Omega Owners Forum

Please login or register.

Login with username, password and session length
Advanced search  

News:

Please play nicely.  No one wants to listen/read a keyboard warriors rants....

Pages: 1 2 [All]   Go Down

Author Topic: strange rpm  (Read 3180 times)

0 Members and 1 Guest are viewing this topic.

Andy A

  • Omega Knight
  • *****
  • Offline Offline
  • Gender: Male
  • Bristol UK
  • Posts: 1101
    • Omega 2.2i CD manual 2003
    • View Profile
strange rpm
« on: 11 May 2017, 12:00:38 »

2003 manual 2.2 petrol.

When I'm travelling down the road at a constant speed of 30mph the engine would lose power for a moment and then gently come back in while keeping the throttle in the same position.
Then the other day it started to do it again, but this time for 2-3 seconds at a time. Some days it doesn't do it at all. There are no codes showing. What could cause this?

Not sure if this is to do with above. The car idles around 1300rpm then slowly drops to below 1000. Lately it has be doing that but as soon as the rpm's go above 2000 they hang there for far too long and it makes changing gear a pain. After less than a minute it hangs for a short time as normal for changing gear smoothly. 

Thanks




« Last Edit: 11 May 2017, 12:06:22 by Andy A »
Logged

omegod

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • liverpool
  • Posts: 4344
    • 2017 Seat Ateca
    • View Profile
Re: strange rpm
« Reply #1 on: 11 May 2017, 12:04:38 »

Could be camshaft sensor starting to break down ( if it's petrol) they don't always show codes and when they do it tends to be for random transmission ones, then again it could be something completely different  :-\
Logged
Happy to do Omega servicing etc around Merseyside,cruise activation, airbag lights sorted too...

Doctor Gollum

  • Get A Life!!
  • *****
  • Offline Offline
  • Gender: Male
  • In a colds and darks puddleses
  • Posts: 28092
  • If you can't eat them, join them...
    • Feetses.
    • View Profile
Re: strange rpm
« Reply #2 on: 11 May 2017, 12:06:23 »

What was the fuel level?
Logged
Onanists always think outside the box.

Bigron

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • Witham, Essex
  • Posts: 4808
    • Omega 2.6 V6 Auto '51 Reg
    • View Profile
Re: strange rpm
« Reply #3 on: 11 May 2017, 12:07:16 »

Omegod beat me, but my answer is probably silly: do you have cruise control, and could it be "having a moment"?

Ron.
Logged

Andy A

  • Omega Knight
  • *****
  • Offline Offline
  • Gender: Male
  • Bristol UK
  • Posts: 1101
    • Omega 2.2i CD manual 2003
    • View Profile
Re: strange rpm
« Reply #4 on: 11 May 2017, 12:08:27 »

What was the fuel level?

It does it on a full tank as well.
Logged

Andy A

  • Omega Knight
  • *****
  • Offline Offline
  • Gender: Male
  • Bristol UK
  • Posts: 1101
    • Omega 2.2i CD manual 2003
    • View Profile
Re: strange rpm
« Reply #5 on: 11 May 2017, 12:09:18 »

Omegod beat me, but my answer is probably silly: do you have cruise control, and could it be "having a moment"?

Ron.

Yes I fitted a cruise control after I got the car.
Logged

Doctor Gollum

  • Get A Life!!
  • *****
  • Offline Offline
  • Gender: Male
  • In a colds and darks puddleses
  • Posts: 28092
  • If you can't eat them, join them...
    • Feetses.
    • View Profile
Re: strange rpm
« Reply #6 on: 11 May 2017, 12:11:28 »

When was the throttle body last cleaned? Worth doing if not done for a while, but it does sound electrical :-\

Incidentally what were the radiator fans doing at the time?
Logged
Onanists always think outside the box.

Andy A

  • Omega Knight
  • *****
  • Offline Offline
  • Gender: Male
  • Bristol UK
  • Posts: 1101
    • Omega 2.2i CD manual 2003
    • View Profile
Re: strange rpm
« Reply #7 on: 11 May 2017, 12:12:34 »

Could be camshaft sensor starting to break down ( if it's petrol) they don't always show codes and when they do it tends to be for random transmission ones, then again it could be something completely different  :-\

Yes it is petrol. I was thinking similar but it is expensive just to try.

I have added some more info to my 1st post.
« Last Edit: 11 May 2017, 12:14:47 by Andy A »
Logged

Andy A

  • Omega Knight
  • *****
  • Offline Offline
  • Gender: Male
  • Bristol UK
  • Posts: 1101
    • Omega 2.2i CD manual 2003
    • View Profile
Re: strange rpm
« Reply #8 on: 11 May 2017, 12:13:55 »

When was the throttle body last cleaned? Worth doing if not done for a while, but it does sound electrical :-\

Incidentally what were the radiator fans doing at the time?

Not sure Al. But the engine temp was good. Why?

Throttle body is still sucking well from the cam cover at idle. If I have this right, would suggest that it is fairly clean?
« Last Edit: 11 May 2017, 12:18:27 by Andy A »
Logged

Andy A

  • Omega Knight
  • *****
  • Offline Offline
  • Gender: Male
  • Bristol UK
  • Posts: 1101
    • Omega 2.2i CD manual 2003
    • View Profile
Re: strange rpm
« Reply #9 on: 11 May 2017, 12:38:41 »

When was the throttle body last cleaned? Worth doing if not done for a while, but it does sound electrical :-\

Incidentally what were the radiator fans doing at the time?

Not sure Al. But the engine temp was good. Why?

Throttle body is still sucking well at idle after pulling hose off the cam cover and stick my thumb over the end. If I have this right, would suggest that it is fairly clear?
Logged

Doctor Gollum

  • Get A Life!!
  • *****
  • Offline Offline
  • Gender: Male
  • In a colds and darks puddleses
  • Posts: 28092
  • If you can't eat them, join them...
    • Feetses.
    • View Profile
Re: strange rpm
« Reply #10 on: 11 May 2017, 13:01:23 »

Sticky throttle butterfly might throw the ecu as it constantly adjusts it even at a set speed on a rolling road... tweaking to compensate for varying load.

Fan question was because them switching on and off will create a current drop/surge, exaggerated by a weak battery or alternator... enough of a drop and the ecu voltages go to cock.

Run through Kevins Starting/Charging guide to rule it out, and make sure all the fans spin freely engine cold and off... don't want to lose a finger if they start automatically... if one is siezed that will have the same effect on the voltage :y
Logged
Onanists always think outside the box.

Andy A

  • Omega Knight
  • *****
  • Offline Offline
  • Gender: Male
  • Bristol UK
  • Posts: 1101
    • Omega 2.2i CD manual 2003
    • View Profile
Re: strange rpm
« Reply #11 on: 11 May 2017, 14:05:42 »

Sticky throttle butterfly might throw the ecu as it constantly adjusts it even at a set speed on a rolling road... tweaking to compensate for varying load.

Fan question was because them switching on and off will create a current drop/surge, exaggerated by a weak battery or alternator... enough of a drop and the ecu voltages go to cock.

Run through Kevins Starting/Charging guide to rule it out, and make sure all the fans spin freely engine cold and off... don't want to lose a finger if they start automatically... if one is siezed that will have the same effect on the voltage :y

Thanks for the info Al, much appreciated.  :y

Will check the fans and go through Kevin's guide and check all is OK.

I will take off the throttle body and clean it again. Only done 2000 miles/a couple of years since last done with brake cleaner. I have just purchased some proper carb cleaner this time, because it has some lubricating properties in it so far as I can tell.
Logged

mandula

  • Junior Member
  • **
  • Offline Offline
  • Gender: Male
  • Finland
  • Posts: 174
    • Opel Omega -03, Z22XE man
    • View Profile
Re: strange rpm
« Reply #12 on: 11 May 2017, 14:49:31 »

I've got similar symptoms (and similar car) with power lose, but only once a month or so. For me, driving with my own leg (not with cruise control I mean ;) ) the car feels to shut down or something, drive just stops for a second and then comes back and drives normally. No codes after that showing. My bet is that there is something wrong with wiring's or connectors between throttle body and pedal.

For high idle, again, I had same symptoms. It was caused by cracked exhaust manifold and leaking pipe joint after 2nd lambda. Fixing those fixed hanging revs, especially when cold engine.
Logged

omegod

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • liverpool
  • Posts: 4344
    • 2017 Seat Ateca
    • View Profile
Re: strange rpm
« Reply #13 on: 11 May 2017, 15:56:32 »

I'm breaking a 2.2 auto that drove fine if you want/need any bit's n bob's
Logged
Happy to do Omega servicing etc around Merseyside,cruise activation, airbag lights sorted too...

Andy A

  • Omega Knight
  • *****
  • Offline Offline
  • Gender: Male
  • Bristol UK
  • Posts: 1101
    • Omega 2.2i CD manual 2003
    • View Profile
Re: strange rpm
« Reply #14 on: 12 May 2017, 17:12:38 »

I'm breaking a 2.2 auto that drove fine if you want/need any bit's n bob's

Do you have an original cam sensor?
Logged

omegod

  • Omega Baron
  • *****
  • Offline Offline
  • Gender: Male
  • liverpool
  • Posts: 4344
    • 2017 Seat Ateca
    • View Profile
Re: strange rpm
« Reply #15 on: 12 May 2017, 22:38:08 »

I'm breaking a 2.2 auto that drove fine if you want/need any bit's n bob's

Do you have an original cam sensor?

Yup
Logged
Happy to do Omega servicing etc around Merseyside,cruise activation, airbag lights sorted too...

Andy A

  • Omega Knight
  • *****
  • Offline Offline
  • Gender: Male
  • Bristol UK
  • Posts: 1101
    • Omega 2.2i CD manual 2003
    • View Profile
Re: strange rpm
« Reply #16 on: 14 May 2017, 09:45:57 »

I've got similar symptoms (and similar car) with power lose, but only once a month or so. For me, driving with my own leg (not with cruise control I mean ;) ) the car feels to shut down or something, drive just stops for a second and then comes back and drives normally. No codes after that showing. My bet is that there is something wrong with wiring's or connectors between throttle body and pedal.

For high idle, again, I had same symptoms. It was caused by cracked exhaust manifold and leaking pipe joint after 2nd lambda. Fixing those fixed hanging revs, especially when cold engine.

When I last had the MOT done in March there was an advisory. Rear Exhaust has a minor leak of exhaust gases (7.1.2). If this got worse could it be causing the high revs?
Logged

mandula

  • Junior Member
  • **
  • Offline Offline
  • Gender: Male
  • Finland
  • Posts: 174
    • Opel Omega -03, Z22XE man
    • View Profile
Re: strange rpm
« Reply #17 on: 14 May 2017, 12:36:23 »

I've got similar symptoms (and similar car) with power lose, but only once a month or so. For me, driving with my own leg (not with cruise control I mean ;) ) the car feels to shut down or something, drive just stops for a second and then comes back and drives normally. No codes after that showing. My bet is that there is something wrong with wiring's or connectors between throttle body and pedal.

For high idle, again, I had same symptoms. It was caused by cracked exhaust manifold and leaking pipe joint after 2nd lambda. Fixing those fixed hanging revs, especially when cold engine.

When I last had the MOT done in March there was an advisory. Rear Exhaust has a minor leak of exhaust gases (7.1.2). If this got worse could it be causing the high revs?

Don't know, but i quess that if only the rear exhaust has a leak, it should not mess up the idle. Mine was just near 2nd lambda and it really made idle messy.

I bet that if you take off the exhaust manifold cover there is a big crack on manifold (if still original). That wont show on MOT, or at least not at my case, but will cause revs to hang.
« Last Edit: 14 May 2017, 12:38:36 by mandula »
Logged

Andy A

  • Omega Knight
  • *****
  • Offline Offline
  • Gender: Male
  • Bristol UK
  • Posts: 1101
    • Omega 2.2i CD manual 2003
    • View Profile
Re: strange rpm
« Reply #18 on: 15 May 2017, 09:24:18 »

I've got similar symptoms (and similar car) with power lose, but only once a month or so. For me, driving with my own leg (not with cruise control I mean ;) ) the car feels to shut down or something, drive just stops for a second and then comes back and drives normally. No codes after that showing. My bet is that there is something wrong with wiring's or connectors between throttle body and pedal.

For high idle, again, I had same symptoms. It was caused by cracked exhaust manifold and leaking pipe joint after 2nd lambda. Fixing those fixed hanging revs, especially when cold engine.

When I last had the MOT done in March there was an advisory. Rear Exhaust has a minor leak of exhaust gases (7.1.2). If this got worse could it be causing the high revs?

Don't know, but i quess that if only the rear exhaust has a leak, it should not mess up the idle. Mine was just near 2nd lambda and it really made idle messy.

I bet that if you take off the exhaust manifold cover there is a big crack on manifold (if still original). That wont show on MOT, or at least not at my case, but will cause revs to hang.

When the rain stops I'll take the shield off and have a look.  :y Did notice when I bought the car years ago the shield had a bolt snapped off/missing.
Logged

Andy A

  • Omega Knight
  • *****
  • Offline Offline
  • Gender: Male
  • Bristol UK
  • Posts: 1101
    • Omega 2.2i CD manual 2003
    • View Profile
Re: strange rpm
« Reply #19 on: 22 July 2017, 17:05:14 »

There was a crack in the exhaust manifold under the heat shield and with one bolt already snapped off before I got the car, I guess it can stay that way until it fails the MOT.
Thanks all for your help.  :y
Logged
Pages: 1 2 [All]   Go Up
 

Page created in 0.045 seconds with 18 queries.