EGR mystery ...

Technical questions and answers about the Mazda Bongo

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Ian
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Re: EGR mystery ...

Post by Ian » Thu Jan 09, 2020 12:02 pm

Dave, email me your pictures and I will put them up for you. It's quicker doing that rather than explaning how to link to externally hosted photos etc....

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JulesMartin
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Re: EGR mystery ...

Post by JulesMartin » Thu Jan 09, 2020 2:00 pm

this morning I replaced the gaskets on my EGR valve with solid metal ones :wink: :wink: I must say it runs much better and seemed to get better and better I guess it's clearing out all the crud that's accumulated. much more responsive at low revs and smoother idle. left wiring in place as to the vacuum pipe. Whilst I was there I had a look at the non-return valve we've been talking about and on mine it is in the pipe running from the nearest solenoid to the EGR down into the big black inlet tube running under the EGR valve. The pipe from the EGR does not have a valve in it and looked to be the original tubing.
Martin
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Re: EGR mystery ...

Post by Ian » Thu Jan 09, 2020 4:01 pm

Here's Mybongoiscalleddave's photos:

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Re: EGR mystery ...

Post by MyBongoiscalledDave » Thu Jan 09, 2020 4:19 pm

So, to recap;

If I have the vacuum pipe connected both ends to the EGR and solenoid, it runs really really bad.

If I have either end disconnected, it runs beautifully.

I've had the EGR off and cleaned it up, it seems like the diaphragm works okay. I pressed it up and put a finger over the vacuum pipe and the diaphragm stayed in place.
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g8dhe
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Re: EGR mystery ...

Post by g8dhe » Thu Jan 09, 2020 4:43 pm

Geoff
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Re: EGR mystery ...

Post by MyBongoiscalledDave » Thu Jan 09, 2020 4:51 pm

So I saw this last night. The pipe numbered 93-5104 (top-right of page) definitely isn't 170mm long, doesn't have a one way valve and goes somewhere under the engine block. I don't know where it's supposed to go. Does anyone know what component does 1312 13-341 refer to?
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Re: EGR mystery ...

Post by g8dhe » Thu Jan 09, 2020 5:30 pm

I think you mean 93-5104 pipe ? That appears on this page the 13-314 refers to the bracket;
http://www.lushprojects.com/bongopartsm ... mgno=.html
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Re: EGR mystery ...

Post by MyBongoiscalledDave » Thu Jan 09, 2020 8:43 pm

This is awesome. Thank you! And your arrowed picture will prove to be more than useful, I'll explain below.

The plot has thickened. I contacted the previous owner to find out exactly when it had gone wrong, because something just wasn't adding up. Turns out, when it went in for loads of welding work, they had to strip down quite a lot more than expected. I think they've put the vacuum system back together incorrectly. She even said that the 'mechanics' were scratching their heads trying to work out where all the vacuum pipes went.

So, I will sit down with the lushproject webpage schematics and try to work out the whole vacuum system and put it back together correctly. Is their a specific page that refers to the vacuum system in its entirety?

And does the vacuum system work in a linear fashion? As in, does air start at the vacuum pump and finish in the air intake pipe?

Many thanks for you replies.

This is a fantastic forum to be welcomed in to.
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g8dhe
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Re: EGR mystery ...

Post by g8dhe » Thu Jan 09, 2020 10:51 pm

Your homepage for the mech. diagrams is here http://www.lushprojects.com/bongopartsmk2/ choose the year, then drill down to engine type and around the engine for the vacuum system pages. You can also tackle it from the overall diagram pages rather than by system elements, using the righthand coloumn once you know the page numbering there are actually a few pages that are difficult to locate other than by page number!
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JulesMartin
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Re: EGR mystery ...

Post by JulesMartin » Fri Jan 10, 2020 1:32 am

I know this is a long shot but one of the what looks like a vacuum hose leading to the injection pump comes off of the spill return rail. it could be mistaken for a vacuum hose and just maybe with the vac hose connected to the EGR it is sucking diesel not air?? I'm concerned that in the pics you put up that there is a vac hose coming from a solenoid down to the injection pump. I'll take a look at my layout (same engine same year) and try and give you a pipe by pipe walkthrough. I'll see if I can mail Ian with some pics and ask him to put them up for me as well
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Re: EGR mystery ...

Post by MyBongoiscalledDave » Fri Jan 10, 2020 9:31 am

Jules, this might not have been such a long shot. I noticed yesterday that the pipe you question, from the forward left of the EGR solenoid, isn't of the same rigidity or circumference as the others. And it's connected to a metal line, which looked awfully to me like a fuel line. I'll also get a picture taken and passed over to Ian (again) to show.
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JulesMartin
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Re: EGR mystery ...

Post by JulesMartin » Fri Jan 10, 2020 11:43 am

I've written up a walkthrough and taken some pics and sent it all to Ian who I hope will be able to put them up here for you. in the interim the nearest solenoid to you which sits in front of the other three has a pipe leading to the big black air intake tube. This pipe has the one way valve in. The next pipe along the solenoid goes over to connect to the solenoid behind it and the third pipe goes off to connect to the EGR valve
Martin
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Re: EGR mystery ...

Post by Ian » Sat Jan 11, 2020 10:04 am

Here's the info from Martin starting with the walk through, followed by photos

https://igmaynard.co.uk/download/vacuum_pipes.pdf

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MyBongoiscalledDave
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Re: EGR mystery ...

Post by MyBongoiscalledDave » Sat Jan 11, 2020 6:14 pm

Thank you very much! This is so informative. From reading your PDF, it's clear now that there definitely are vac pipes in the wrong places.

I'm hoping to get on to this tomorrow, then get onto tackling the leak on the fuel pump!

Many thanks!
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JulesMartin
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Re: EGR mystery ...

Post by JulesMartin » Sun Jan 12, 2020 12:35 am

glad to be of help
Martin
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