "spare" tube saying "connect me here".

So:

a) What are the consequences of leaving the vacuum open this way, rather than properly blanking off the pipe?

b) Any idea where it is supposed to connect and how I get at it? One possible location is at the right side of the above-mentioned black thing, where I have two vertical black tubes, the left hand one with a pipe on it, and the right hand one free. I don't see a similar tube in your photo, but there's some tape in the way. Maybe it was connected to that right hand one at some point. BUT, if so, it was definitely before I got in there and started mucking with things, i.e. if it's supposed to be connected to that, it hasn't been for a long time.

Since I'm in the wrong time zone to get a quick answer, I've taken it for a few test drives since doing this -- nothing seemed out of the ordinary. But I hope as hell having an open-air feed into the (solenoid-activated) vacuum isn't likely to result in longer-term harm or failures.

Thanks!
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