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Author Topic: Engine running OK but feels 'flat', I think the vacuum powered flaps not working  (Read 4916 times)

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malcy_p

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Hello again!

Not been in here for ages - but I still love and cherish my last Omega (a 2.6 auto, 2003).

Anyway, she's been good for years, but now she has a problem. From what I can work out the problem is that the vacuum powered 'flaps' in the induction tract are not working. I've pulled and examined the various vacuum pipes (large and small) from the manifold to the brake servo etc. and they look good, the rubber joiners are fine etc.

I guess someone has come across this before, but if the vacuum isn't reaching the valves, what is the best test?

  • Should I remove the vacuum box and suck/blow (fnarr!) down the pipes?
  • What does this feel like?
  • Do these items often fail?
  • Is there an clearly marked 'in' and 'out' for the testing?

If any of you wonderful people could point me in the right direction, I'll be very grateful...  :)

/malc.
« Last Edit: 17 August 2018, 20:47:18 by malcy_p »
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terry paget

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Hi Malc, great to hear from you again.
As I expect you are aware, there are 2 dual ram devices on the Omega V6s, one in the bagpipes and one in the plenum. If a valve is stuck open the engine will seem 'flat' at low and medium rpm. They open at quite high rpm, I think there is a guide in the maintenance section. They can stick, too, in which case removal and cleaning and oiling will effect a cure. Both get their vacuum from the reservoir at the bottom the bagpipes, and are switched on and off by electric switches.
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malcy_p

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 :) Hello Terry - long time no speak but great to 'see' you on line again!  :D

I'll have another look at the problem tomorrow, but I'd spent an hour or so reading stuff on here - I think I've learned a lot so far.

Quick question - am I saying the right thing in this image?? :) 



Thanks.
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terry paget

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malcy_p

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terry paget

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:) Hello Terry - long time no speak but great to 'see' you on line again!  :D

I'll have another look at the problem tomorrow, but I'd spent an hour or so reading stuff on here - I think I've learned a lot so far.

Quick question - am I saying the right thing in this image?? :) 



Thanks.
Just had a quick look at my 2.5. Vacuum goes into the reservoir on the RH pipe and goes to the rams by the LH pipe, opposite way to your picture. I think there is a valve in the resevoir, so it matters.
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terry paget

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:) Hello Terry - long time no speak but great to 'see' you on line again!  :D

I'll have another look at the problem tomorrow, but I'd spent an hour or so reading stuff on here - I think I've learned a lot so far.

Quick question - am I saying the right thing in this image?? :) 



Thanks.
Just had a quick look at my 2.5. Vacuum goes into the reservoir on the RH pipe and goes to the rams by the LH pipe, opposite way to your picture. I think there is a valve in the resevoir, so it matters.
Just checked my other 2.5. The hose from the manifold goes into the outside (wing) pipe on the reservoir. Answer to your picture arrows is NO.
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terry paget

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Woops! I read in the maintenance guide V6 vacuum pipes section that the vac reservoirs both have thicker input pipes, as in your picture.
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terry paget

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I have just swopped my dual ram reservoir pipes over, and it made no obvious difference.
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malcy_p

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Hi Terry - Have just unplugged-re-plugged all the small vacuum pipes, re-routed them, running better but just going for a test time... will be back soon! :)
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malcy_p

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Hi Terry - Have just unplugged-re-plugged all the small vacuum pipes, re-routed them, running better but just going for a test time... will be back soon! :)

Afternoon all - just from visiting my dear old mother (the 87 years old girl!) and the Omega *is* running smoother than before - but I still think that the multiram valves operation gave a more noticeable change to the engine note when they operated... Will investigate again later.

/m.
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malcy_p

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Evening all & Terry! :)

Right - I've just spent an hour of so looking that the problem.

First of all, I swapped the in and out of the vacuum box around - as you said Terry, little change! Put it back to normal.  ::)

Next I got SWMBO to sit in the driving seat and do the pedals. We tried all the rev ranges, nothing at all happened with any of the valves, nothing! :(

So, removed the pipe section and sucked/blew into the vacuum box... Then I sucked on the 'in' port no vacuum was presented at the 'out' port. It's dead.   :'(

Trying something different, I put everything back to together and totally bypassed the vacuum box... Tick over was much better! :D

Got SWMBO to dance on the pedals again, and this time the resonance valve at the back worked as expected, but the front intake valve didn't move at all.

I've ordered a vacuum box, should I expect the intake valve to work better with a working box in line? If not, anyone know the part number of the intake valve vacuum control - or anyone have one for sale? :)

Thanks guys. :)
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terry paget

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Your pipe suggestion is correct, my cars are both wrong. I tested 2 spare reservoirs as follows. I blew compressed air in one side and on the other side I attached a hose ending in a jar of water. In both cases blowing in the right hand pipe produces lots of bubbles from the LH pipe. The other way nothing happened. Conclusion: Air goes from RH to LH pipes, so we need to suck on the LH pipe to draw air in the RH pipe. As the maintenance guide article says.
I shall now switch mine over. Funny, mine were running fine before.
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Shackeng

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Your pipe suggestion is correct, my cars are both wrong. I tested 2 spare reservoirs as follows. I blew compressed air in one side and on the other side I attached a hose ending in a jar of water. In both cases blowing in the right hand pipe produces lots of bubbles from the LH pipe. The other way nothing happened. Conclusion: Air goes from RH to LH pipes, so we need to suck on the LH pipe to draw air in the RH pipe. As the maintenance guide article says.
I shall now switch mine over. Funny, mine were running fine before.

Let us know Terry. ::) :y
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Mr Gav

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Evening all & Terry! :)

Right - I've just spent an hour of so looking that the problem.

First of all, I swapped the in and out of the vacuum box around - as you said Terry, little change! Put it back to normal.  ::)

Next I got SWMBO to sit in the driving seat and do the pedals. We tried all the rev ranges, nothing at all happened with any of the valves, nothing! :(

So, removed the pipe section and sucked/blew into the vacuum box... Then I sucked on the 'in' port no vacuum was presented at the 'out' port. It's dead.   :'(

Trying something different, I put everything back to together and totally bypassed the vacuum box... Tick over was much better! :D

Got SWMBO to dance on the pedals again, and this time the resonance valve at the back worked as expected, but the front intake valve didn't move at all.

I've ordered a vacuum box, should I expect the intake valve to work better with a working box in line? If not, anyone know the part number of the intake valve vacuum control - or anyone have one for sale? :)

Thanks guys. :)

If you can`t get vacuum reservoir then you could try a one way non return valve, the type used in fish tanks, I did this on my Senator when the vacuum box packed up and they were NLS.
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