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[terry paget]

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.

I found X168 was already correct - that's the car I have been mending for the last 2 weeks. V828 was wrong, so I corrected it. It drives fine, but it drove fine before; there was no tremendous improvement.

[terry paget]

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!

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.

If they are NLS PM me your address and I will post you one.

[terry paget]

I expect you have read that the front ram opens at 3400rpm, and the plenum ram is open at idle ( certainly on earlier models with the idle control valve), then closed until 4100rpm, when it opens again. I do not know at what rpm the 'fly by wire' Omega rams open, prpbably the same at high revs, but the plenum ram  closed at idle.

[Doctor Gollum]

About 3k for one end and 4k for the other, but can't recall which is which... Certainly by 4.2k both should be open

[terry paget]

If the reservoir valve is working normally, or stuck open, it hardly matters, either way vacuum will get through and operate the ram. Only if stuck shut will it affect operation. This explains why correcting incorrect plumbing on V828 made no difference.
If your car seems 'flat' you must have a ram stuck open. I have known that. Most of the while we are below 4000rpm, when plenum ram should be closed.

[malcy_p]

Hi Terry,

I had a new(er) vacuum reservoir arrive yesterday - will try fitting it in the next few days. Time will tell!

/malc.

[terry paget]

Hi Terry,

I had a new(er) vacuum reservoir arrive yesterday - will try fitting it in the next few days. Time will tell!

/malc.

I had a 'flat' car and the plenum ram was stuck open. After many checks I established this fact, took it out, cleaned it, and then it worked. It opens at 4200rpm, which is quite fast when you have your head stuck under the bonnet while your wife opens the throttle.
Has this suddenly gone flat?  I only discovered I had flat cars by comparison with similar cars. My first Senator was flat, and I would never have known had I not bought a second one that was not.

[malcy_p]

Terry - hope you're ok. Sorry for the delay, been on hols over the last week.

Today I looked at the vacuum. Fitted the new vacuum reservoir box - tested it first, all OK. If you block the small bore connection and suck on the large bore connection and let go, then unblock the smaller connection you hear the fisss from the stored vacuum from the small port.

After checking the rubber pipe joints I also saw a crack on the 90 degree joint by the front intake pipe, so replaced it with a spare...

Went for a short test drive - all seems OK and go SWMBO in the driving seat and watched the values as she rev'ed the engine. Hmmm. The rear resonance valve opened fine but I didn't see the front one move. Boo. Took the vacuum valve off and tested it electrically - it works. Ran out of time this evening - boy it is getting dark earlier now!! :/

Off to work tomorrow, with see how she's driving, but has someone else seem the front intake valve opening when you are under the bonnet? Is it just me or other people too?

Thanks Terry & guys.

/malc.

[Raeturbo]

Yes I’ve seen the front one opening

[malcy_p]

Yes I’ve seen the front one opening

Rats.... Off to work now, will see how things are later on.

/m.

[terry paget]

Does it seem flat above 4200rpm? My idea of flat feel occurs at low or medium rpm, when the dual ram valves should be shut.
Of course the fault could be electric, though it should throw up a warning message.

[Doctor Gollum]

There is a thorough guide to the multi ram system in the FAQs

[malcy_p]

  It is all working...! 

I disconnected & blew through all the vacuum pipes & I can hear & feel the engine change just over 4k revs... Yay!

Thanks for the help guys, & now that's sorted I've spent a few quids on new brake disks, pads, caliper slides & a front bearing to fettle the front end of the car.

Another thing I think will need sorting is the headlight aim - seems too high & some other drivers are flashing me on dipped beam

Thanks again

/malc.

[terry paget]

Congratulations!
If it happens over 4000rpm it must have been the plenum dual ram not functioning.
I suspect you, like me, get ever more desperate to cure the fault, and change several things on each dismantling and reassembly, then suddenly and happily curing the fault you cannot be sure which change put things right.