glowplugs,vacuum switches and broken plastic !

[cookan]

Hi guys,
I have found 2 problems (wehheey) and made 1 problem (booo) today and could do with some advice...

1. My 95 diesel auto 2wd has been rough to start from cold the last few weeks...it throws out a bit of black smoke and misses for about 20-30 seconds before idling normal and clean so I thought I'd take a look at the glow plugs today. Having pulled back the bracket with the relays on, I found the the second glow plug from the left is no longer attached to the rail..the top thread is sheered off. I'm hoping that's the cause so would like to replace it..having not done this before I was hoping I could just remove the relay bracket but not sure what the easiest way to remove that is...lots of hardened vacuum pipes I'm not sure will come off (see point 3!). Is removal of the top engine cover the way to go or should I attempt to disconnect sufficient pipes from the relays to get the whole 'stay'/bracket out of the way ?

2. With some further detective work I also found this....



I thought maybe EGR related but having read the glow plug factsheet now think it's one of the things that's supposed to switch the glow plugs off when being driven..Anyone know what this is called and where I might get one ?

3. Now for the problem I created...thought I'd try to pull the vacuum pipe off to get a closer look at that green valve and the other end then thing snapped straight off the air intake hose that goes round the back of the engine to the turbo.. it's the nipple labelled 1375/93-5104 in the middle of this diagram.. http://lushprojects.com/bongopartsmk2/c ... mgno=.html

I think I first option here is to try gluing it back on to the air intake and getting some new lengths of 'supple' vacuum pipe to refit unless anyone has any other suggestions..

thanks,
Ant.

[wonkanoby]

take the tunnel out and do all 4

[Coradia63]

Hi Cookan,

I had the same problem the green non-return valve had snapped one side and when I pulled the pipe from the air intake it snapped the fitting off I originally glued it using a specific super glue for plastics worked for a while but broke off again so I have got a fuel tank fitting from a local model shop drilled out the air intake slightly smaller than thread on the fitting and managed to screw it straight in I put a bit of super glue on for good measure similar to the fitting show in the link

http://www.avicraft.co.uk/field-equipme ... x-10-.html

You could use the nut on the inside of the air intake but if it worked loose and got sucked into the engine wouldnt be to good

as for the non-return valve I managed to super glue it back together but will need to get a replacement soon as I dont expect it to last..

Cheers
Suart

[Northern Bongolow]

you could use the valve off a cycle tube,(the racing type, that is thin), bolt that through the air pipe to the turbo.

the green valve is a one way valve, these are on all mazda's both petrol and diesels, with egr fitted. they are on lots of other cars too so any good car factors will have them. just fit it the correct way round . the pipe needed is the thick wall vac pipe, if its too thin in will collapse under vac when warm. i was messing with one today that was so well baked the pipes shattered when touched. remove the solenoid bracket and replace all the pipework BUT BE CAREFUL THE NIPPLES ON THE SOLENOIDS BREAK OFF TOO IF ROUGHLY HANDLED.

[cookan]

excellent, thanks guys..always good to know someone else has worked through the same problem ! Think that pretty much covers all my questions too ! I'm planning an early start tomorrow to get the engine cover off and try to replace the obviously bust glow plug..I'll test the others in situe at the same time..my 1/4inch sockets just about fit over the glow plug head if I don't push the extension all the way into the socket so hoping I'll get away without a deep drive. The previous owner also left me the previous set of plugs but in that bundle was a shiny new one also..measures 1ohm and has never been fitted so hoping 1 swap will do the trick.

Then planning a trip to the local whoopee to try and get some vacuum hose..I'll take the check valve with me on the off-chance they have something to match. On line it looked like 40-50 quid which is daft, so good to know they should be easier to come buy than getting that specific part number.
I'll try the plastic epoxy on the broken nipple first, and order a screw in nipple for later. The nipple came adrift from the air hose with it's little circular base intact..looked almost like the original weld didn't take so rather than trying to glue just the shaft of the nipple, I've got a larger base to work with so hopefully will hold a while.

Think i'll cut the hose off the solenoid and check valve..just been trying to gently prize the remaining end off the check valve and it won't budge with heat, dw40 or screwdrivers without risking busting the other end !

I'll report back ! (most likely mid-job ;-( )

thanks,
Ant.

[v8griffith]

Hi
I had exactly the same thing happen to me. When I first got my bongo I noticed the pipe was broken at the solenoid end so I tried to cut the end off so I could push it back on the solenoid but it just shattered so I tried to pull it off the green valve but it came away from the air intake snapping the stub off the intake I managed to glue the stub back on to the intake with super glue but the green valve was also damaged. I managed to get some thick walled tubing which I connected from the intake to the solenoid missing out the green valve but when the engine warmed up I lost loads of power and there was lots of black smoke from the exhaust. I have not been able to get a new valve anywhere but when I disconnected the tube again the engine seemed to run fine.

My question is... Is this valve necessary? Will it cause any problems running without it?

Ken n Moira

[cookan]

I'd like to know that too..the valve (at least on mine) is pointing upwards which allows air out of the air intake INTO the solenoid..so unless my valve was the wrong way round, it would seem to me it has positive pressure in it either constantly, or intermittently depending on the difference between the amount of air coming into the intake and the speed of the engine, but never negative..the change from pressure, to no pressure must trigger the solenoid and I believe that is 'one' of the things that can switch the glow plugs off (at least until the coolant temperature takes over)...so I imagine the glow plugs stay on longer without this pipe in place...but with the pipe connected without the check valve a change of pressure could, I presume pull/push the solenoid the wrong way and damage it...that would be my logic anyway..and beware, I'm just making stuff up as I go along in the hope that someone who actually knows what they're doing will step in !

Anyway, I'm done on the glow plugs..not bad by 8am for an amateur eh ? I also found the reason for the shiny new spare glowplug in the bundle the previous owner gave me....the one I thought was sheered off was actually an old 'short' glowplug that was broken in situe so the head was below the rail making it look like just the top thread was sheered off..in fact the plug just spins as per numerous other threads on that subject. I tested the others in situe which are all the 'long' versions and found number 3 was open circuit so replaced it and the bongo started much much better...chuffed for maybe 3-4 seconds instead of 30-40. So happy with that !

Now I'm off to wake up the motor factors to try to get some pipe, and some glue ! as possibly a valve..

Ant.

[wonkanoby]

if its been altered from short to long plugs check carefully the link bit cannot touch and short on any thing

[Northern Bongolow]

the little valve has no effect on the glow plugs at all.
it allows a vac to be held in the cold start solenoids and the egr solenoids when its in the warm up cycle--ticking over. when the engine is revved the vac is overcome and the vac in the solenoids is lost into the turbo airpipe. the vac for warm up isnt needed when your working the engine.
so in normal running the lack of the valve isnt important, but it will be missed during warm up and egr switching,but if the egr is blanked off, no worries

[cookan]

thanks for the clarification ! I'd read on the fact sheet on the last page that there was a vacuum switch fitted in the turbo induction pipework that switches the glow plugs off so assumed that's what it was.

I've glued the check valve and the nipple on the air intake now anyway...going to let it cure over night before refitting the vacuum pipes. Just about managed to get some 4mm pipe....it's thicker walled and perhaps slightly larger internal diam..but feels tight enough on the nozzles. I also stopped by a scrappy and phoned a few others...no mazdas in any of them for some reasons but I did yank a 1 way valve off the top of an audi..it's a bit heavier to operate but I'm sure it'll do the trick if I need one temporarily...and it was £43 cheaper than the mazda garage.

fingers crossed for the glue anyway ! One thing I did notice was that this nipple is actually fitted into the intake kind of like a plastic version of a rivet. As opposed to being just welded onto the outside of the intake as I thought it was, these seem to be inserted into the intake then melted over from the inside so you're actually left with something that could potentially drop off inside when the nipples break off from the outside..the remains of mine seemed secure where it was but I'd advise people check inside the intake if doing this job to make sure there aren't remnants of the nipple head coming loose.

Ant.

[cookan]

so...both of my glue attempts have already failed ;-( thought I'd done a pretty strong job too !

Ordered some brass nipples to screw in this time as per Stuarts suggestion above..hope these fit my hose...

http://www.ebay.co.uk/itm/2-NIPPLES-M4- ... 23242db707

I'll try gluing the one way valve again..this time I'll rough the surfaces up.

Ant.