Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: bigclive on 07 April 2011, 21:19:49

Title: omega bogging down + revving by itself
Post by: bigclive on 07 April 2011, 21:19:49
Hi, I have a 1998 2l auto omega which bogs down intermittently under hard acceleration, then when hot, revs up and down on idle in park. I have just done the full IACV and Breather Jet clean by following the guide I found on this forum. New plugs were fitted 500 miles ago but it seems to be missing badly at times and power delivery is uneven under acceleration. Has this happened to someone else that could maybe advise me how to fix this please?
Title: Re: omega bogging down + revving by itself
Post by: Abiton on 07 April 2011, 21:34:13
Could be a leak of unmetered air (i.e. after the MAF) causing this behaviour. 
Check breather hoses, vac hoses and inlet plastic trunking on the way to the throttle body for splits or cracks. Don't forget the big vac hose going to the brake servo from low down on the inlet manifold.

This can be done visually, by touch, or probably best of all by spraying carb cleaner locally in one area after another of the engine bay, listening for a change in revs associated with the carb cleaner being sucked in and burned.

Good luck with it.  :)
Title: Re: omega bogging down + revving by itself
Post by: Entwood on 07 April 2011, 21:39:51
Was the problem there before you did the breather clean .. or has it appeared after ???

If after then its more likely to be something you've not reconnected properly, or the plenum is not seated properly.

HTH  :)
Title: Re: omega bogging down + revving by itself
Post by: bigclive on 07 April 2011, 21:45:08
Quote
Was the problem there before you did the breather clean .. or has it appeared after ???

If after then its more likely to be something you've not reconnected properly, or the plenum is not seated properly.

HTH  :)

no, the problem was there before I started, apart from the revving up, which has happened before but not recently, and now its back lol
Title: Re: omega bogging down + revving by itself
Post by: RobG on 07 April 2011, 22:37:12
Quote
Was the problem there before you did the breather clean .. or has it appeared after ???

If after then its more likely to be something you've not reconnected properly, or the plenum is not seated properly.
HTH  :)
4-pot Nige ;)
Title: Re: omega bogging down + revving by itself
Post by: Entwood on 07 April 2011, 22:38:19
Quote
Quote
Was the problem there before you did the breather clean .. or has it appeared after ???

If after then its more likely to be something you've not reconnected properly, or the plenum is not seated properly.
HTH  :)
4-pot Nige ;)


DOH .... :(

Methinks those with only 2/3rds an engine should be forced to post in red !!!!   :)
Title: Re: omega bogging down + revving by itself
Post by: RobG on 07 April 2011, 22:41:40
Quote
Quote
Quote
Was the problem there before you did the breather clean .. or has it appeared after ???

If after then its more likely to be something you've not reconnected properly, or the plenum is not seated properly.
HTH  :)
4-pot Nige ;)


DOH .... :(

Methinks those with only 2/3rds an engine should be forced to post in red !!!!   :)
......and those with 6-pots, given the inordinate amount of time they spend under the bonnet they should know enough not to post at all ;D ;D ;D
Title: Re: omega bogging down + revving by itself
Post by: Abiton on 07 April 2011, 22:44:22
Well said Rob. 

V6 = 1.5 times as many problems, at least, as far as I can make out.
Title: Re: omega bogging down + revving by itself
Post by: Xenon on 08 April 2011, 11:39:11
Quote
Quote
Quote
Was the problem there before you did the breather clean .. or has it appeared after ???

If after then its more likely to be something you've not reconnected properly, or the plenum is not seated properly.
HTH  :)
4-pot Nige ;)


DOH .... :(

Methinks those with only 2/3rds an engine should be forced to post in red !!!!   :)
Methinks you should just read peoples questions more carefully. :y
Title: Re: omega bogging down + revving by itself
Post by: duggs on 08 April 2011, 12:49:37
Nope ! V6's have more things to fiddle with, to help keep more busy and occupied in old age !

I had the same problems as yourself with my real man's engine...the dis pack was flubbered !
Title: Re: omega bogging down + revving by itself
Post by: bigclive on 08 April 2011, 12:55:15
hi everyone, I will cheak everything that has been mentioned today and report back, I am also changing the fuel filter today to see if that helps, as im not sure its ever been changed since the car was made lol.
Title: Re: omega bogging down + revving by itself
Post by: bigclive on 13 April 2011, 14:12:47
Hi again, I have checked all pipes etc,, and could not find any problems, fuel filter has been changed, mass air flow has also now been changed for a second hand one from ebay (I broke the original one when cleaning it lol, but i did think that the one i broke may of been faulty anyway)
I have also now done the paper clip trick to obtain error codes, and i get 4 codes which are:
0-2-3-0      Fuel Pump Relay Voltage High/low
0-5-0-5      Idle Air Control Voltage High/low
0-1-0-0      Mass Air Flow Sensor Voltage High/low
1-2-3-0      Power Supply Relay Secondary Circuit Voltage Low

Now my question about these codes is: How do i go about fixing/testing for these codes?
many thanks in advance for any help anyone can provide me.
Title: Re: omega bogging down + revving by itself
Post by: bigclive on 13 April 2011, 18:41:24
Update on the car:
the power problem seems to have gone since fitting the mass air flow sensor  :) lets hope it stays that way.
now the only other main problem is when the car is in park it auto revvs itself.

I have taken a short video of the rev counter to show what is happening. the car is in park with the foot off the accelerator.

https://picasaweb.google.com/lh/photo/pBWAQWNzKBp7yVM1xE7i_6gKj0ENWKc140CJQsv1gt
M?feat=directlink
Title: Re: omega bogging down + revving by itself
Post by: Jukeboxnut on 13 April 2011, 21:15:59
My old 1995 2.0 auto estate used to rev up and down on in Neutral and Park occasionally so I eventually took the IACV apart and found that there was fine grit on the brass plunger.  A thorough cleaning of the plunger and sleeve using alcohol cured the problem.
Title: Re: omega bogging down + revving by itself
Post by: freecall666 on 13 April 2011, 21:53:21
Quote
Update on the car:
the power problem seems to have gone since fitting the mass air flow sensor  :) lets hope it stays that way.
now the only other main problem is when the car is in park it auto revvs itself.

I have taken a short video of the rev counter to show what is happening. the car is in park with the foot off the accelerator.

https://picasaweb.google.com/lh/photo/pBWAQWNzKBp7yVM1xE7i_6gKj0ENWKc140CJQsv1gt
M?feat=directlink
the linc dont work... would look for a leak in fuel line, my just be a pin prick. also check the fuel pressure regulator.
Title: Re: omega bogging down + revving by itself
Post by: bigclive on 13 April 2011, 22:45:30

https://picasaweb.google.com/lh/photo/pBWAQWNzKBp7yVM1xE7i_w?feat=directlink

not sure whats happening when i paste the link into the reply box, it keeps seperating the link lol, if you copy the whole link into your browser it should work. copy the whole link right upto the word direct link and it should work.

Im pretty sure theres no fuel leak anywhere, I have checked the fuel regulaters and could not find any problems there either :¬(
and ive already had the iacv out and cleaned thougherly so this problem is really strange
Title: Re: omega bogging down + revving by itself
Post by: freecall666 on 14 April 2011, 10:26:10
that is a bit high for the revs. the olny other thing that not mechanical is the fuel being old. try getting your fuel from some were else. if you getting a lot of gray smoke that i would thing is the fault, try it and see how it gose.
Title: Re: omega bogging down + revving by itself
Post by: bigclive on 14 April 2011, 11:08:20
the fuel is not old, i put new fuel in the car the other day after changing the fuel filter and cleaning the iacv. we have 3 cars and a motorbike and use the same shell garage for all of them and none of the other cars or bike have any problems with the fuel from there. Im going to take the iacv off again today and give it another clean with carb cleaner to see if i missed anything. i used petrol to clean it the first time. so gonna try carb cleaner this time to see if that helps, maybe the petrol missed a bit lol.
(when the car did idle fine it was around 800-900rpm i believe)
but with the auto revving it dosnt settle down lol.

(no grey smoke by the way)
Title: Re: omega bogging down + revving by itself
Post by: Abiton on 14 April 2011, 11:25:11
Regarding the fault codes in reply 11, I'd be tempted to check the charging system; in other words what voltage do you get across the battery terminals with engine running?
Title: Re: omega bogging down + revving by itself
Post by: bigclive on 14 April 2011, 17:50:55
Quote
Regarding the fault codes in reply 11, I'd be tempted to check the charging system; in other words what voltage do you get across the battery terminals with engine running?


Hi, voltage going to the battery when running is coming up 13.55v to 13.77v (did the same test my a rover 620 that we also have and that comes up at 14.19v) not sure if all cars with same size engine put the same voltage to the battery or not? but if they do then there does seem to be a 1v differance.