EGR mystery ...

[MyBongoiscalledDave]

Hello Bongo Fury,

I'm a soon to be (tomorrow) fellow bongonaut! After many years, I eventually got around to owning my very own Bongo. I'm very excited about it, but mine has come with, from what I can tell, is a singular issue.

I'm driving a 1996 (N) 2.5l TD. I thought that EGR needed looking at from my hairy drive home after buying it. I've experienced similar symptoms in other diesel motors I've owned. So I took it off, cleaned it up (it wasn't in a terrible state) and put it back on. All being well, I thought it was running smoothly, like, really nice.

Then I realised that I hadn't plugged the electrical harness or the 6mm hose back in. So I plugged them in, and it ran horribly, like really horrible. Unplugged the 6mm hose, runs beautiful, plugged back in, like a dog.

So you see my problem. What does this 6mm hose do? And why should it run so terribly when it's plugged in? I could just order a reconditioned one from bongospares, but I'd like to find out whether it's the EGR valve, or the sensor that the 6mm hose is plugged in to.

Or it could be the wiring, but I don't this is very likely.

Does anyone have any wisdom?

Kindest regards, on this my first of, hopefully very many posts.

Adam

[g8dhe]

You might want to trace the vacuum tubing out and see what valve it is that is operating/not operating! http://www.lushprojects.com/bongopartsmk2/

[MyBongoiscalledDave]

Nice one, cheers Geoff.

Okay, I've had a look at your link but can't see the hose coming from the top of the valve. From memory, I could see that the 6mm comes from the top of the valve and is only about 6 inches long and goes to what seems like a sensor. Maybe it's the sensor rather than the valve?

[MyBongoiscalledDave]

I've checked the 6mm vacuum pipe. Not blocked, so it must be the sensor / solenoid thats faulty. I just don't know what this part is at all. The part has three 6mm pipes coming off of it. One is coming from the EGR valve. One (very short) 6mm pipe goes to another similar looking sensor behind it. These two are on top. Then coming from the left hand side is another 6mm pipe heading off around the front or the engine bay.

I tried to attach a picture to no avail. Error message saying that the attachment was too large (even though the file was only 376kb) I can email a copy to anyone who thinks they might be able to help ...

Any help greatly appreciated.

Cheers,

Adam

[nth]

The vaccum pipe is what opens & closes the valve. The electrical connection is a position sensor so the ECU knows what position the valve is in.
Best thing to do with the EGR valve is to blank it off with a metal plate, your engine will thank you for it.

[MyBongoiscalledDave]

I've heard such rumours. But would it still pass an MOT on emissions?

[MyBongoiscalledDave]

And herein lies the problem. I'm all up for blanking it off after the MOT but I can't do that until I diagnose the first issue to get it through an MOT in the first place.

It must be something to do with the valve/solenoid because that's where the vacuum hose goes to. With it unplugged it runs a dream. As it's plugged back in its choking.

I'm now struggling to know what part to find, seeing as I just don't know what it's called.

[JulesMartin]

I believe what your looking at is one of a group of 4 soloniods that have something to do with the cold start system. does the pipe have a one way valve in it? I think from memory that there should be a vacuum pipe from a solenoid to the EGR, another to the air intake just below the EGR. there are two other pipes that go from these soleniods down to the injection pump. there are other vacuum hoses going to the intercooler forward of the inlet manifold and a very short one behind the pump. any of these not connected will make it run rough. if i can find a picture of it all I'll try and put it up here

[MyBongoiscalledDave]

Thanks Jules,

The problem is that it only runs rough when the vacuum pipe from EGR to solenoid is plugged in. I'll have another play about with it when I get home this evening to see if I can further diagnose it.

Thank you all for all your advice.

Cheers!

[JulesMartin]

The vaccum pipe is what opens & closes the valve. The electrical connection is a position sensor so the ECU knows what position the valve is in.
Best thing to do with the EGR valve is to blank it off with a metal plate, your engine will thank you for it.

If it is blanked off with a plate what happens to the vacuum pipe and electrical connections? is it safe to just block the vac pipe and ignore the electrics?

[MyBongoiscalledDave]

For what it's worth, I think this is the part.

https://rover.ebay.com/rover/0/0/0?mpre ... 3810991883

[JulesMartin]

Yep I agree that is the part that the vac pipe goes to. Wow! good job it's not one of those that's broken, not at that price!

[MyBongoiscalledDave]

Yep I agree that is the part that the vac pipe goes to. Wow! good job it's not one of those that's broken, not at that price!

Ironically, I've come to the conclusion that this is definitely the part that is not working. Trying to source it cheaper! After another hour of diagnostic effort, this is the only part of get I can find that could possibly be the issue.

Also, re. Your question about one way valve, no, it's just a straight through pipe.

[JulesMartin]

My valve fell apart on my resent rebuild. followed advice on here to use a screen washer one way valve and all is good.

[MyBongoiscalledDave]

I'm so confused by all this talk of one way valves. Mine doesn't appear to have any stall going to or from the actual EGR valve. I assume, judging by your contributions, that it should have ... ?

We are thinking about the same engine. The 1996 2.5td ...

Does anyone know anything about posting pictures?