Vacuum control Valve ????

Technical questions and answers about the Mazda Bongo

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slim

Vacuum control Valve ????

Post by slim » Thu Jan 21, 2010 7:56 pm

I have had the cylinder head replaced and my Bongo is still spewing out white exhaust in the morning and rumbling slightly more than it did before the replacement, this only happens in the morning, the rest of the day it starts fine.

I took it back to the garage as felt wasn't quite right and the mechanic has told me it has a damaged vacuum control valve? He has upped the idle to stop the vibration but this hasn't really made any difference and still spewing exhaust. Not quite sure what to think as my knowledge of mechanics is limited. A friend told me he is bluffing and has probably made a hash of replacing cylinder head. Not sure what to think...Has anyone got any answers...Should I get new Vaccuum Control Valve and can anyone tel me what it is/does. PS Also had glow Plugs checked and they seem to be ok.

Cheers S
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dandywarhol
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Re: Vacuum control Valve ????

Post by dandywarhol » Thu Jan 21, 2010 9:20 pm

Hi S, there's a vacuum control valve which lifts the idle speed when warming up - like a fast idle device. If it is faulty (could be a faulty valve /soleniod/pipe) then the engine will idle roughly until warm. I'm surprised he didn't fix that when he did the head - that job is expensive enough - the valve shouldn't cost much to sort.

As for white smoke - shouldn't still be doing it but there will be some vapour in these cold mornings.

Are the heaters working ok?
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slim

Re: Vacuum control Valve ????

Post by slim » Thu Jan 21, 2010 9:45 pm

Hi DW,
Thanks for your reply.
What I would have expected too...he'd fix the problem before returning vehicle to me especially as it wasn't like it before.
Yep Heater seem to be fine... guess I should go for the vacuum fix then?

Slim
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dandywarhol
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Re: Vacuum control Valve ????

Post by dandywarhol » Fri Jan 22, 2010 12:14 am

Yep - the same solenoid raises the rpm when the air con is switched on - lightly place your foot on the throttle and switch on the a/c - the pedal should drop slightly
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Re: Vacuum control Valve ????

Post by slim » Sat Jan 23, 2010 11:42 am

Hi DW,
Just read your reply.
Did as you suggested with a/c and throttle but didn't notice peddle drop slightly. Does that indicate a problem with the vaccuum pump and if so any ideas where I might get one for the Bongo? Vehicle is still throwing out loads of white exhaust in morning too. Would like to get problem fixed before next weekend as we're off on a Bongo jaunt to Bristol.

Cheers Slim
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Re: Vacuum control Valve ????

Post by dandywarhol » Sat Jan 23, 2010 12:46 pm

Unlikely to be the vac pump as it also gives you the necessary brake boostlike a petrol car brake servo :? More likely to be a broken solenoid/pipe/wire. The solenoid is one of the 2 sitting side by side on a bracket to the rear of the cylinder head under the driver's seat - look for a broken pipe.....................................
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Re: Vacuum control Valve ????

Post by slim » Thu Jan 28, 2010 11:26 am

Hi. Thanks for reply. Just checked under drivers seat and could not find broken solenoid pipes but evidence of leaking coolant from hose coming from cylinder head. Would this be the most likely reason for the exhaust & spluttering? Not sure what to do about approaching mechanic as noticed the other day the seals under front of bongo had been crushed, obviously where it had been jacked up & wondering what else will go wrong if I take it back to him. Should I complain?

Cheers Slim.
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Re: Vacuum control Valve ????

Post by wonkanoby » Thu Jan 28, 2010 11:44 am

do you mean cills.................not sure where a seal would be
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Re: Vacuum control Valve ????

Post by missfixit70 » Thu Jan 28, 2010 3:19 pm

slim wrote:Hi. Thanks for reply. Just checked under drivers seat and could not find broken solenoid pipes but evidence of leaking coolant from hose coming from cylinder head. Would this be the most likely reason for the exhaust & spluttering? Not sure what to do about approaching mechanic as noticed the other day the seals under front of bongo had been crushed, obviously where it had been jacked up & wondering what else will go wrong if I take it back to him. Should I complain?

Cheers Slim.
Complain about the sills by all means, but do not drive it with a leaking coolant hose, that could end up a very expensive trip. If it overheats you could be looking at a new head. Has it overheated already, what is the coolant level like? have you had to top it up? Get it sorted asap & make sure it's bled properly, instructions in the members area, there is also a list of bongo friendly garages, i wouldn't trust anyone who doesn't know bongos to work on the coolant system.
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slim

Re: Vacuum control Valve ????

Post by slim » Thu Jan 28, 2010 4:11 pm

Hi K, Thanks for post. Yes sills not seals! underside of front doors. And yes had cylinder head replaced but since then bongo throws out exhaust and doesn't like starting in morning. Mechanic told me it was idle-ing too high due to broken vacuum control valve but I'm inclined not to believe him. think he hasn't finished job properly.
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Re: Vacuum control Valve ????

Post by missfixit70 » Thu Jan 28, 2010 4:14 pm

#-o I shoulda gone back & read the first post again :wink: Get it back to him & get it sorted properly, I don't think the vacuum control valve is the problem TBH.
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Re: Vacuum control Valve ????

Post by Tur80 » Thu Jan 28, 2010 10:07 pm

If all was ok prior to the work being done, it's possible that either

1.not all of the vacuum pipes have been reconnected,
2. they have been incorrectly reconnected, or
3. have been damaged whilst working on the head.
A couple of mine have gone brittle and broke whilst replacing the head.

The white smoke and bad running could be one or more glowplugs have failed.
Ensure all solenoids have been reconnected! :oops:

These are a couple of problems I've had, hope it helps

Fingers crossed :D
slim

Re: Vacuum control Valve ????

Post by slim » Sat Jan 30, 2010 2:36 pm

Thanks for all the replies. I had a look for broken pipes etc but didn't notice anything apart from leaking coolant from main hose leaving head under drivers seat. So went back to mechanic and he took pipe off and refitted it, but did not bleed coolant for air locks...should he have done this?

I enquired again about starting problem in morning and he said that bongo should be fine as he had adjusted the rev, wasn't happy with his answer but left and had another look for broken pipe etc this morning and notice that a pipe was indeed left off what i believe to be a solenoid. Anyway fitted it back in place an now bongo is revving whilst stationary at 2 and around the same when in neutral but jumps when put into drive which feels quite dangerous. any ideas on how to lower revs as I'm no mechanic and want to go back to the same garage for fear of more trouble!

cheer
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Re: Vacuum control Valve ????

Post by missfixit70 » Sat Jan 30, 2010 2:54 pm

You're saying he removed & refitted a leaky coolant hose without bleeding & he's basically increased the revs to 2000rpm? What a pillock.
It needs bleeding if the coolant has been messed with, & increasing the stationary revs like that is just ridiculous, I'd suggest you get it to another bongo friendly garage, get them to check what's going on, but if it hasn't been bled, I wouldn't be happy driving it. Did you tell him about bleeding it? Have you checked to see if the coolant level is ok & the heaters are working? Was the coolant leaking form the pipe itself, ie does it really need replacing with a new one?
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Re: Vacuum control Valve ????

Post by jaylee » Sat Jan 30, 2010 3:07 pm

Got to agree with Kirsty on the mechanic.. Looks like he removed the symptom, but NOT the cause..?

If i were you, i would take my vehicle back to that garage for one reason only. Get the guy to fix yer damaged sills! :wink:

You mentioned something about Bristol.. Where are you roughly located?
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