Omega Owners Forum

Please login or register.

Login with username, password and session length
Advanced search  

News:

Please check the Forum Guidelines at the top of the Newbie section

Pages: 1 [2]  All   Go Down

Author Topic: Engine running OK but feels 'flat', I think the vacuum powered flaps not working  (Read 4919 times)

0 Members and 1 Guest are viewing this topic.

terry paget

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • Midsomer Norton Somerset
  • Posts: 4633
    • 3 Astras 2 Vectra
    • View Profile

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
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.
Logged

terry paget

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • Midsomer Norton Somerset
  • Posts: 4633
    • 3 Astras 2 Vectra
    • View Profile

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

terry paget

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • Midsomer Norton Somerset
  • Posts: 4633
    • 3 Astras 2 Vectra
    • View Profile

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.
Logged

Doctor Gollum

  • Get A Life!!
  • *****
  • Offline Offline
  • Gender: Male
  • In a colds and darks puddleses
  • Posts: 28089
  • If you can't eat them, join them...
    • Feetses.
    • View Profile

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 :y
Logged
Onanists always think outside the box.

terry paget

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • Midsomer Norton Somerset
  • Posts: 4633
    • 3 Astras 2 Vectra
    • View Profile

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.
Logged

malcy_p

  • Junior Member
  • **
  • Offline Offline
  • Gender: Male
  • Suffolk
  • Posts: 106
  • 2.6 MV6 Estate
    • View Profile

Hi Terry,

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

/malc.
Logged

terry paget

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • Midsomer Norton Somerset
  • Posts: 4633
    • 3 Astras 2 Vectra
    • View Profile

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.
Logged

malcy_p

  • Junior Member
  • **
  • Offline Offline
  • Gender: Male
  • Suffolk
  • Posts: 106
  • 2.6 MV6 Estate
    • View Profile

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.
Logged

Raeturbo

  • Omega Lord
  • *****
  • Offline Offline
  • Gender: Male
  • South Wales
  • Posts: 7278
    • Mv6 3.2 Mitsi Evo2. XJ8
    • View Profile

Yes I’ve seen the front one opening
Logged
Laying a rubber road.

malcy_p

  • Junior Member
  • **
  • Offline Offline
  • Gender: Male
  • Suffolk
  • Posts: 106
  • 2.6 MV6 Estate
    • View Profile

Yes I’ve seen the front one opening

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

/m.
Logged

terry paget

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • Midsomer Norton Somerset
  • Posts: 4633
    • 3 Astras 2 Vectra
    • View Profile

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.
Logged

Doctor Gollum

  • Get A Life!!
  • *****
  • Offline Offline
  • Gender: Male
  • In a colds and darks puddleses
  • Posts: 28089
  • If you can't eat them, join them...
    • Feetses.
    • View Profile

There is a thorough guide to the multi ram system in the FAQs ;)
Logged
Onanists always think outside the box.

malcy_p

  • Junior Member
  • **
  • Offline Offline
  • Gender: Male
  • Suffolk
  • Posts: 106
  • 2.6 MV6 Estate
    • View Profile

 :D :D :D It is all working...!  :D :D :D

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.
Logged

terry paget

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • Midsomer Norton Somerset
  • Posts: 4633
    • 3 Astras 2 Vectra
    • View Profile

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.
Logged
Pages: 1 [2]  All   Go Up
 

Page created in 0.041 seconds with 21 queries.